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JOURNi^L OF 
AGRICULTURAL 
RESEARCH 


Volume III 


OCTOBER, 1914— MARCH, 1915 



PUBLISHED BY AUTHORITY OE THE SECRETARY 

OF agriculture, with the cooperation 

OF THE ASSOCIATION OF AMERICAN AGRICUL- 
TURAL COLLEGES AND EXPERIMENT STATIONS 


EDITORIAL COMMITTEE 


FOR THE ASSOCIATION 

N' RAYMOND PEARL 

Maine AgrieuHural }‘'xper{menl 

Sfation 

H. P. ARMvSBV 

I>ireclor, hist: I Hie of Animal Nutrition, The 
Pennsylvania fiiale College 

U. M. freeman 

Potanisl, Plant PaiholoQist, and Assistant 
Dean, Agricultural experiment Station of 
the University of Minnesota 


All correspondence rej^ardinsr articles from the Department of Agriculture 
should be addressed to Karl F. Kellerman, Journal of Agricultural Research, 
Washington, D. C. 

All correspondence regarding articles from Experiment Stations should be 
addressed to Raymond Pearl, Journal of Agricultural Research, Orono, Maine. 


FOR THE DEPARTMENT 
KARL F. KELLERilAN, Chaikm.i 

Physiologist and Assistant Chief, Bureau 
of Plant Industry 

EDWIN W. ALLEN 

Assistant Director, Office of experiment 
Stations 

CHARLES L. MARLATT 

Assistant Chief, Bureau of pntomology 


!l 



CONTENTS 


A Page. 

Relative Water Requirement of Plants. Lyman J. Briggs and 

H. L. Shantz I 

Heart- Rot of Oaks and Poplars Caused by Polyporus Dryophilus. 

Gkorgs G. Hedgcock and W. H. Long 65 

Decomposition of Soil Carbonates. W. H. MacIntire 79 

A Fungous Disease of Hemp. Vera K. Ch.arles and Anna 

Jenkins 81 

A More Accurate Method of Conipailng First -Generation Maize 

Hybrids with Their Parents. G. N. Collins ^5 

Natural Revegetation of Range Lands Based upon Gro^vth Re- 
quirements and Life History of the Vegetation. Arthur W. 

Sampson.... ‘ 

Pecan Rosette. W. A. Orton and Frederick V. Rand 149 

A Nitrogenous Soil Constituent: Tetracarbonimid. Edmund C. 

ShorEY and E. H. Walters 175 

Apple Boot Borer. Fred Brooks 179 

Changes in Composition of Peel and Pulp of Ripening Bananas. 

H. C. Gore 187 

Assimilation of Colloidal Iron by Rice. P. L. Gile and J. O. 

CarrERO 205 

Coloring Matter of Raw and Cooked Salted Meats. Ralph 

HoAGLAND 2H 

^il Content of Seeds as Affected by the Nutrition of the Plant. 

\V. W. Garner, H. A. Allard, and C. L. Fourert 227 

Studies in the Expansion of Milk and Cream. H, W. Search 251 

Life History of the ^lelon Fly. E. A. B.\ck and C. E. PemrErTon. 269 

I den ti location of the vSecds of Species of Agropyron. Rorkrt C. 

DahlbERG 275 

Observations on the Life History of Agrilus Bilineatus. Roy.al 

N. CuAPM.\N 283 

Effect of Dilution upon the Infcctivity of the Virus of the. Mosaic 

Disease of Tobacco. H. A. Allard 295 

Moldiness in Butter. Charles Thom and R. H. Shaw 301 

Susceptibility of Citrous Fruits to tlie Attack of tlie Mediterra- 
nean Fruit Fly. If, A. Back and C. E. Pemrerton 31 1 

Physiological Changes in Sweet Potatoes during Storage. Hein- 
rich H.asselrring and Lon A. H.\wkins 331 

Three-Cornered Alfalfa Hopper. V. L. Wildermuth 343 

Life History of the ]\Ieditcrranean iMuit My from the vStandpoint 
of Parasite Introduction. E. A. Back and C, E. Pemrerton. . 363 

III 



rv 


Journal of Agricultural Research 


voi. ni 


Page. 


Relation of Simultaneous Ovulation to the Production of Doublc- 

YolkedEggs. Maynie R. Curtis 375 

Brachysm, A Hereditary Deformity of Cotton and Other Plants. 

O. E. Cook 387 

Ability of Colon Bacilli to Survive Pasteurization. S. Henry 

Ayers and W. T. Johnson, Jr 401 

Fitting Logarithmic Curves by the Method of Moments. John 

Rice Miner 411 

Organic Phosphoric Acid of Rice. AticE R. Thompson 425 

Two Clover Aphids. Komi M. Patch 431 

Net Energy Values of Feeding Stuffs for Cattle. Henry Pren- 
tiss Armsby and J. August Fries. 435 

Air and Wind Dissemination of Ascosporcs of the Chestnut- 
Blight Fungus. P'. D. Heald, M. W. Gardner, and R. A. 

StudhalTer 493 

Index 527 

ERR.A.TA 

Page 32, Table XX, “ Trifolium should read “ Trifolium pratense.'^ 


Page 52, Tabic XXX, “ Linum should read “ Linum usitaiisiimumT’ 

Page 52, Table XXX, “ Cuctimhis sativa" should read *‘Cucuinis sativus.’* 

Page 53, Table XXX, “ Boutelona gracilis” should read ” Bouicloiia gracilis.” 

Page 53, Table XXXI, "Cucumis saliva” should read “ Cuciimis salivus.” 

Page 56, Table XXXIII, column head, “Ratio, i9i[3 to 1912,” should read “Ratio, 
1912 to J913. " 

Page 56, line 4 from bottom, “75 ±2 ’’should read “75±i,” 

Page 97, line 26, Salix nulallii” should read Salix nuttallii.” 

Page 106, Table II, ” Sutanion vr.lulinum ’’ should read ” Siianion veluiinum.” 
Page 165, Table III, insert line after “MgO” to read “ FcoOs- • 0.07 o.io o.cq o.:o.*' 

Page 165, Table IV, “FLO;/’ should read “FcnOj.” 

Page 165, Table IV, “Total 99-94 9S.36 ” 

should read “ Total 99-94 99-54 100.36 joo.oo.'* 

Page 166, Table V, “Total 10.1.45 ^04. 82 101.41 T01.99’* 

should read “Total 99. 73 100. 04 99-25 99.81.^’ 

Page 256, line 10, t,,,.- Q— Cf — (Cf); should read 

Page 256, line ii, should read “ 2 ’Cf a-}- JC,C2j3= 

IC,N.” 

Page 278, lines 37-3S, “(fig. 2)’’ should read “(fig. 3).” 

Page 279, line 19, “as” should read “at.” 

Page 279, legend for figure 2, “vSicle views of basal jiortions, etc.,” should read 
“Fig. 2. — Detail drawings of ventral view of seeds of Agropyron spp.: . 4 , AgroPyron 
repens; B, A. sniilhii; C, .- 1 . tencrum. X 9.” 

Page 280, legend for figure 3, “ Detail drawings of ventral view, etc.,” should read 
“ Fig. 3. — Side views of basal portions of seeds of Agropyron spp., showing the relative 
projection of the racliilla: A, Agropyron repens; B, .-I. smitkii; C, A. iencrum. X 9*” 
Page 280, legend for figure 4, “Edge of racliilla in Agropyron spp., etc.,” should 
read “Fig. a - — Edge of palea in Agropyron spp,, showing space and comparative size 
of bristles: A, Agropyron repens; D, A. smiihii; C, A. tcncrum. X 9.” 



ILLUSTRATIONS 

PI.ATES 

Riilative Water Requirement op Plants 

1 

Plate I- Pig* i* — General view of the plant inclosure used at Akron, Gilo., 
showing the pipe framework covered with a hail screen, with the board 
base surmounted by a single width of cheesecloth to protect the plants 
against high winds. Fig. 2.— General view inside the inclosure, showing 
the arrangement of pots and general conditions of grouth. G)m and 
sorghums are shovTi in the foreground, small grain in the background. 
Fig. 3.— General view of the inclosure photographed shortly after the grain 

in some of the pots had been harvested 

Plate II. Fig. i- — Pot planted with sugar beets, showing tlie wax seal around 
the plants and also the sealed holes where stand was not perfect. Fig, 3. — 
Weighing pots, sho>^'ing spring balance, weighing support, and general 
procedure. Two men operate the weighing support, one of whom lifts the 
pot by means of a windlass, while a third reads the balance and records the 
weight. By tliis mctliod weighings can be made at the rate of two per 
minute. Fig, ^.--Crindelia squarrosa (gum weed) and Artemisia jrigida 
(mountain sage), illustrating the growth of native plants used in the water- 

requirement measurements. 

Plate III. Fig. I. — Kubanka wheat, grown May 9 to September 3, 1912. Fig. 
2. — White Hull-lcss barley, grown May 16 to August 12, 1912. Fig. 3. — 
Kubanka wheat. vSet grown outside of shelter. May 9 to August 31, 1912. 
Fig. 4.“Kminer, groun Ma)' ii to August 12, 1912. Fig. 5. — Swedish Select 
oats, grown May 17 to August 23, 1912. Fig. 6. — ^Kharkov wheat, growm 

April 27 to August 28, 1912 

Plate IV. I'ig. i. — Northwestern Dent com, grown June 9 to September 16, 

1912. Fig. 2. — Hopi com, grown June 12 to September 26, 1912. Fig, 3. — 

White durra, gro^vn June 9 to September 26, 1912. Fig. 4. — Red Amber 
sorghum, grown June 29 to September 27, 1912. Fig. 5. — Minnesota Amber 
sorghum, grown June 9 to September 26, 1912. 

Plate V. Fig. i, — Sudan grass. First crop, grown May 28 to July 26, 1912. 
Fig. 2.- -Voronezh proso, grown June 5 to August 20, 1912. Fig. 3. — Kursk 
millet, grown June 9 to August 20, 1912, Fig. 4. — Select Grimm alfalfa, 
grown in the open, May 24 to July 27, 1912. Fig. 5. — Select Grimm alfalfa, 

grown in the shelter, May 24 to July 26, 1912 

Plate VI. Fig. r.— -Cowpea, grown June 17 to August 26, 1915. Fig. 2. — Hairy 
vetch, growm May 29 to July iS, 1913, Fig. 3,— Soybean, grown June i to 
August 26, 1913. Fig. 4, — Cantaloupe, grown Jime 14 to September 13, 

1913. Fig. 5. — Indian Flint corn, grown June 7 to Ar.gust 27, 1913. Fig. 

6. — McCormick potato, grow n June 5 to October 4, 1913 

Plate VJI. Fig. 1. — Triumj>h cotton in shelter, grown May 29 to September 
16, 1913. Fig. 2 . — ])oebcra papp^isa, grown July 25 to September 17, 1913. 
Fio. 3. — Rice in shelter, grown June 12 to September 16, 1913. Fig. 4. — 
General view^ of ti)c shelter, showing emmer at the left and White Hull-less 
barley at tlie right. Fig. 5. — General view in the shelter, showing com in 
the foreground 



VI 


Journal of Agricultural Research 


Vo], m 


Heart-Rot oi? Oaks and Poplars Caused by Polyporus 
Dryophilus 


Pftge- 


Plate VIII. Fig. x,~Quercus alba: Crescent- shaped "'soak," tlie initial stage 
of the piped rot produced by Polyporus dryophilus; from Arkansas. Fig. 

2 . — Quercus alba: A radial view of the rot in a limb, showing delignification; 
from Arkansas. Fig. 3. — Quercus ohlongifolia: A radial view of rot, showing 
delignification; from Arizona. Idg. 4. — Quercus alba: A final stage of the 
rot, radial vieiv, with more complete delignification; from Arkansas. 

Pig cj. — alba: A tangential view of tlic rot, showing delignification 
in pockets; from Arkansas. Fig. 6. — Quercus alba: An end view showing 
a cross section from the same tree as the preceding; from Arkansas. Fig. 

»— Quercus sp.; A section of oak from Von Tubeuf, sent to the junior 
writer as a specimen of the rot caused by Polyporus dryadeus in Europe. 

•Fig. 8. — Quercus sp.: The reverse side of the specimen shown in the pre- 
ceding. Fig. 9. — Quercus sp.: A section of oak from Europe, obtained by 
Von Schrenk, with a piped rot similar to that of Polyporus dryophilus. ... 78 

Plate IX. Fig. i. — A sporophore of Polyporus dryophilus, tuberous form on 
Quercus gamhelii; from Arizona. Fig. 2.— Sectional view of a sporophore 
of Polyporus dryophilus on Quercus gamhelii, showing the hard granular 
core, with whitish mycelial strands; also the pore layer; from New Mexico. 

Fig. — A sporophore of Polyporus dryophilwi on Quercus californica , show- 
ing tlie upper surface with a faint zonatioii; from California, lug. 4.— A 
section through a sporophore of Polyporus dryophihs on Quercus garryana, 
showing the structure of the hard granular core; from California. Fig. 5.— 

A front viewy showing the margin of the same .sporophore as in figure 3, 
representing the ungulate form. Fig. 6. — A view of the pore surface of 
an applanate sporophore of Polyporus dryophilus on Quercus alba; from 

Arkansas 7 ® 

Plate X. Fig. i. — A sporophore of Polyporus dryophilus, front view showing 
the margin, on Popvlus Iremuloides; from Colorado. Fig. 2.— A second 
sporophore from tlie same tree as figure i, showing an imbricated form, 
pify. — A view of the upper surface of a sporojihore of Polyporus rheades on 
PoPulus iremula; from Stockholm, vSweden. Fig. 4. — A sectional view of 
a sporophore of Polyporus corruscavs on Quercus; from IJpsala, Sweden. 

Fig. 5. — A side view' of an imbricate sporophore of Polyporus dryophilus, 
applanate form on Populus iremuloides; from Colorado. Fig. 6. A sec- 
tional view of the same sporophore as in the preceding figure, showing the 
hard granular core and whitish mycelial strands. Fig. 7. — A view of the 
upper surface of an applanate sporophore of Polyporus dryophilus on Quercus 
alba; from Arkansas. Fig. 8.— The T>ore surface of a sjxjrophore of Poly- 
porus dryophilus on Populus iTen\uloidc.i; from Colorado. 7 ^ 


A Fungous Disease of Hemp 

Plate XI. A hemp plant, showing upper branches attacked by the fungous 

Botryosphaeria marconii ^ 

Natural Revegetation of Range Eands Based upon Growth 
Requirements and Life History op the Vegetation 

Plate XII. Fig. r.— View of the lower grazing lands in the Wallowa National 
Forest. Fig. 2.— Characteristic open stand of western yellow pine and 
dense cover of herbaceou.s vegetation, mainly pine-grass {Calamagrostis 
pubescens), Wallowa National Forest. Transition zone (yellow-pine asso- 
ciation). Fig. 3.— A bunied-over area of lodgcpolc pine, with character- 
istic dense sapling stand 



Oct., i9r4-Maf., 1915 • 


Illustrations 


VII 


Page. 

Plate XIII. Fig. i. — Dense stand of lodgepole pine, with undergrowth of red 
huckleberry {Vaccinium scoparium). Canadian zone (lodgepole^pine 
association). Fig. 2 . — A flat eminence in the Hudsonian zone , showing the 
characteristic clumped growth of whitebark pine and Alpine 1^. Fig. 

2. — Irregular topography of the upper grazing lands. Hudsonian zone 

(whitebark-pine association) 148 

Plate XIV. Fig. i. — Arctic- Alpine and upper-subalpine region, where forage 
• is sparse, due to poor soil, short growing season, and unfavorable climate. 

Fig. 2. — Mountain range lands prior to the beginning of growth and germi- 
nation. Fig. 3. — Same view as shown in figure 2, but more in detail, 

showing the condition eight days later (June 30) 148 

Plate XV. Fig. 1. — Contrast in the progress of the flower stalk production 
of mountain bunch -grass on portion of range which has been completely ^ 
closed to grazing for a period of three successive years and on range which 
has been subject to continued early grazing. Fig, 2. — Western porcupine 
grass (Siipa occidentalis), showing empty glumes and floret witli the scale 
and its awned projection to the left; to tJie right the floret witli glumes 


removed, showing the sharp-pointed, slightly curved seed tip. Fig. 3. — 
Average development of the root system and aerial jxjrtion of mountain 

bunch-grass at end of the first growing season : 148 

Pi.aTE XVI. Mountain bunch-grass, showing root development and aerial 

growth at the end of the second season 148 

Plate XVII. Mountain bunch-grass in the spring of the third year of growth 
'just before producing flower stalks, showing the natural position and length 

of the elaborate root development and aerial growi:h 148 

Plate XVIII. Mountain bunch-grass at the end of the third year, showing 

tliree flower stalks and inflorescence 148 

Plate XIX. Sickle sedge {Carex uvihellaia hre-cirosiris), showing offshoots from 

the rootstocks and flower stalks with fruit in the process of development . 148 

Plate XX. Fig. i. Station 4 on Stanley Range as it appeared on July 12, 1907. 

Fig. 2. — View of station 4 on Jul)' 13, igoQ, after two years’ protection from 
grazing animals. Fig. 3. — Vicw'of quadrat i, established on July 10, 1907. 148 

Plate XXI. Fig. I.— Quadrat 1, as it appeared on July 16, 1909. Fig. 2. — 

Area of mountain Ijunch-gniss closed to grazing animals on July S, 1907. 

Fig. 3. — View of open range contiguous to area shown in figure 2 148 

Plate XXI L \ae\vof plot in tlie Transition (ycllnw-pinc) zone which ha.sbeen 
protected from grazing animals for three successive years, showing contrast 

in carrying capacity with contiguous open range 148 

Plate XXIII. Fig. i. — View of portion of allotment at medium elevation 
where the destruction of forage seedlings due to grazing and trampling 
was studied. Fig. 2. - Dense stand of smooth wild lye {Elytnus ghucus) 
and short-awned bronie-grass {Bronms viargmaUis) seedlings. 148 

Peca.v Rosette 

Plate XXIV. Fig. I. — One normal pecan leaf cuid two leaves >vith rosette 

from Dewitt, Ga. Fig. 2. — Pecan shoot with early symptoms of rosette. . . . 174 

Plate XXV. Rosetted pecan leaf showing perforations due to the failure of 

part of the mesophyll to develop 174 

Plate XXVI- Fig. 1. — Pecan shoot in advanced stages of rosette. Fig. 3. — 

Normal pecan shoot for comparison wnth rosetted shoot. 174 

Plate XXVII. Fig. i. — 'Young orchard pecan tree with a moderate attack of 
rosette on the left side and seriously dying back from the disease on the 
Ollier side. Fig. 2. — Young orchard pecan tree in advanced stages of 
rosette 174 



VIII 


Journal of Agricultural Research 


Vol. Ill 


Page. 

Pi,ATK XXVIll. Fig. I. — Young orchard tree with severe attack of rosette. 

Fig. 2 . — Rosetted pecan tree cutoff to the stump the preceding season, with 
tlic present season’s growth again distinctly showing rosette. Fig. 3. — 

Tw'o seedling pecan trees planted the same day from the same lot of seed- . 
lings 174 

ApptF: Root BoKi^R 

Plats XXIX. Figs. i and 3. — Sections of an apple root, showing burrows of 
the apple root borer [Agrilus liitaticollis). Fig, 2. — Cross section of the 
trunk of a young apple tree, showing burrows made by the larvae of the 

apple root borer in ascending the trunk to pupate 186 

Plats XXX, Fig. i. — Agrilus vittaiicoUis: Barva(f), pupa (6), and adult (a) of 
tlic apple root borer In the pupal cell. Fig. 2.—Xylopkruridea agrili, a 
common parasite of the apple root borcr. Fig. 3. — Section of trunk of 
young service tree, showing bclo^v the white egg and above the e.\it hole 
of tlie apple root borer. Fig. 4. — Xylophruridea egrili: harvae of the para- 
site; one feeding on the larva and the other in the pupal cell of its host. . . 186 

Platp) XXXT. Fig. I. — Agrilus vitiaticnllis: Fgg on trunk of young service 
tree. Fig. 2, — Agrilus vitiaticollis: Feeding form of larva. Fig. 3.-- 
Agrilus vitiaticollis: Contracted form of laiu^a as taken from pupal cell. 

Fig. 4. — Agrihts vitiaticollis: Pupa. Fig. 5. — Agrilus vittaiicollis: a, Adult, 
or beetle; b, claw; c, antenna. Fig. 6. — Xylophruridea agrili, a parasite 
of the apple nx)t borer: Ihipa 186 

Coloring Matter op Raw and Cooked Salted Meats 
Plate XXXII. Fig. i.— Oxyhemoglobin, ox blood. Fig. 2. — Oxyhemoglobin, 


ox blood. Fig. 3, — NO-hemoglobiii, ox blood. Fig. 4. — Mcthemoglobin, 

ox blood. Fig. 5, — Methcmoglobin , ox blood 226 

Plate XXXIII. Fig. i. — Oxyhemoglobin, sheep blood. Fig. 2. -Oxyhemo- 
globin, sheep blood. Fig. 3. — NO-hcmoglobin, sheep blood. Fig. 4. — 
NO-hcmoglobin, pig blood. Fig. 5. —N 0 -hemoglobin, pig blood 226 


IlJENTlPMCATlON OP THE SEEDS OF SpEClES OK AgrOPYRON 
Plate XXXIV. Agropyron repens: Spikes showing degrees of variation which 


may occur. A , Typical spike 282 

Plate XXXV. Agropyron smiihii: Spikes showing degrees of variation. A, 

Typical spike 282 

Plate XXXYI. Agropyron ienerum: Spikes showing degrees of variation. A, 

Typical spike 282 

Plate XXXVII. AyrD/»}Touspp.: Typical seeds and spikelets. Fig. i.— 

pyron repens, F'ig. 2. — Agropyron swiihii. Fig. 3. — Agropyron ienerum. . 282 


Observations on the Life History of Agrills BilinEatus 

Plate XXXVIII. Fig. 1. — Agrilus bilineaius: Eggs in position in the bark of 
an oak tree. Fig. 2. — Agrilus bilineatus: Cluster of newly laid eggs. Fig, 
3. — Agrilus bilineatus: Eggs shortly before hatching. Fig. 4. — Agrilus 
bilineaius: Newly hatched larva. Fig. 5. — Agrilus bilineatus: Mature larva. 
Fig. 6. — Agrilus bilineaius: Larva in its cell. Section made perpendicu- 
lar to the surface of the bark. A, Point at which adult will emerge; /?, 
burrow stopped with frass. Fig. 7. — A grilus bilineaius: Pupa in cell. Sec- 
tion made parallel to the surface of tlie bark. h'ig. 8. — Agrilus bilineaius: 
Adult fL-mah'. f'ig. 9. — Agrilus bilineaius: Adult male 


294 



Oct., X9i4-Mar., 1915 


Illustrations 


IX 


Page. 

Plate XXXIX. Fig. i. — I^eaf showing work of four Agrilus beetles in 24 hours. 

Fig. 2. — Hole in bark made by adult Agrilus in emerging from pupal cell. 

Fig. 3. — Larvse of Agriltis bilineatus and their burrows. Fig. 4. — Complete 
burrow of a larva of Agrilus bilineatus. A, Point at which larva hatched; 

. B, beginning of second instar; C, beginning of third instar; D, beginning 
of fourth instar; E, pupal cell 294 


Susceptibility op Citrous Fruits to the Attack op the Mediter- 
' RANEAN Fruit Fly 


Plate Xh. Fig. i. — Orange infested with larvie of the Mediterranean fruit fly 
{Ceratiiis capitaia). Fig. 2 . — Orange infested with larvae of the Mediter- 
ranean fruit fly {Ceratitis capitaia) , showing two breathing holes of the larvae 

in the decayed area 

Plate XFI. Cross section of shaddock No. i, showing the thick, loose texture 
of the rag w'ith darkened area above and to the right showing the channels 

made by well-groum Mediterranean fruit-fly larvse 

Plate XFII. Fig. i. — Cross section of the orange shown on Plate Xh, figure 2. 

Fig. 2. — Orange containing 8; punctures in the rind 

Three-Cornered Alfalfa Hopper 


Pi.,atE XLIII. Fig. I. — The thrcc-comered alfalfa hopper 

Adult, fl, View from side; h, view from front. Fig. 2. — The three-cornered 
ahalfa hopper: a, Nymph in first stage; b, egg. Fig. 3.— The three-cor- 
nered alfalfa hopper: Nymph in second stage. Fig. 4. — The three-cornered 
alfalfa hopper; Nymph in third stage. Fig, 5. — The three-cornered ahalfa 
hopper: Nymph in fourth stage. Fig. 6. — The three-cornered alfalfa hop- 
per: Nymph in fifth stage. Fig. 7. — An alfalfa stem showing feeding pimc- 
tures of the thrce-comercd alfalfa hopper: a, Ring or girdle of punctures 
around the stem; h, gall resulting from girdling ^62 


Fife History of the Mediterranean Fruit Fly from the Stand- 
point OF Parasite Introduction 


Plate XFIV. Fig. r. — Wooden boxes, 14 by 12 by 3 inches in size, used in 
obtaining pupae of fruit flies. Fig. 2. — Contrivance used for keeping the 
infested fruit free from the sand and bringing the emerging larvae to a 

central container where they may be gathered quickly 

Plate XLV. Fig. I.— Method of keeping adult fniit flies alive over long periods. 
Fig. 2.— An apple after having been suspended for one day in a jar con- 
taining Mediterranean fruit flics 


Relation of Simult.\neous Ovulation to the Production of 
Double-Yolked Eggs 

Plate XEVI. — Fig. i. — Large yolk (weight, 30.12 gm.) with two germ disks; 
found in a large hen's egg. Fig. 2. — Fused immature yolks (weight, 1.45 
gm.); found in a small hen's egg. Fig. 3. — T>'pe I double-yolked egg, 
showing two yolks with separate vitelline membranes but inclosed in a 

common clialaziferous layer ’ 386 

Plate XLVII. Fig. i. — Type I double-yolked egg, showing two yolks with sep- 
arate vitelline membranes but inclosed in a common chalazifcnous layer. 

Fig. 2. — Type 11 double-yolked egg, showing two yolks with separate cha- 
lazal membranes but common thick albumen. 


386 



X 


Journal of Agricultural Research 


Vol. HI 


Page. 

PUATE XLVIIL Fig. I.— Type II double-yolkcd egg, showing two yolks with 
some separate and some common thick albtimcn envelopes. Fig. 2. — 

Type III doiible-yolked egg, showing two yolks with all the thick albumen 

separate 3^ 

Plats XLIX. Fig. i.— ^hell of type III double-yolkcd egg, which shows 
external evidence of its double nature by a seam in the shell. Fig. 2. — 

The inside of the shell shown in figure i, showing the fold of egg membrane 

which projected between the two component eggs 386 

Plate L. Oviduct removed from a laying bird and cut open along the point 
of attachment of the ventral ligament. A, Funnel; B, albumen-secreting 

region; X, isthmus ring; C, isthmus; D, shell gland; and E, vagina 386 

Plate LI. Fig. i. — Ovary of a pullet, showing the follicles which produced 
the yolks for the double- 3 'olked egg shown in Plate XLVIII, figure i. 

"Fig. 2. — Ovary of a pullet, showing follicles which produced the yolks for 
a double-yolked egg similar in structure to the one showm in Plate XLVIIT , 

figure 2 3 ^^ 

Plate LII. Fig. I. — Ovary of a pullet, showing a series of rcsorbing follicles, 
two of which (probably C and C) produced the yolks for the double-yolkcd 
egg shown in Plate XLVI, figure 3, Fig. 2. — Ovary of a bird, showing 
the two largest rcsorbing follicles, one of which produced the yolk with 
two germ disks shown in Plate XLVI, figure i 386 

Brachysm, a Hereditary Deformity oE Cottox and Other 
Plants 


Plate LHI. Abnormal simple leaf on fruiting branch of Eg^’ptian cotton, 
accompanied by abnormal leaf-like bract, remainder of involucre and 

floral bud removed 4°® 

Plate LIV, Normal 3-k)bed leaf of fruiting branch of Eg>'ptian cotton, accom- 
panied by normal involucral bract for comjiarisun with Plate LIU 400 

Plate LV. Abnormal leaf of fruiting branch of Eg)’ptian cotton witli one 

stipule enlarged and the lobe of the same side wanting 400 


Plate LVI. Brachytic fruiting branches of “cluster” cotton (Willcts Red 
Leaf) shortened to a single intemodc by abortion of terminal bud. Fig. i. — 
The boll at the right is borne by .a short branch from an axillary bud. 
Fig. 2. — Tlie boll at the right is borne by the shortened fruiting branch. 
The left-hand boll represents a shortened branch in the axil of the leaf that 


subtends the fniiting branch 400 

Plate LVI I. Nonnal and brachytic joints on same fruiting branch of Upland 

cotton 400 

Plate LVIII. Branches of abnormal variation of Upland cotton, with abortive 
buds remaining attached to branches by dccurrcnt jjcdicels and elongated 
bud scars. The left-hand branch shows abnormal inequality in the lengths 

of the in te modes 4 oo 

Plate LIX. Portion of brachytic fmiting branch of Simpkins cotton producing 

twin fasciated branches from an axillaiy^ bud 400 

Plate LX. Portion of fniiling branch of Columbia cotton, with one intenuHk* 

adnate to the pedicel of the boll of the preceding inteniodc 400 


Pi.ate LXI. Fig. I.-- Plant of Dale Egyptian cotton, showing complete abor- 
tion of fruiting branches on the main stalk, while llie vegetative branches 
of the same plant produced a few fruiting branches and ripened a few Iwlls. 

Fig. 2. — End of main stalk of plant shown in figure i, showing aliortion of 
terminal bud and compensatory^ thickening of the jjetiolcs 400 



Oct., 1914-Mar., 1915 


Illustrations 


XI 


Pirate Ktids of main stalks of two plants of Dale Egyptian cx)ttoti, show- 

ing simple fruiting branches and closely similar axillary fruiting branches. 400 

Air and Wind Dissemination of Ascospores of the Chestnut- 
B EIGHT Fungus 

Peate EXIII. Fig. r. — Petri -dish culture 5044 from 12 minutes' exposure of 
chestnut-bark agar, made on September 20, 1913, 2 hours and 8 min- 
utes after the cessation of a rain, at station 51, located 27 feet from 
the nearest lesion. Fig. 2. -Petri-dish culture 5041 from 16 minutes’ 
exposure of chestnut-bark agar, made on September 20, 1913, i hour and 55 
minutes after the cessation of a rain, at station 49, located 414 feet from 
the source of the spores 526 

Peate LXIV. Fig. I,— Ascospore trap 51. This consists of a wooden bracket • 
which supports an object slide over perithecial pustules. Fig. 2. — 
Ascospore trap 52. Fig. 3. —Water spore trap located at Station V 526 

Peate LXV. Fig. I.— View looking toward the coppice growth from water ^ 
spore-trap Station V. Fig. 2.— View of a mixed chestnut and oak grove 
taken from w ater spore -trap Station VI 526 

TEXT FIGURES 

Relative Water Requirement op Plants 

Fig. I. Evaporation from a free-wnter surface (tank) at Akron, Colo., in 1911 

and 1912 8 

A Fungous Disease of Hemp 

Fig. I. Microscopic characters of the hemp fungus Boiryosphaeria marconii. 

A, Sketch of a section of stroma from culture, showing developing 
perithecia: a, microconidial stage, h, ascosporic stage. B, An ascus 
with ascospores. C, Ascospores. D, Macroconidia. Conidiophores 
of the Dendrophoma stage. F, Microconidia 82 

Naturae Re vegetation of Range Eands B.\sed upon Growth 
Requirements and Life History of the Vegetation 

Fig. r. Curve show ing the variation in the mean temperature in the Transition, 

Canadian, and Hudsonian grazing zones in 1909 gg 

2. Diagram showing the total precipitation in the Transition, Canadian, 

and Hudsonian grazing zones during July, August, and September, 

1909, inclusive gg 

3. Curve showing the comparative daily evaporation in the Transition, 

Canadian, and Hudsonian zones in 1909 roo 

4. Curve showing the maximum and minimum temperature records in the 

Hudsonian zone (wLitebark-pine association ) no 

5. Chart of permanent and denuded quadrats i and 2 in station 4, es- 

tablished on July 3, 1907 122 

6. Chart of permanent and denuded quadrats i and 2 in station 4, remapped 

on July 12, 1909 '. 123 

Pecan Rosette 

Fig. 1, Map showing the known distribution of pecan rosette in the United 

States 1^0 



XII Journal oj Agricultural Research voi. ki 

Changes in Composition op Peel and Pulp of Ripening Bananas 

Page, 

Fig. I. Constant-temperature humidor 193 


Coloring Matter op Raw and Cooked Salted Meats 

Fig. I. Spectra of hemoglobin and some of its derivatives: i4 , Absorption spec- 
trum of a solution of oxyhemoglobin; B, absorption spectrum of a 
solution of N 0 -hemoglobin; C, absorption spectrum of a solution of 
hemoglobin prepared by treating a solution of oxyhemoglobin with 
hydrazin hydrate; D, absorption spectrum of a solution of met- 
hcraoglobin prepared by treating a solution of oxyhemoglobin with 
potassium ferricyanid ; E, absorption spectnim of an alkaline solution 
of hematin; F, absorption spectrum of a solution of hcmocliromogen 
prepared by treating an alkaline solution of hematin witli hydrazin 
hydrate; G, absorption spectnim of a solution of NO-hemochro- 
mogen 215 

Studies in the Expansion op Milk and Cream 
Fig. t. Specific gravity of milk and cream at 35^/4° C., showing value of a 


and ^ 261 

Specific gravity of milk and cream at 35°/4° C., showing relation bc- 

tw'een density and percentage of butter fat 261 


Identification op the Seeds of Species op Agropykon 


Fig. I, Detail drawings of dorsal view" of Agropyron spp.: A, Agwpyron repens; 

B, A, smithii; C,A.ienenim 27S 

2. Detail drawing of ventral view of seeds of Agropyron spp. : A, Agropyron 

repens; B, A. smithii; C, A. tenenun. (Sec “Errata.’’) 279 

3. Side views of basal portions of seeds of Agropyron spp,, showing the 

relative projection of the rachilla: A , Agropyron repens; B, A , smithii; 

C, A, iencnim. (See “ Errata.’’) 280 

4. Edge of rachilla in Agropyron spp. , showing shape and comparative size 

of bristles: A, Agropyron repens; B. A. smithii; C, A. icncrum 280 

Moldiness in Butter 

Fig. I. Graph showing the effect of salt on molding 308 


Susceptibility of Citrous Fruits to the Attack op the Mediter- 
ranean Fruit Fly 


Fig. 1. Cross section of peach, showing egg cavity of the Mediterranean fruit 

fly with eggs 320 

2. Cross section of peach, showing the general shriveling of the walls of the 

egg cavity and the separation of the eggs 320 

3. Section of grapefruit rind, showing two egg cavities, one in cross section. 321 

Three-Cornered Alpalfa Hopper 

Fig. 2. Map showing distribution of the three-cornered alfalfa hopper (S/teto- 

cephalafestina) in the United States. 344 

Ability of Colon Bacilli to Survive Pasteurization 


Fig. 1 . Curve showing results of heating cultures of colon bacilli for 30 minutes 
at various temperatures 


404 



Oct.. 1914-Mar,, 1915 Illusiraiions xiii 


Two Cmdver Aphids 

Page. 

Fig, 1. Aphis hrevis: Antenna of fall alate female collected from hawthorn .... 432 

2, Aphis brevis: Antenna of alate male 43^ 

3. Aphis bakeri: Antenna of alate female collected from clover 433 

Net Ensrcy Valdes op Feedi.ng Stupps por Cattle 

Fig, I. Graph showing the dry matter eaten and the increments of heat produc- 
tion due to standing, computed per 500 kg. live weight per 24 hours. 455 
2. Graph showing the relation of heat production to dry matter consumed, 

computed per 500 kg. live weight 472 

Air and Wind Dissemination op Ascospores op the Chestnut- 
Blight Fungus 

Fig. I. Map of chestnut coppice growth at West Chester, Pa. , in and near which 
the experiments on wind dissemination of the chestnut-blight fungus 
were carried out 4gy 

2. Map showing the location of some of the important outlying exposure- 

plate stations 498 

3. Map lowing the location of w’ater spore- trap stations Nos. I to VI. . , . 520 




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SuiiscKUTiON Pki: Year, 12 Numbers, 

A 




JOlfflAL OF AGRIOITDRAL RESEARCH 

DEPARTMENT OF AGRICULTURE 

VoL. Ill Washington, D. C., October 15, 1914 No. i 


rkivATive water requirement of plants 

By I/YMAN J. Briggs, Biophysicist in Charge, Biophysical Investigations, and H. E. 

Shanxz, Plant Physiologist, Alkali and Drought Resistant Plant Investigations ^ 

Bureau, 0/ Plant Industry 

INTRODUCTION 

The marked differences in the quantity of water required by different 
species of plants for the production of a given weight of dry matter when 
grown under the same environmental conditions is a matter of scientific 
interest and of great economic importance in regions of limited water sup- 
ply. The measurements which have heretofore been made have for the 
most part been limited to a few species and have been carried out under 
such varied environmental conditions that comparison is difficult. The 
writers have therefore undertaken the measurement of the water require- 
ment of representative species and varieties of the principal crop plants, 
grown at the same place and under as nearly uniform conditions as to time 
as the temperature requirement and life history of the different crops will 
permit. The first series of measurements were made at Akron, Colo., in 
1911 (Briggs and Shantz, I9i3a)h These measurements were ex- 
tended in 1912 and 1913 to include many species w'hose w*ater requirement 
had never before been detennined. The later measurements form the 
subject of the present paper. The writers desire to express their obliga- 
tion to Messrs. R. D. Rands, A. SIcG. Peter, H. Martin, F. A. Cajori, N. 
Peter, and G. Crawford for efficient and painstaking assistance in con- 
nection wdth these experiments. 

EXPERIMENTAE CONDITIONS 

The experimental procedure in 1912 and 1913 was similar to that in 
the earlier experiments. The plants were grown to maturity in large 
galvanized-iron pots holding about 115 kg. of soil. Each pot was pro- 
vided with a tight-fitting cover having openings for the stems of the 
plants, the annular space between the stem of the plant and the cover be- 
ing sealed with wax. The loss of water ^Yas thus confined almost entirely 
to that taking place through the leaves, and the entrance of rainfall was 
almost wholly excluded. The wax which has been found to be the most 

1 llibliographic citations in parentheses refer to ‘'Literature cited," p. 63-63. 


(I) 


Journal of Agricultural Research, 

Dept, of Agriculture. Washington, U, C. 


Vol. HI. No. I 
Oct. IS, 1914 
G-33 



2 


Journal of Agricultural Research 


Vol. in, No. I 


satisfactory for sealing the openings about the stems consists of a mixture 
of four parts of unrefined beeswax with one part of tallow. 

Six pots of plants of each variety * were used, and the water require- 
ment of each pot was determined independently, in order to provide a 
basis for the calculation of the probable error of the mean. In making 
this calculation, Peter’s abridged method, based upon the sum of the 
departures, has been employed.^ 

The term “water requirement,” when employed in the following pages 
without further restriction, indicates the ratio of the weight of water 
absorbed by a plant during its growth to the weight of the dry matter 
produced, exclusive of the roots (Briggs and Shantz, 1913a, p. 7), 
The plants were dried to constant weight in a steam-heated oven, main- 
tained at approximately iio'^ C. When the plants produced grain, the 
water requirement based upon the weight of the dry grain is also given. 
The percentage of grain produced by the plants grown in the pots usually 
compared favorably with the field performance. Unless a normal per- 
centage of grain is produced, the water-requirement ratio based on grain 
production should not be applied to crops grown under field conditions. 
In a few instances the water requirement based upon the weight of roots 
or tubers has also been determined. 

SCREENED INCEOSURE 

To protect the plants from birds and severe hail and wind storms, it 
was found necessary to conduct the experiments in a screened inclo- 
sure. The inclosure used in 1911 consisted of a wooden framework 
covered with wire netting of ^^-inch mesh. This framework shaded the 
plants somewhat, being made sufficiently rigid to support a track above 
each row of cans, from which the cans were suspended during weighing. 
To reduce the shading effect, a new inclosiire was provided in 1912, the 
framework of which was made of i-inch galvanized-iron pipe with pipe 
posts 9 feet high at intervals of 8 feet. The framework to a height of 3 
feet was covered with a wooden wall which came slightly above the top 
of the pots. The remainder was covered with No. 21 galvanized- wire 
netting of )^-inch mesh. General views of the inclosurc are shown in 
Plate I. 

Although the new inclosure reduced the shading effect, pyrheliometric 
and total radiation measurements made inside and outside the inclosure 
still showed a measureable reduction in the radiation due to the shade 
of the screen. Measurements made with an Abbot silver-disk pyrheli- 
onieter (Abbot, 1911) showed that the intensity of the direct radiation 

> The recorded strains used in these measurements were obtained from the following officess of the Bureau 
of Plant Industry: Foreign Seed and Plant Introduction (S. P. 1); Cereal Investigations (C. I.); Alkali 
and Drought Resistant Plant Investigations (A. D. I.). 

® The formula used was Rm=< 5 . 84 S “ where Rm=the probable error of the mean, ltl**the sum of 

n\n-i 

the departures, and «"=numberol detcrininations. 

A probable error based upon six determinations docs not necessarily represent strictly the actual fre- 
quency diagram, and this must be borne in mind in the consideration of probable errors. For a discussion 

* ' - > cno <' Cf ” I TnCkSV 



Oct. IS. I«i4 


Water Requirement of Plants 


3 


from the sun was reduced about 20 per cent by the inclosure at midday 
in midsummer, while total radiation measurements made with a differ- 
ential telethermograph (Briggs, 1913) gave approximately the same 
reduction. Simultaneous measurements of the water requirement of 
wheat, alfalfa, and cocklebur grown inside and outside the inclosure in 
1913 showed that the inclosure reduced the water requirement about 22 
per cent. The water-requirement measurements must therefore be con- 
sidered relative rather than absolute. In this connection it should be 
recalled that plants growing under field conditions are also mutually 
shaded and otherwise protected to some extent. The writers’ measure- 
ments in 1913 show that wheat grown in pots sunk in trenches and sur- 
rounded by a field of grain has a water requirement 10 per cent above 
wheat grown in the inclosure and 10 per cent below wheat grown outside 
the inclosure in a freely exposed wind-swept position. (See Table I.) 
The stand of wheat about the trench was below normal, owing to the dis- 
turbance of the plants in trenching and in caring for the pots. The potted 
plants in the trenches \vere consequently more exposed than if growing 
normally in a field of grain. The water requirement of the potted plants 
in the trench is therefore somewhat above that of plants normally pro- 
tected. From this comparison it appears that the inclosure measure- 
ments, at least in the case of wheat, are less than 10 per cent below the 
water requirement of plants exposed under field conditions. 


TadlE 1 . —Effect of the screened inclosure on the water requirement of wheat at Akron, 
CoU}., in rpjj ’ 


Plant and period of growth. 

Pot 

No. 

Dry 

Grain. 

Water. 

Grain, 

Water requirement 
based on — 






Grain. 

Dry matter. 

1913- 

Kubanka, C. I. 1440 
( Triticum durum ) , 
check series, May 
22 to Aug. 13. 

i 

7 

8 

9 

10 

11 

12 

Grams. 
162. 2 
167. 4 
143* 4 
151. 6 
148. g 
159- 3 

Grams. 

5 

63*9 

49.0 
5 r- 4 
56. 5 
50- 3 

K Has. 
103. 8 
105. I 
gi. 2 
93 - I 
^ 9 - 5 
102. 2 

Per cenl. 

35 

38 

35 

34 

38 

32 

1.837 

645 

I, 861 

1, 810 

h 584 

2, 032 

640 

628 

636 

614 

601 

642 

Mean 

i 





_L 









o 27±5 

Kubanka, in field, 
May 22 to Aug. 13. 

1 

2 

^ 3 

4 

s 

6 

142. 5 
151. I 
153- 4 
r <t6. 0 ' 
143 - 9 
167. 8 

46. 6 

43 - 9 
48. 9 
42. 8 
48. 2 
44. 9 

8r. 4 
80.8 
82. 9 
88. 4 
83-3 

97 - 3 

33 

29 

32 : 

27 , 

33 
27 ' 

h 745 
r, 840 

1,694 

2,063 

T, 726 

2, 167 

571 

534 

540 

566 

579 

580 

Mean 















502±0 

Kubanka, in shelter, 
May 23 to Aug. 13. 

73 

74 

75 

76 

77 

78 

294.8 
273 - 4 

257. 0 
304. 2 
253- 3 
299. 6 

106. 5 
101. 4 
97. I 
ri6. 2 
93 - S 
n6. 8 

135 - 9 
122. 4 
156. 0 
121.3 

1 50. 2 

36 

37 

38 
32 

37 

39 

1,410 

1,340 

I, 261 

b 342 

293 

I, 286 

510 

497 

476 

513 

479 

502 

Mean 






I, 322±i6 

496 ±S 



4 


Jouryial of Agricultural Research 


Vol. Ill, No. r 


WI$IGHING AND WATI^RING 

The discarding of the overhead track necessitated the construction 
of a movable support for weighing the cans. The weighing support 
used is shown in Plate II, figure 2. It was constructed of i-inch gal- 
vanized-iron pipe and consisted of a crossbar which spanned the row and 
which was supported at each end by two bent posts. These posts were 
fitted with floor plates secured to two wooden skids, which slid along 
the ground on either side of the row of cans. In the earlier weighings 
the pots were suspended from a rope running through pulleys to a small 
windlass located on one of the posts of the support (PI. 11 , fig. 2). The 
windlass was later located directly beneath the crossbar and was operated 
through a chain-and-sprocket drive. 

Each pot was provided with bale ears by which it could be suspended 
directly from the balance by chains. When the plants were not suffi- 
ciently high to come in contact with the weighing apparatus, pots could 
be weighed at the rate of two a minute if two men handled the support and 
a third recorded the weight. When 300 pots or more are to be weighed 
three times a week, as was the case at Akron, rapidity in weighing be- 
comes important. 

The initial and final weighings have been made with an accuracy of 
one-fifth of a kilogram, either with a platform balance or a sensitive 
spring balance calibrated and corrected for temperature. Intermediate 
weighings have been made throughout with a spring balance calibrated 
by means of a sealed check pot weighing 1 30 kg. 

The water in all cases has been added from calibrated 2-liter flasks 
(Briggs and Shantz, 1913a, p. 11). The neck of each flask is cut so 
as to deliver 2 liters of water when brimful. The flasks are filled by 
submersion. In some of the later work a tank with a framework arranged 
for keeping a number of flasks submerged has been used. No time is 
thus lost in filling flasks or in adjusting the contents to a fiducial mark. 

SOIL FERTILIZER 

Surface soil from the experiment farm was used for filling the pots. 
Since it is well known that the water requirement is increased by a 
deficiency in the plant food supply (Briggs and Shantz, 1913b, pp. 31-56), 
the same quantity of a complete soluble fertilizer was added to each pot 
at each station at intervals during the growth of the crop. The fertilizer 
in 1912 was applied at the rate of 50 p. p, m. of PO4, 100 p. p. m. of NO3, 
and 65 p. p. m. of K, all based on an assumed dry soil mass of 100 kg. 
per pot.^ The phosphoric acid was applied as sodium phosphate; the 
nitrogen and potash as potassium nitrate. This amount of fertilizer was 
divided into four equal portions and applied at intervals during the 
active growth of the crops, the first application being made soon after 

* Approxiaiatdy on«.--half yf this guantity was used iu 1913 and was applied as in 191J. 



Oct. 15, 1914 


Water Requirement of Plants 


5 


the plants had become well established. In practice it was found con- 
venient to make up ^ large quantity of the fertilizer solution of such 
concentration that 2 liters contained one-fourth of the total quantity 
required for one pot. The addition of this quantity to each pot was 
followed immediately by 2 liters of water. 

To test the influence of the fertilizer, one standard set of six pots of 
Kubanka wheat was grown without fertilizer at Akron, for comparison 
with the fertilized sets. The detailed results are given in Table 11. The 
water requirement of the unfertilized set was 4 i 2 per cent below that of 
the fertilized set when based on the production of dry matter, and i ±4 
per cent above, when based on grain production. The results therefore 
indicate that the additional plant food was not needed at this station, 
the water requirement of the two sets agreeing (within the errors of the 
experiment) whether based on the production of dry matter or on the 
production of grain. In 1911 the water requirement of the unfertilized 
set ^ at Akron was 6±3 per cent above the fertilized set when compared 
on the basis of dry matter, although the ratios based on grain production 
were the same. 


Table of fertilizer on the water requirement of wheat at Akron, Colo., in IQT 3 


, 






Water requirement 








Plant and period of growth. 

Pot 

Xo. 

Dry 

Grain. 

Water. 

Grain. 







Grain. 

Dry matter. 



1912. 


Grams. 

Grams. 

Ki/os. 

Per cent- 




I 

270. 0 

108. 2 

9.r I 

40 

879 

352 

Kubankd, C. I. 1440 

2 

252- 7 

88.3 

97, I 

35 

1,099 

384 

( T riticum durii m ) , 

3 

279. 4 

98. I 

109. 9 

32 

I, 120 

393 

May 9 to Sept, 

4 

2S8. 8 

QQ- 7 

j iS. 6 

33 

I, 190 

411 

fertilized 

5 

291. 8 

gg- 5 

122. 0 

54 

1, 226 

418 

I 

6 

261. 7 

92. 2 

106. 2 

35 


406 

Alcan ^ 






h ”i±3r 

394 ±7 









2gi. 8 

102. 8 

loS. 6 1 

35 

1,056 

372 

Kubanka, C. I. 1440, 
May 9 to Aug. 21, 

S 

9 

272. 3 
290.3 

100. 6 

lOT. I 

107. 4 
loS. 8 

37 

35 

1, 067 

1, 076 

394 

375 

unfertilized 

10 

274. 8 

79- 3 

109. 4 

29 

If 375 

398 


II 

300. 2 

105. 7 

1 1 14. I 

35 

1, 080 

380 


12 

263. 2 

87. 6 

1 88. 4 

33 

1, 090 

336 

Mean 







.57i>±6 


j 

1 


I I ^4 ±3^ j 


CLIMATIC FACTORS 

The instrumental equipment for the measurement of climatic factors 
included maximum and minimum tliennometers and an air thermo- 
graph exposed in a standard shelter 4 feet above the ground surface, an 
anemometer, a psychrometer, a rain gauge, and an evaporation tank. 


1 Based ou pots i to 6 , unfertilized, wliich had the same exposure as pots 7 to 13, fertilized. 



6 


JouYfidl of A^Ytcultural RcscdYch 


Vol. Ill, No. I 


The sunshine, the wind velocity, the combined sun and sky radiation, 
the wet bulb depression, and the evaporation were automatically recorded. 
The results of some of these measurements, combined in 5-day periods 
for the sake of brevity, though not without sacrifice, are given in Tables 
III and IV. The discussion of the influence of climate on water require- 
ment has purposely been restricted, since such correlations as may 
exist can best be determined when discussed in connection with the 
results from other stations established for this purpose. 


TablB III- — Su7nmaTy of climatic conditions at Akron, Colo., in igi2 


Month. 


April, 


May, 


June. 


July 


August 


September. . 



Air temperature (“F.). 

^recipi' 

talion. 

Kvapo- 

ratiun. 

Wind 

veloty 

ity 

per 

hour. 

Days 

(Indusive). 

Average of— 

1 


Mini- 

mum. 


Vleans. 

Maxi- 

mums. 

Mini- 

mums. 

mum. 







Inches. 

Inches. 

MiUs . 

( I to 5 

48 

62 

33 

73 

29 


0. 82 

7 - 7 

6 to 10 

44 

60 

29 

6g 

23 

0. 26 

•71 

8*5 

II to 15 

44 

56 

30 

68 

26 

• SI 

•71 

14- 7 

16 to 20 

40 

49 

29 

54 

26 

•36 

•47 

9 - 5 

21 to 25 

46 

57 

32 

70 

27 

-03 

. 78 

9.6 

26 to 30 

49 

62 

35 

69 

32 

1*33 

1, 09 

9 - S 

( I to 5 

50 

67 

35 

76 

28 

■ 35 

.98 

la 4 

6 to 10 

53 

66 

4 t 

75 

34 

- 40 

.90 

8- 3 

It to 15 

44 

53 

36 

65 

32 


. 60 

8. 6 

16 to 20 

61 

77 

47 

83 

41 

Tr. 

.99 

6.9 

2 I to 25 

64 

78 

47 

84 

42 

Tr. 

I- 32 

7 - I 

26 to 31 

60 

77 

44 

92 

35 

I. 14 

2.31 

9-3 

I to 5 

64 

78 

49 

83 

45 


I. 32 

7-8 

6 to 10 

59 

69 

49 

78 

47 

. 41 

• 74 

8. I 

II to 15 

60 

72 

49 

84 

44 

1.03 

. 84 ■ 

4 - 5 

■ 16 to 20 

55 

65 

41 

78 

37 

I. 51 

1. 00 

4-3 

21 to 25 

66 

80 

50 

86 

43 


I. 21 

5 - 5 

26 to 30 

72 

88 

55 

89 

50 

.44 

I. 64 

6. 1 

I to 5 

66 

81 

49 

87 

46 

•03 

I. 12 

5 - I 

6 to 10 

73 

89 

55 

96 

5 ^ 

* 34 

I- 58 

6, I 

II to 15 

70 

86 

54 

92 

51 

. 01 

1.36 

5-6 

• 16 to 20 

69 

82 

55 

90 

50 

.72 

I. 06 

6 . I 

21 to 25 

73 

88 

59 

94 

55 

I. 63 

I. 38 

S' 5 

26 to 31 

69 

80 

57 

85 

53 

•85 

I. 12 

4. 1 

I to 5 

68 

79 

58 

84 

54 

. 16 

I. 04 

7 - I 

6 to 10 

65 

79 

50 

85 

48 

■32 

I. OS 

3 -S 

II to 15 

69 

83 

54 

89 

SO 

-38 

I- IS 

S' 2 

' * j 16 to 20 

68 

82 

53 

86 

51 

•56 

1. 04 

3 'C 

21 to 25 

7 ^ 

89 

56 

95 

52 


. I. 29 

4 'C 

[ 26 to 31 

72 

88 

56 

96 

53 

. 16 

I. 48 

S' I 

1 to 5 

70 

87 

54 

90 

47 


■ 1-39 

6.1 

6 to 10 

65 

80 

5 ^ 

91 

47 

•43 

1. 08 

7 ' ! 

II to 15 

51 

61 

38 

77 

32 

I. 26 

. 61 

5 -< 

■ ' 16 to 20 

51 

66 

■37 

81 

31 


. . 62 

6' ; 

21 to 25 

46 

59 

34 

71 

22 

. 02 

•54 

6. ; 

26 to 30 

43 

56 

32 

70 

26 

. 17 

. 41 

4. : 



Oct. IS, 1914 


Water Requirement of Plants 


1 


Tabi^JS IV . — Summary of climatic conditions at Akrout Colo., in JpJj . 


Month. 

Days 

(inclusive). 

Air tcmperatui 

Average oi — 

eCR). 

Maxi- 

mum. 

Mini- 

mum. 

Precipi- 

tation. 

Rvapo- 

ralion. 

Wind 

veloc- 

ity 

per 

hour. 

Means. 

Maxi- 

mums. 

Mini- 

mums. 

1913- 









Inr.hes. 

Inches. 

Miles, 


1 

to 

s 

49 

66 

31 

77 

21 

0. 02 

0. 82 

7-4 


6 

to 

10 

33 

46 

24 

73 

10 

•94 

, 78 

12.4 

April 

11 

to 

15 

45 

64 

29 

77 

18 


•31 

3-6 

16 

to 

20 

53 

69 

40 

74 

34 

■87 

.76 

7.2 


21 

to 

25 

44 

55 

34 

68 

27 

■36 

• 51 

II. 0 


26 

to 

30 

60 

78 

40 

84 

37 

I. 15 

7- 1 


I 

to 

5 

47 

58 

35 

69 

31 

Tr. 

• 72 

6.7 


6 

to 

10 

54 

68 

43 

81 

41 

.82 

,84 

8.9 

May 

II 

to 

IS 

55 

69 

43 

80 

3.3 


.86 

7-4 

16 

to 

20 

55 

70 

42 

80 

38 

Tr. 

-93 

7-6 


21 

to 

25 

62 

77 

46 

84 

39 

. 02 

• 99 

5 - 7 


26 

to 

31 

69 

86 

51 

91 

48 

. 06 

I. 50 

5-6 


I 

to 

s 

65 

81 

51 

87 

48 

. 26 

I- 15 

6. 2 


6 

to 

10 

57 

67 

45 

77 

37 

Tr. 

I. 07 

10-3 

June 

II 

to 

IS 

66 

81 

51 

91 

42 

. 16 

I. 17 

9. 0 

16 

to 

20 

71 

88 

54 

93 

52 

: Tr. 

; I. 27 

6.6 


21 

to 

2 S 

69 

86 

54 

89 

52 

- 51 

I ,33 

5-8 


26 

to 

30 

74 

91 

60 

97 

49 

.42 

2, 19 

10.3 


' I 

to 

5 

75 ; 

92 

56 

100 

S3 


1. 71 

7. 0 


6 

to 

10 

79 ; 

96 

60 

lOI 

56 


1. 88 

6.6 

Jtiiy 

II 

to 

IS 

74 

92 

56 

103 

46 

. 02 

1. 78 

6.8 

16 

to 

20 

68 

83 

56 

93 

53 

z. 12 

I. 27 

4. 8 


21 

to 

25 

66 

78 

56 

87 

53 

.61 

1. 01 

6. 8 


. 26 

to 

31 

67 

87 

49 

93 

43 

. 10 

1. 61 

5-0 


{ 1 

to 

S 

78 

95 

61 

98 

57 


I- 75 

5.8 



to 

10 

74 

90 

59 

97 

54 

•OS 

I- 54 

6. 2 

August 

1 II 

to 

IS 

73 

90 

59 

93 

56 

.81 

I. 23 

4-9 

16 

to 

20 

76 

93 

61 

95 

56 

.24 

1.38 

5-0 



to 

25 

73 

90 

57 

97 

53 


■ 1-58 

5-9 


{ 26 

to 

31 

75 

91 

59 

98 

54 

, 04 

; 1.83 

5-9 


f 1 

to 

5 

73 

90 

56 

92 

54 

- 17 

I- 37 

4-8 



to 

to 

68 

85 

53 

92 

48 

•45 

1. 27 

6. 7 

September. . . . 

I 11 

to 

15 

62 

79 

45 

86 

40 

. 10 

1.30 

7.6 


10 to 
21 to 
[ 26 to 

20 

25 

30 

S 3 

45 

50 

68 

59 

60 

1 

39 

32 

41 

87 

76 

70 

29 

27 

37 

Tr. 

•39 

•97 

.98 
. 61 

■ 51 

9. 2 
S-6 
4 - 7 


The months of June, July, August, and September, 1913, were all 
warmer than in 1912, the average difference in the monthly means being 
4° F. In only 2 of the 24 five-day periods into which these months are 
divided did the mean maximum temperature in 1912 exceed that of 
1913- The character of the two seasons is best reflected, however, in 
the evaporation graphs shown in figure 1. The evaporation for the two 
years was not essentially different up to the ist of June. From this 
time on the evaporation in 1912 averaged much lower than in 1913. 



8 


Journal oj Agricultural Research 


Vol. m. No. I 


The marked response of the plants to the different seasons is shown in 
the reduced water requirement in 1912. (SeeTables XXXII, pp. 36-38, 
and XXXIII, p. 39.) 

WATER REQUIREMENT OF VARIOUS CROPS 
WHEAT 


The water requirement of six varieties of wheat, including emmer, 
was measured at Akron in 1912. The results a’rranged in order of 
increasing water requirement based on dry matter are as follows: 


Variety of wheat 

Turkey 

Kharkov 

Kubanka 

Etnmer. 

Bluesteni 

Spring Ghirka, , . 


Water requirement 

364^6 

365^6 

394 ±7 

428 ±3 

45i±4 

457±3 



Fig. I. — Evaporation from a frec-w.aicT surface (tank) at Akron, Colo., in 191 1 and 151-’. Note the 
marked reduction in evaporation in 1912 after June 10, A volcauic eruption in Alaska occurred on 
June 6. 


The Turkey and Kharkov varieties (PI. Ill, fig. 6) were tested for 
the first time in 1912. These are winter varieties and were transplanted 
to the pots in the spring from field plats sown in the fall. They gave 
the same water requirement and appear to be about 10 per cent more 
efficient than the Kubanka (PI. Ill, fig. i), which has heretofore been 
the most efficient wheat tested as regards economy in the use of water. 
This comparison, however, ignores the small quantity of dry matter in 


Oct. IS, 1914 


Water Requirement of Plants 


9 


the plants at the time of transplanting. The three remaining varieties 
show somewhat greater differences than in 1 91 1 , and the order is reversed. 
The probable error of the water requirement of emmerin the 1911 exper- 
iments was abnormally high, so that the 1912 series (PI. Ill, fig. 4, 
and PI. VII, fig. 4) may be considered more nearly representative of 
the relative position of this crop. 

The water requirement of different varieties based on grain production 
is as follows : 


Varitly of wheat 

Emmer (including glumes) 

Turkey 

Kharkov 

Kubanka 

Emmer (without glumes) . . 

Spring Ghirka 

Bluestem 


Water requirement 

984 ±18 

995±22 

i,o64±6o 

I, iiT±37 

I, 243 ±23 

i,468i:34 

b 573^49 


In order to reduce the results obtained with emmer to a basis com- 
parable with the other varieties, the calculations should be made upon 
the weight of the grain without the glumes, which constitute about 21 
per cent of the total weight. WTien this is done, it will be seen that the 
water requirement of the different varieties based on grain production 
follows the same order as when based on the production of dry matter. 
The Turkey wheat again gives the lowest value for the water require- 
ment, although the Turkey, Kharkov, and Kubanka may be considered 
substantially in agreement when the errors of the experiment are con- 
sidered. The detailed results are given in Table 


Taki.h — Water requirement of di^creni 'i'arietks of wheat at Akron, Colo,, in 

and 


Plant anil perioil of i;rowtli. 


igi2. 


r 


Kubanka, C. I. 1440 
{Triiicum durum). 
May 9 to Sc]it. 3 . . . . 


]\Iean 


Marvel Bluestcm, C. T. 
30S2 (T T i t i c u m 
aesiivtim), May ii to 
Aug. 2S 


Mean, 


Water reqinrement 


Pot 

Xo. 

matter. 

Grain. 

Water. 

Grain. 

b.ased 0 


Grain. 

Dry maTter. 


(irams. 

Gratns. 

Kihs. 

Per cent. 



T 

270. 0 

ToS. 2 

9 S- ^ 

40 

879 

352 

2 

252- 7 

88. 3 

97. r 

35 

i,ogg 

3^4 

3 

279.4 

98. I 

109. g 

32 

I, 120 

393 

4 

28a. 8 

99 - 7 

Ilk 6 

33 

I, 190 

411 

5 

291, S 

99 - 5 

122. 0 

31 

I, 226 

41S 

0 

261. 7 

92. 2 

106. 2 

35 

b 152 

406 







20_1 7 









31 

2S6. 2 

' 74 - 2 

126. 3 

' 26 

1, 701 

441 

32 

533-0 

93 - I 

147. 4 

28 

1, 582 

443 

33 

310. 8 

87.9 

M 5 - 7 

28 

1 , 958 

469 

34 

29S. 8 

77. 2 

134- 3 

26 

1, 740 

450 

35 

321. 4 

102. g 

M 9 - 5 

32 

1 5 452 

4^5 

0^ 

334. 3 

III. S 

M 5 ' 7 

33 

1^303 

439 

4 >I -4 




1 

1 U i 




lO 


Journal of Agricultural Research 


Vol. Ill, No. 


Table V. — WaUr requirement of different varieties of -wheat at Akron, Colo., in igi2 
and ipj 3— Continued 


Plant and period of growth. 

Pot 

No. 

Dry 

matter. 

Crain. 

Water. 

Grain. 

Water requirement 
based on — 

Grain. 

Dry matter. 

1912. 

Kharkov, C. I. 1583 
( T riticum aes tivurn) , 
Apr. 27 to Aug. 28. . . 

Mean 

37 

38 

39 

40 

41 

42 

Grams. 

365- 6 

347 - 3 
360. 0 
384- 9 
326.9 
310. 7 

Grams. 

91. 6 
131- 3 
128. 7 
138. I 
124.4 

1 19. 2 

Kilos. 
138. 0 
122. 0 
141. 6 
135-6 
121 5 
io6 I 

Percenl. 

25 

38 

36 

40 

38 

38 

1.505 

930 

Ij 100 

982 

978 

890 

377 

351 

394 

353 

372 

342 

I, o64±6o 

36 s ±6 

Turkey, C. I. 1571 
{Triticum aesHvum), 
Apr. 27 to Aug. I . . . 

43 

44 

45 

46 

47 

48 

344. 4 
328. 4 
242. 7 
308, 0 
245 ' 9 
274.4 

I 2 I. 2 
II2. 4 
86. I 

1 19. 6 
97 - 7 
100. 8 

132 5 
120. 0 
85. 6 
106. 7 
95 - 2 
95-4 

35 

34 

35 

39 

40 

37 

I, 092 

I, 070 

995 

892 

974 

946 

385 

365 

353 

346 

387 

348 

995 ±22 

364^:6 

Spring Ghirka, C. I. 
1517 (Triticum aes- 
tivum), May ii to 
Aug. 12 

f 55 
56 

I 57 

58 

59 

1 60 

266.8 
263.3 
264. 6 
275- 9 
297. 9 
314. 7 

74-4 

81. 0 

82. I 
90. 2 
94. 2 

105. 2 

122. 5 
120. 6 
126. 3 
125. 6 

131-5 

141. 6 

28 

31 

31 

33 

32 

33 

1,64s 

1,489 
b 540 

1,393 

1.395 

1,347 

459 
- 458 

477 

456 

442 

450 

Mean 

I, 468 ±34 

457±3 

Etnmer, C. I. 2951 
( Triticum dicoccu m), 
May II to Aug. 12 . . 

Mean 

61 

62 

64 

65 

1 66 

351 - 5 
3M‘ 7 

352 - 8 
340 - 5 
3.58- I 
343-0 

155-6 

142-3 

146. 1 
143. 8 
159- 7 
149. 0 

145 - I 
132- 5 

158. Q 

147. 8 

I 51. 6 
146. 3 

44 

45 

41 

42 

42 

43 

932 

9.30 

I, 0^ 

I, 028 

950 

982 

413 

421 

448 

434 

423 

426 

984 ± 18 

428±3 

Kubanka, C. I. 1440 
(Triticum durum), 
May 23 to Aug. 13 . . . 

73 

74 

75 

76 

77 

78 

294. 8 
273- 4 
257.0 
304. 2 
2 53-3 
299. 6 

io6. 5 
lOI. 4 
97. I 

1 16. 2 
93-8 
1 16. 8 

150- 3 
185-9 
122. 4 
156. 0 
121. 3 
ISO. 2 

36 

37 

38 

38 
37 

39 

1,411 

ri 340 

I, 261 
*,342 

I, 293 

I, 286 

510 

497 

476 

513 

479 

502 

I, 322 ±l 6 

496 ±5 








Ohly one variety of wheat, the Kubanka, w’as included in the measure- 
ments of 1 91 3. This variety gave a water requirement 26 per cent above 
the 1912 ratio and 19 per cent above the 191 1 ratio. The water require- 
ment on the basis of grain production was 19 per cent higher than in 
1912 and 1 1 per cent higher than in 191 1. 



Oct 15, 1914 


Water Requirement of Plants 


1 1 


OATS 


The four varieties of oats employed in the water-requirement tests in 
1912 were the same as those used in the 1911 experiments. The water 
requirement in 1912, based on the total dry matter produced, was as 
follows : 


Variety of oats 

Canadian 

Swedish Select. 

Burt 

Sixty-Day 


Water requirement 
399±6 

423 ±5 

449 ±3 

49^ ±13 


The Canadian again proved to be the most efficient of the varieties 
tested. The differences exhibited by the first three varieties in the 
list are practically the same as in 1911. 

Much trouble was experienced in obtaining a stand of Sixty-Day 
oats. The germination was very poor and a second and even a third 
planting failed to give a good stand, as is shown by the variations in 
the yield of the different pots. (Table VI.) This is, perhaps, the cause 
of the higher water requirement obtained for Sixty-Day oats, which 
in 1911 ranked next to the Canadian in efficiency. 

The water requirement of the different oat varieties, based on grain 
production in 1912, was as follows: 


Variety of oats 
Sw'edish Select. 

Sixty-Day 

Burt 

Canadian 


Water requirement 
■ ■ - . I, I03± 18 
1 , i72±133 

- ■ - ■ 1,224±S5 

. . . . I, 4i6± 119 


The probable error is high in all the determinations, except in the 
case of the Swedish Select (PI. Ill, fig. 5), and the relative order 
of the varieties is consequently of little significance. It is, however, of 
interest to observe that the Canadian variety is the least efficient in the 
use of water from the standpoint of grain production, which is in accord 
with the 1911 experiments. 

Swedish Select and Burt oats were also included in the 1913 measure- 
ments at Akron. On the basis of dry matter produced, the two varie- 
ties were equally efficient in the use of water. In the measurements 
of 1912 and igi i these two varieties gave only slight differences, the 191 1 
and the 1912 results being in accord when the probable errors are con- 
sidered. On the basis of grain production, the Burt was the more effi- 
cient in 1913, and the Swedish Select in 1912 and in 1911. No real 
differences of importance are shown in these two varieties when the meas- 
urements of the three years are considered. 



12 


Journal of Agricultural Research 


voi. irr. No. 


Table YI, — Water requirement of different varieties of oats at Akron, Colo., in igT2 and 

^ 9^3 


Plant and period of growth. 

Pot 

No. 

Orv' 

matter. 

Grain. 

Water. 

Grain. 

Water reciuirement 
bawjd on— 

Grain. 

Ory matter. 

1912. 

Sixty Day, C. I. 165 
(A vena sativa), May 

15 to Aug. 23 

Mean 

67 

68 
6q 

70 

71 

72 

Grams. 
206. 5 
287. 7 
270. 9 

93 - 9 
274. 7 
248. 9 

Gramf, 
72.8 
147. 9 
107.3 

Kilos. 
T19. 9 

13 1. 8 
133 - 6 
41. 6 
’129. 5 
124. 7 

Per cent. 

36 

51 

40 

1=645 

892 

T, 245 

580 

458 

493 

444 

472 

501 

143 - 4 

52 

904 





T, T 72 il 33 

491 ±13 

Canadian, C. I. 444 
(/h'etia sativa), May 
17 to Sept. 16 

73 

74 

7 5 

76 

77 

78 

227, I 
302. I 
233- 5 
276. 0 
YS8.3 
250. 0 

80. 9 

1 18. 7 
50- 4 
79.8 

91. I 
126. 7 
89. I 
107. 8 
59 - 3 ' 
107. 0 

36 

39 

22 

29 

I, 125 

1, 068 

1, 767 

1=350 

401 

419 

382 

390 

375 

428 

Mean 

60. 3 

^4 

I, 769 

I, 4 t 6 J:;ii 9 

399 ±6 


7 Q 

352. 8 

138.8 

^ 53 - 5 

39 

I, loO 

435 


8d 

339 - 9 

no. 5 

T58. 4 

33 

I, 433 

466 

Burt, C. I. 293 

81 

2qq. 3 

93 - 8 

133- 8 

31 

1,448 

453 

sativa), May 15 to 

82 

344 - 5 

132. 9 

130. Q 

39 

1=135 

438 

Aug. 23 

S3 

351 - 5 

147. 8 

160. 3 

42 

1 , 08 5 

456 


84 

363-8 

143-3 

162. 7 

.39 

1, 135 

447 

ytean 




i 

i 

I, 224±55 

-149 ±3 


83 ' 

402. 2 

T67. 7 

i 

167. 2 

1 

42 

‘ 997 

4x6 

Swedisli Select, C. I. j 

86 

87 

395 - 7 
409- 5 

145. 9 

^ 55 - 9 

1 7 1. 5 

I 7 I. 2 : 

38 

1 I, 176 

I, 098 

434 

418 

134 {Avcna sativa), 

! 88 

412. 2 

YS 2 . 9 

16.}. 0 

37 

1=073 

398 

May 17 to Aug. 23 ; 

; 86 

389- 8 

145- 9 

:6q. 7 

37 

I, 163 

435 


1 90 

366. 8 

i 44 - 5 

161. 0 

39 

1= 113 

439 

Mean ' 






1 , 1 03 ± 1 8 

- 123^:5 

1913- 

! 

f 79 

265- 5 

84. 2 

171. 4 

32 

2=035 

646 


80 

250. I 

S3. 0 

164. 2 

33 

1=979 

656 

Stvedi.=5li Select, C. I. 

8r 

1 262. 4 

77. 4 

X 58. 5 

29 

2,049 

604 

134 (Avena sativa), 

! 82 

296. 7 

106. 9 

U 5 - 3 

36 

1, 640 

591 

May 23 to Aug. i. . 

i 83 

286. T 

lOI. 4 

1 74 - 3 

33 

1. 719 

609 


1 84 

2gi. 9 

95 - 0 

174. 0 

33 

1,831 

596 

Mean 



I 



1,8764:55 

! 6 i 7-±9 


85 

243 - 7 

93 - 4 

14S. 8 

38 

1, 594 

6m 


; SO 

245. 6 

loi. 8 

151. I 

41 

I, 484 

616 

Burt, C. 1 . 293 {Arena 

87 

240. 4 

87. 6 

^56- 5 

36 

1, 787 

650 

sativa). May 23 to 

: 88 

255. s 

89.3 

157-9 

35 

1,758 

614 

jLiiy 25 

89 

230. 0 

94 - 7 

155- 7 

38 

I, 644 

633 


1 90 

254. 9 

94 - 5 

i l 9 - 3 

37 

I, 580 

586 







I. 641 ±33 

! 6i7'.[:5 

1 


I 

1 







Oct. IS, 1914 


Water Requirement of Plants 


13 


BARL,EY 


Barley is the most uniform in water requirement of the small-grain 
crops which the writers have tested. The four varieties grown at Akron 
in 1912 showed only slight differences in their water requirement. The 
results obtained, based upon the production of dry matter, were as follows: 


Variety of barley 

Beardless 

Beldi 

White Hull-less. . 
Hannclien 


Water requirement 

403 ±8 

4i6±4 

439 ±i 

443 ±3 


These same varieties were also tested at Akron in 1911 and were 
found to be in practical agreement as regards their relative water require- 
ment. The mean value of the water requirement was 27 per cent 
higher ill 1911 than in 1912. 

The results obtained with barley when the water requirement is 
based on grain production are less uniform than when the total dry mat- 
ter is employed. Reference to Table VII will show that this is often 
due to a single pot which for some reason fails to set grain as abundantly 
as the rest of the series. The Beldi, a dwarf variety, showed the highest 
efficiency in the use of water in grain production. The White Hull-less 
(PI. Ill, fig. 2) has a water requirement slightly above the other 
varieties, even when a correction is made for the naked character of 
the grain. 


Table — Water requirement of different varieties of barley at Akron, Colo., in igi2 


Plant and period of growth, i 

Pi A 
-No. 

j r>ry 
matter. 

Gram. 

Water. 

Grain. 

i Water requirement 

based on — 

Grain. 

Dry matter. 

1912. 


Grams. 

Grams. 

K. dos. 

Per cent. 




91 

5 

L4L. 7 

138. I 

47 

974 

45S 

Hannchen, C. I. 

92 

282. 9 

ri6. 6 

127. 7 

41 

1=095 

452 

{Hordeuni dislkhon ). 

93 

281. I 

ro 3 - 5 

124. 2 

37 

I, 200 

442 

May 16 to Aug. 28. . . 

94 

300- 3 

^ 37 ' ^ 

133-3 

46 

972 

444 


95 

309.2 

145 ' 5 

134- 9 ; 

47 

926 

436 


96 

3 <^- S 

152. 0 

130.9 

49 

8 60 

424 

Mean 







1 r ±3 


' 97 

230- 5 

roi, 5 

93-9 1 

44 

925 

407 

Beldi, C. I. 190 (//or- 

98 

240. I 

107. 0 

98- 5 

45 

920 

410 

deztm vulgare), May 

1 99 

243. 0 

109. 2 

99 - 5 : 

45 

910 

409 

16 to Aug. 12 

100 

189. 4 

8r. 3 

82. I ' 

43 

I, 010 

434 


10: 

223. 8 

loi. 6 

97.0 

45 

954 

434 

i 

^ 102 

236. 5 

103. I 

95 ' 5 

44 

926 

404 

Mean ! 






941 -J- 10 

416 i 


f n >3 

271. 2 

95-3 

1 19. 7 

35 

' ij 25^ 

! 441 

White Hull -less, C. I. ^ 

104 

276. 0 

97. I 

121. 4 

35 

250 

440 

595 {Hordeum vul- \ 

105 

273- ^ 

95-6 

1 19. 4 

35 

1= 249 

437 

gare), May 16 to j 

1 106 

268. 8 

92. 9 

1 19. 7 

35 

I, 2S9 

445 

Aug. 12 

107 

273.8 

99 - 5 

1 18. 4 

36 

I, 190 

433 

! 

[ 108 

299. 7 

no. 0 

131. 6 

37 

197 

1 439 

Mean : 






T > ?n •- T r 1 

1 '*n -1- T 

i 





1 4jy:ri 



Journal oj Agricultural Research 


Vol. Ill, No. r 




Table VII . — Water requirement of different varieties of barley at Akron, Colo., in igi2 — 

Continued 


Plant and period ot erowth. 

Pot 

No. 

Dry 

matter. 

Grain. 

Water. 

Grain. 

Water requirement 
based on — 

Grain. 

Dry matter. 

19T2. 

Beardless, C. I, 716 
( Ho rdeum vulgar e) , 
May 16 to Aug. 23. . . 

109 

110 

111 

112 

114 

Grams. 
II2. 0 

144. I 

276.3 
227- 5 
210. 5 

291.3 

Grams. 
20. 7 
2Z. 9 

135 “ 7 ' 

92. 2 

63-9 

120. 2 

Kilos. 
49. 2 
56. I 
III. 6 

93-8 
87.2 
103. 7 

Per cent. 
18 
IS 
49 

40 

30 

41 


439 

389 

408 

412 

414 

356 


823 

I, 017 

I, 364 

862 

r, 017 ±83 

403 ±8 



1 




RYE 

The measurement of the water requirement of spring rye at Akron 
in 1911 showed a surprisingly high figure — 54 per cent above that of 
Kubanka wheat. The 1912 measurements (Table VIII) gave 496 ±9 
for the water requirement of rye when based on dry matter and i ,802 ± 62 
when based on grain produetion. The 1912 (dry matter) ratio is thus 
about 26 per cent above Kubanka wheat, a marked increase in the rela- 
tive efficiency in comparison with the 1911 ratio. In fact, rye exhibited 
the greatest reduction in water requirement of all the crops tested in 
1912. 

A consideration of the water requirement of crops grown out of season 
in 1911 showed that rye was unusually efficient during the cool fall 
period. This result as well as the increase in efficiency in 1912 suggests 
that rye may be unusually responsive to climatic conditions and that 
it is relatively better adapted to low temperature than the other small 
grains. 

Table VIII . — Water requirement of rye at Akron, Colo., in igi 2 


Plant and period of growth. 

Pot 

No. 

Dry 

matter. 

Grain. 

Water. 

Grain. 

Water requircmcj^ 
based on — ^ 

Grain, 

Dry matter. 

1912. 

Rye, spring, C. I. 73 
{Secale cereah ), May 
16 to Aug. 23 ' 

116 ' 

117 

118 

119 

120 

; Grams. \ 
\ 210. 6 ! 
216. 4 
179. 2 
248. 6 

234^ 5 
254- I 

Grams. 

57- 8 

65. I 
K2. 6 

65. 8 
54“ 7 
75-6 

Kilos . ; 

96. 2 
118. 8 i 

84-3 ' 

123.3 ' 

120. T 
124. 6 

Per C 4; nt . '■ 

27 

30 

29 
26 

23 

30 

1, 664 

1,825 

1,603 

1,874 

2, 195 

1,649 

457 

549 
, 470 

496 

512 

490 


I, 802 ±62 

496 ±9 





! i 



Oct. IS, 1914 


Water Requirement of Plants 


15 


RICE 

Rice was grown for the fiilst time at Akron in 1912. The crop was slow 
in becoming established, and the growth period was relatively long. No 
grain was produced. The water requirement based on dry matter was 
5 1 9 ± 1 3 (Table IX) . It thus appears that rice, although a crop normally 
grown with an abundant water supply and in a relatively humid climate, 
is about as efficient in the use of water as rye. Its relative position 
might be materially changed if the tests were made in a warmer climate. 

Rice was also included in the 1913 measurements (PI. VII, fig. 3). 
The stand was good and the growth was uniform and luxurious, but the 
season was too short to produce grain. The water requirement in 1913 
was 744 ±17, or 43 per cent higher than in 1912. 

TABr,e IX . — Water requirement of 'rice at Akron, Colo., in igiz and iqtj 


Plant and period of growth. | 

Pot No. 

Dry mat- 
ter. 

Water. 

Water require^ 
meiit on 

dry matter. 

1912. 


Grams. 

Kilos. 




248. 4 

133 - 5 

538 


152 

253- I i 

141. 2 

558 

Rice, Honduras, C. 1 . 1643 (Oryza sativa). 

153 

232- 5 1 

127. 4 

.S48 

May 27 to Sept. 23 

154 

168. 9 1 

9 °- 5 

536 • 


155 

194. 0 

94. 8 

488 


156 

225. 6 

1 100. 0 

445 

Mean 









5i9± 13 

1913- 





i 

157 

276. 7 

218. 2 

790 


158 

261. 7 

211. < 

809 

Rice, Honduras, C. I. 1643, June 12 to Sept. ■ 

^59 

230. 2 

176. 9 


16 i 

160 

274. 8 

186. 6 

6S0 


161 

294. S 

204. □ 

692 


162 

298. 7 

215, 8 

722 

Mean 




'’ 44 rbi 7 

i i 





Fl.AX 

Flax was included in the water-requirement measurements at Akron for 
the first time in 1913. Its water requirement was found to be very 
high, 905 ±25 based on dry matter and 2,835 ±52 when based on seed 
production. It will thus be seen to have a water requirement as high or 
higher than any of the legumes tested in 1913. This is in accord with 
the measurements made by Leather (1911, p. 270). in India, in which flax 
was exceeded in water requirement only by chick-peas and rice. At 
Akron in 1913 flax required 22 per cent more water than rice. The 
detailed results are given in Tabic X. 



i6 


Journal of Agricultural Research 


Vol. ni, No. 1 


Table X . — Water requirement of jlax at Akron, Colo., in igi^ 


Plant and p€riod ol growth. 

Pot 
, No. 

Dry 

matter. 

Gr^. 

Water. 

Grain. 

Water reqnirement 
based on— 

Grain. 

Dry matter. 



Grans. 

Grans, 

A' ilos. 

Per ctnU 




127 

! 189. 0 

64. 9 

184. 8 , 

34 

2,845 

978 

Flax, North Dakota, 

128 

154-7 

53-0 

143 - 4 

34 

2,704 

927 

No. 155 {Linum 

I 2 Q 

209. 3 

77. z 

210. 6 

37 

2, 728 

1,006 

usitaii ss imum), 

130 

93 - 0 

33-9 

76-3 

26 

3 ) 190 

811 

June 3 to Sept, i . . . . 


116. 7 

32. 5 

1 93-9 

i 28 

, 2, 886 

804 


132 

187. 8 

63- 7 

1 ^69- 2 

1 34 

1 2,658 

902 

Mean 





1 

2, 835±52 

i 

9 < 55 ± 2 S 





1 



SUGAR beets 

The water requirement of the sugar beet was again measured at Akron 
in 1912, The ratio 321 ±8 was obtained on the basis of total dry matter 
and 524^23 on the basis of the dry root (Table XI). This is about 15 
per cent below the 1911 value, a reduction in water requirement similar 
to that shown by the other crops tested during the two seasons. The 
sugar beet is an efficient plant in the use of water, being the equal of the 
corn group in this respect. 

T.\blE XI. — Water requirement of sugar beets at Akron, Colo., in Tgi2 


Plant and period of 
grywth. 

Pot 

No. 

Dry 

matter. 

Rcx)ts, 

Water. 

Roots. 

Water requirement based 

Dry roots. 

Total dry 
matter. 

1912. 

Sugar beet (Beta vul- 
garis), June 9 to , 
Oct. 12 ............ . 

169 

170 

171 

172 

173 

174 

Grams. 
257- 4 
^ 75-0 

1 173-3 
163.6 
196. 8 
164. 5 

Grans. 
189. 7 
93 - 6 
100. 0 1 
107- 3 1 
123.0 1 
97 - 7 

Kilos. 
76. 0 

53 - 7 ' 
49. 6 
52 - 5 ' 
68. 7 
58.9 

1 

Per cent. 

74 

S 3 

S8 

66 

63 

60 

401 

595 

496 

489 

558 

603 

29s 

318 

286 

321 

3^9 

Mean j 

524±23 

32i±8 







COTTON 

Cotton was tested at Akron for the first time in 1912. Numerous 
bolls set, though none opened. The plants grew slowly during the first 
part of the season, owing probably to the cool nights. The observed 
water-requirement ratio was 488^ 14 (Table XII). 



Oct- IS. I9J4 


Water Requirement of Plants 


17 


TabliS XII. — Water requirement of cotton at Akron, Colo., in igi2 and igi^ 


riant and period of growth. 

^ Tot No- 

Dry 

matta. 

Water. 

Water require- 
ment based 
on dry matter. 

1912. 

1 

Grams. 

Kilos. 



i8r I 

38- 9 

19. 2 

494 


182 

32. 0 

18-5 1 

578 

Cotton, Triumph {Gossypiuni hirsuium), 

1S3 1 

67. 4 

27. I 

402 


184 

! 61. 4 

28. 2 

459 



185 

51.6 

25. 2 

488 


186 

62. 4 

31 - 5 

505 

Mean 




488 ±14 





1913 - 

163 

237-5 

172. 4 

726 


164 

184-3 

115. 6 

627 

Cotton, Triumph, May 29 to Sept. r6 

165 

247. 4 

166. 1 

671 


166 

249. 6 

160. I 

642 


167 

161. 4 

106. 4 

660 


168 

187. 0 

115- 4 

617 

Mean 




657 ±ii 






The same variety was also included in the 1913 measurements. (PI. 
VII, fig. I.) The planting was made earlier, and a much larger growth 
was obtained. The water requirement was 657±ii, or about one-third 
higher than in 1912. In this connection it should be stated that at 
Akron cotton is far north of its natural range, which may have increased 
its relative water requirement. 


CORN AND TEOSINTE 


Six varieties of com {Zea mays) were tested at Akron in 1912 (PI. 
VII, fig. 5). Three of these varieties, Northwestern Dent (PI. IV, 
fig. i), Iowa Silvermine, and Esperanza, had also been used in the 1911 
experiments. The three new varieties were furnished by Mr. G, N. 
Collins, of the Bureau of Plant Industry, and represent widely different 
strains. The Hopi variety (PI. IV, fig. 2) is grown by the Hopi 
Indians in northwestern New Mexico (Collins, 1914); China White is a 
va? 5 ety from near Shanghai, China; while Taguna was originally from 
the State of Chihuahua, Mexico. The water requirement of each variety 
tested in 1912, based on tiie production of dry matter, is as follows: 


Variety of corn 

Espenmza 

Northwestern Dent, 

Hopi 

Daguna 

Iowa Silvermine . . . 
China White 


Water requirement 

239±3 

280 ±10 

285±7 

295±6 

302±7 

3i5±7 


The Esperanza, as in 1911, leads all the varieties, so far as efficiency 
in the production of dry matter is concerned, and ranks with the sor- 
60300®— 14 2 



i8 


Journal of Agricultural Research 


Vol III, No. 1 


ghums in this respect. The differences exhibited by the remaining varie- 
ties are without significance when the limitations imposed by the probable 
errors are considered, although the quick- maturing Northwestern Dent 
and Hopi varieties appear to be slightly more efficient than the others. 
The detailed data are given in Table XIII. The pollination was not 
adequate to give representative grain yields. 

Five varieties of com and one of teosinte were included in the 1913 
measurements. The water requirement of each variety, based on the 
production of dry matter, is as follows : 


Variety of corn or teosinte 

Indian Flint com 

Hopi com 

Teosinte, Durango 

Northwestern Dent com. 
Bloody Butcher com . . . . 
China White com 


Water requirement 

342±5 



39o±ii 

399±i2 

405±7 

4i5±4 


The most efficient varieties were the Indian Flint (PI. VI, fig. 5), 
a small variety grown by the Indians of northern Michigan, and the 
Hopi, another dwarf Indian variety. Teosinte, Northwestern Dent com, 
and Bloody Butcher, a local variety of corn grown near Wray, Colo,, 
showed only slight differences. The China White, as in 1912, proved to 
be the least efficient of all the varieties tested, having a water require- 
ment 20 per cent above that of the Indian varieties. 

In 1912 the water requirement of the Northwestern Dent com was in 
practical agreement with that of the Hopi, while in 1913 the Hopi gave 
a considerable lower value. The China White required 32 per cent more 
water in 1913 than in 1912; the Northwestern Dent, 42 per cent; and 
the Hopi, 23 per cent. 

The water requirement of certain com hybrids was also measured at 
Akron in 1912 and 1913. The mean water requirement of each strain 
has been included in the tables in the summary (Tables XXIX to XXXII). 


TabLS XIII , — Water requirement of different varieties of corn and teosinte at Akron, 
Colo., in igi2 and jgi;^ 


Plant and period of growth, j 

Pot 

No. 

i 

i 

I Dry 
matter. 

1 

1 

> Grain. 

1 

i 

: W’atcr. 

Grain, 

Water reijui 
based 0 

1 

Grain. 

irement 

n— 

Dry matter. 

i 

1912, 

Cora, Northwestern 
Dent {Zea mays), 
June 9 to Sept. 16. . . 

r 277 
278 

1 279 
\ 280 
i 281 ; 
[ 282 

; Grams. 
299. 0 

344- 2 
368. 5 
649. 0 
440. 0 
491. 0 

: Grams. 
18. 1 
53-9 

66, I , 

234-4 i 
lOI. 5 
117. I 

Kilos. 
102. 6 
100. 4 

103 - 5 

161. 1 

III. 3 

126. 1 

Per cent. 
6 
16 
18 

36 

23 

24 


343 

292 

286 

248 

253 

257 

280 ± 10 











Oct. 15. I9t4 


Water Requirement of Plants 


19 


TablB XIII . — Water requirement of different varieties of corn and teosinte at Akron, 
Colo., in IQI2 and ipij — Contitiued 


riant and period of growth. 


19 IZ, 

Com, Iowa Silvermine 
(Zea mays), June 8 to 
Sept. 26 


Mean. 


Com, Hopi (Zea mays), 
June 12 to Sept. 26. 


Mean. 


Pot 

No. 


Com, China White 
(Zea mays), June iz 
to Sept. 26 


Mean. 


Com, Laguna (Zea 
mays), July 2 to 
Sept. 26 


Mean. 


Com, Esperanza (Zea 
mays), June 12 to 
Sept. 26 


Mean 

19^3- 

Com, Bloody Butcher 
(Zea mays), June 7 
to Sept. 13 


Mean. 


Com, Indian Flint 
(Zea mays), June 7 
to Aug. 27 


Mean. 


283 

284 

285 

286 

287 
28S 


295 

296 

297 

298 

299 

300 


265 

266 

267 

268 

269 


2 89 

290 

291 

292 

293 

294 


247 

248 

249 

250 

251 

252 


2$3 

254 

255 

256 

257 

25« 


•^rams. 

596.0 
403. 7 
399- 7 
441. 5 
477-0 
437- 2 


433-0 
519- 5 

516.8 

415.8 

330.9 

364. 7 


243- 5 
577-0 
319,0 
524- 5 
660, 9 
401. 5 


376. 6 
261. 2 
268. 9 
448. I 
457- 4 
429. 2 


492.3 

574- 7 
563- 7 

510. 7 


411. 5 
485. 4 
456. 6 
501.9 
499- 4 
456. 8 


333-4 
397- 9 
380. 6 
292. o 
335- I 

380. 3 


123.4 

163-3 

161. 7 
loi. 6 
135- 2 
182, 6 


Kilos. 

167.9 

129.9 
133-4 
129. 6 

135- 6 

128. 9 


132-7 

140. 3 
131. I 
113- 4 
100. 2 
III. 3 


84. 3 
184. 6 
97- I 
173-9 
179. 6 
126. I 


112. 4 
83.8 
84. o 
124.4 
127. 8 

119-4 


1 14. 3 
133- 7 
141. 7 
122. 7 


174- I 
201. 5 
188. 6 
193.0 
183.6 

195-4 


1 14. 9 

130.5 

120. 6 
108. 2 
1 18. 7 

128.6 


Water requirement 
based on — 


931 

800 

746 

1.064 

878 

704 


854±39 


2S2 
322 
334 
294 
284 
_29S 
302 ±7 


307 

270 

254 

273 

303 

305 

285±7 


346 

320 

304 

331 

272 

3U 

3iS±7 


298 

321 

313 

278 

279 
278 


2g5±6 


232 

233 
2^2 
240 


239±3 


423 

41S 

413 

3S5 

368 

428 


405 ±7 


34S 

328 

317 

370 

354 

342 ±5 



20 


Journal of Agricultural Research 


Vol. Ill, No. I 


TabItB XIII. — Water requirement of different varieties of corn and teosinte at Akron, 
Colo., in igi2 and — Continued 


Plant and period of growth. 


'913- 

Corn, Northwestern 
Dent {Zea mays), 
June 7 to Sept. 6. . . , 


Mean. 


Com, Hopi {Zea mays), 
June 14 to Sept. i6. 


Mean. 


Cora, China Wliite 
{Zea mays), June 7 
to Sept, 16 


Teosinte, Durango 
( Euch laena mexi- 
cana), June 14 to 
Sept. 16 


Pot 

No. 


283 

284 

285 

286 

287 
2SS 


313 

314 

315 

316 

317 

318 


301 

302 

303 

3°4 

305 

306 


289 

290 

291 

292 

293 

294 


Grams. 

35 ^- 2 
392. 3 

336- 6 

285. 9 

389. 9 

382. o 


346. 7 

400. o 
472. 5 
417. I 

405-3 

6ig. 6 


554. 9 

487.5 

492. 6 
589. 2 
478. 7 

523- I 


616. 4 

534 - 5 
624. 5 

567-3 

520.0 

421.4 


131. 6 


1 17- 5 

100. o 


Kilos. 

153- 7 
142. 9 
136.6 
128. 7 
141.4 

143-4 


1 18. 8 

135- 8 

170. 2 
147. o 
163. 4 
185. 4 


228. 2 
210. 4 
202. 3 
228. I 
198. 7 
226. 6 


234- 7 
211. 6 
194.0 
231. 5 
214.4 
183. 2 


Water requirenient 
based on — 


I, 20? 

I, 434 


I, 24i±77 


436 

364 

406 

451 

563 

375 

399±T2 


343 

340 

360 

352 

403 

300 


350 ±8 


4? I 

432 

4II 

387 

415 

433 


4T5 ±4 


380 

396 

310 

408 

412 

435 


390±ii 


SORGHUM 


The investigation of the water requirement of the sorghums (Table 
XIV) is of special interest, owing to the marked efficiency exhibited by 
this group of plants in the use of water. The eight varieties grown at 
Akron in 1912, together with the water requirement based on the pro- 
duction of dry matter, follow: 


Variety of sorghom 

Brown kaoliang 

Red Amber . 

Minnesota Amber 

Milo 

White durra 

Blackhull kafir 

Dwarf milo 

Sudan grass 


Water requirement 

223±i 

237±4 

Z39±2 

249±3 

2SSi3 

259±S 

273±4 

359±2 



Oct. IS. I9U 


Water Requirement of Plants 


21 


The Brown kaoliang gave the lowest water requirement. Red Amber 
and Minnesota Amber, forage varieties of sorghum (PL IV, figs. 4 
and 5), gave practically the same ratio, which is but slightly higher than 
Brown kaoliang. 


TablR yilV.— Water requirement of different sorghums at Akron, Colo., in igi2 and zgz^ 


Plant and period of growth . 

Pot 

No. 

Dry 

matter. 

Grain. 

Water, 

Grain. 

Water requirement 
based on— 





Grain. 

Dry matter. 

1912. 

Red Amber, S. P. I. 
17543 (Andropogon 
sorghum), June 9 to 
Sept. 27 

253 

254 

255 

256 

257 

258 

Grams. 
400. 5 
541 - 7 
592. 0 
660. 5 
564- 0 
714. 2 

Grams. 
43 - 8 
41. 5 
58. r 
95 - 4 
44. 3 
93 - 5 

Kilos. 
103. I 

133.8 
135 - 5 

144.8 

135- ^ 

161. 0 

Per cent. 
11 
8 
10 

14 

8 

13 

2,351 

3, 221 

2,331 

I, 518 

3,050 

I, 722 

258 

247 

229 

219 

240 

226 

Mean 















237 ±4 

Minnesota Amber, A. 
D. I. 341-13 {Andro^ 
pogon sorghum), 
June 9 to Sept. 26 . . . 

247 

248 

, 249 

250 

251 

252 

666.6 
370.6 
S 43 - 0 
461. 3 
456. 6 

425-3 

272, 6 
139-9 
218. 4 
168. I 
195- 7 

163.3 

151. 2 
89. 6 
128. I 
no. 6 

1 10. 3 
103. 6 

41 

38 

40 

37 
43 

38 

554 

64 s 

586 

658 

564 

634 

227 

242 

236 

240 

242 

244 

Mean 






X 1 

239±2 







7 -L ^5 

Milo, Dwarf, S. P. I. 
24970 {Andropogon 
sorghum), June 9 to 
Sept. 27 

' 217 
21S 

219 

220 

434 - 5 
370. 2 
334-3 
403- 7 

83- 0 1 
79-9 
55-3 
78. 5 
84. 5 
64- 5 

115. I 
102. 0 
90. 6 
105- 7 

19 

22 

17 
19 1 

1,387 

1, 276 

1, 638 
b 347 

265 

275 

271 

262 

262 

305 


, 222 

301. 2 

91. 8 

21 

I, 304 

1, 422 

Mean : . . . . 






- . 1 _ . 

* 273±4 








Milo, S. P. I, 24960 
{Andropogon sor- 

ghum), June 9 to 
Sept. 27 

' 223 
224 
, 225 

226 

227 

1 228 

475-4 
440. 4 
472. 5 
488. 9 
499-9 

509.9 

60. 0 
85- 7 
77 - 9 
114 0 

1 16, 0 
79. 6 

125. 6 
103. 7 
314- 5 
123- 3 

123. 0 
128. 8 

13 

19 

! 17 

23 
23 

16 

2, 092 

I, 210 

I, 470 

I, 081 

I, 060 

I, 618 

264 

23s 

242 

252 

246 

253 


Mean 







249 ±3 







I, 422 ± 1 15 

Durra, White, S. P, I. 
24997 {Andropogon 
sorghum), June 9 to 
Sept. 26. , . , 

■ 23s 

236 

237 

238 

239 

240 

506.9 
568. 9 
432. 9 
384- 6 

406. 2 

449- 6 

138.7 

142. 7 
85. 6 

63- 5 
78. I 

129. 3 
142. I 
106. 7 
105. I 

99 - 4 
“ 5-9 

27 

25 

20 

17 

^9 

24 

925 

996 

I, 246 

I, 656 

255 

250 

247 

273 


108. 6 

I, 273 

I, 067 

245 

___258 

Mean 






r - T CtA ^ 

255 ±3 







if Ly 4 at 75 

Kaoliang, Brown, S. P. 
24993 {Andropo- 
gon sorghum), June 

9 to Sept. 26 

• 241 

242 

243 

244 

24s 

, 246 

588. 9 
411. I 

548.9 

556.0 
526. 0 
571-8 

144 - 8 
108. 8 
125- 3 
126. 0 
171. 0 
loS. 7 

134. 0 
94 - 8 
120. 5 
123. 8 

1 16. 8 
123. 9 

25 

26 

23 

23 

33 

19 

925 

870 

962 

982 

683 

1, 140 

228 

230 

220 

223 


222 

217 

Mean 






ri 3 " 3 A 









223 ± 1 



22 


Journal of Agricultural Research 


Vol. m, No> X 


Tabi^B XIV . — Water requirement of different sorghums at Akron, Colo., in igi2 and 
igij — Continued 


Plant and period of growth. 


1912. 

Kafir, Blacktull, 

s. p. I. 24975 

dropogon sorghum), 1 
June 9 to Sept. 27, ... 


Mean 

Sudan grass, S. P. I. 
25017 (Andropogon 
sorghum aethiopicus) , 
first crop. May 28 to 
July 26 

Mean 


Sudan grass, S. P. I. 
25017, second crop, 
July 26 to Sept. 6 


Mean. 


Sudan grass, S. P. I. 
25017, combined 
crop, May 28 to 
Sept. 6 


Mean 

1913* 

Sorghum, Minnesota 
Amber, A. D. I. | 
341-13 {Andropogon 
sorghum), June 14 to i 
Sept. 15 

Mean | , 


Sorghum, Red Amber, ! 
S. P. I. 17543 (All- I 
dropogon sorghum), 
June 7 to Sept. 15. . 


Mean 


Pot 

No. 

Dry 

Grain. 

Water. 

Grain. 

Water requirement 
based on — 





Grain. 

Dry matter. 

f ^^9 
230 

1 231 

; 232 
' 233 

. 234 

Grams . 
247. 0 
409. I 
494 - S 

413- 0 
363- 3 
377 - I 

Crams . 

Kilos . 
72. I 
108. 4 

119 - 3 

Ptr cent . 


292 

265 

241 

246 

253 

258 











91.9 

97-4 















259±5 







' 211 

190. 6 
209. 4 
181. 8 


60. 8 



319 

314 

326 

308 

296 

308 


65. 8 

59 - 4 
63. 4 
63.8 
68.6 



213 

214 

215 

216 




205. 8 

215-9 

222. 6 




















3 i 2±3 







211 

212 

213 

214 

215 

216 

106. 7 

94- 0 

95 - 6 
106. 5 
91. 0 
88. 0 


46. I 

43 - 5 

44 - 6 

45 - 9 
42. 9 
43 - 0 



432 

463 

467 

431 

472 

489 




1 






















459±7 







2 1 1 

297- 3 
303- 4 

277-4 

312.3 

306.9 
310. 6 


106. 9 



1 359 

i 360 

375 

350 

348 

360 

212 


109. 3 
104, 0 
109. 3 
106. 7 



213 

214 

215 

2l(j 











II I. 6 












359±2 







265 

266 

267 

268 

269 

270 

557-8 
585.0 
591.8 
677- 5 
577 - 9 
643. 0 

213. 0 
256. 9 
335 - 4 
263. 0 
204. 0 
150. 7 

164. 5 
iSi. 4 
^ 77 - 4 
203. I 

167. s 

189. 7 

38 

44 

40 

39 
35 

23 

772 

706 

754 

773 

821 

29s 

310 

299 

301 

290 

295 








>- 5 -x 

298 ± 2 






/ .■) — 

277 

278 

279 

280 

281 

282 

689. 7 
670. 7 
636, 2 
644. I 
682. 3 
749 - 7 

209. 4 
190. 6 
160. 2 
165. 6 
187. 4 
187.8 

200. 5 
196. 0 
187. 9 

^ 93 - 9 
200. 5 
225. 2 

30 

28 

25 

26 

23 

25 

958 

I, 028 

I, 172 

1, 170 

1, 070 

I, 199 

291 

292 

295 

301 

294 

301 






, 

nr \ f \ ^ T 


i 1 1 


1,100 31 




Oct. 15 . I9«4 


Water Requirement of Plants 


23 


The least efficient variety tested in the sorghum group is Sudan grass 
(PI. V, fig. i), a forage plant which has recently received consider- 
able attention in the southern Great Plains. Only one year's meas- 
urements are available for Sudan grass, but the results so far indicate 
that it is not the equal of other well-known varieties of sorghum in 
efficiency in the use of water. Sudan grass required 40 per cent more 
water than Brown kaoliang for the production of the first crop. 
The second crop was light at Akron and had a much higher water require- 
ment. On the basis of the two cuttings combined, the water require- 
ment of Sudan grass was 62 per cent higher than Brown kaoliang. As a 
forage crop, however, the shorter and more slender stalks of Sudan grass 
may offset the disadvantage of its higher water requirement. 

In the production of grain the Minnesota Amber ^ variety gave the 
lowest water requirement ratio so far recorded for a sorghum cfop, viz, 
6 o7±i 5. The Minnesota Amber produced a pound of grain at Akron 
in 1912 with less water than was required by alfalfa in the production of 
a pound of hay. The high water requirement for grain production in 
Red Amber sorghum, Dwarf milo, milo, and White durra (PI. IV, 
fig. 3) is largely due to an attack of aphids, which caused many of the 
flowers to fail to produce seed. The parasites were killed by spraying 
early enough to prevent any serious reduction in total growth. 

The 1913 water requirement measurements of sorghum were confined 
to two varieties, Red Amber and Minnesota Amber, both of which were 
included in the 1912 measurements. The two varieties gave in 1913 
practically identical water- requirement ratios — namely, 296 ± i and 
298±2. The results from individual pots were in excellent agreement 
as indicated by the small probable error. A similar agreement was 
observed in 1912, Each variety in 1913 showed an increase of 25 per 
cent in the water requirement as compared with 1912. 

A series of water- requirement measurements were made at Amarillo, 
Tex., in 1913, for the purpose of determining the influence of climatic 
environment on the water requirement. These measurements also 
included a number of sorghum varieties, the water requirement of which 
had never before been determined. Plants have a higher water require- 
ment at Amarillo than at Akron, so that measurements of different 
plants at the two stations are not directly comparable. The water 
requirement of Red Amber and Minnesota Amber sorghum was meas- 
ured at both stations in 1913, and the ratio of these measurements affords 
a means for reducing the Amarillo values to the basis of the Akron meas- 
urements. The mean water requirement of these two varieties at Akron 
was 85 per cent of that at Amarillo. The Amarillo water-requirement 
measurements as given in Table XVI have been reduced accordingly 

' This variety was represented by a strain solrctcd for its drouiiht resistance by Mr. A. C. Dillman, of the 
Office of Alkali and Drought Resistant Plant Invcstigatioas. 



24 


Journal of Agricultural Research 


Vol. HI. No. I 


for comparison with the Akron measurements. The computed values 
for Akron are given in Table XV. 


TablS XV. — Observed 'water requirement of varieties of sorghum at Amarillo, Tex., and 
computed water requirement for Akron, Colo., in igi^ 


Variety, 

Observed 

water 

requirement 
at Amarillo. 

Computed 

water 

requirement 
lor Akron. 

j 

Dwarf Blackhull kafir 

White kafir 

Early Blackhull kafir 

White milo 

KafirXdurra 

Feterita 

349 ±4 
3 S 6 ±i 5 
373*3 

378*5 

380*4 

285*3 

297*4 

302*13 

317*3 

321*5 

323*4 



It will be noted (Table XV) that Dwarf Black hull kafir and Minnesota 
Amber sorghum were the most efficient in the use of water of the eight 
varieties of sorghum tested at Amarillo in 1913. The least efficient was 
feterita. The kafir Xdurra hybrid had practically the same water 
requirement as feterita. The latter has been extensively featured 
recently as a drought- resistant crop particularly adapted to the South- 
west. It does not appear, however, that its drought- resistant qualities 
are ascribable to an efficiency in the use of water, this variety being the 
highest in water requirement of all the sorghums tested at Amarillo in 
1913. Vinall and Ball (1913, p. 27) have suggested that the success of 
feterita during recent dry years has been due to a thin stand resulting 
in part from poor germination. When grown under identical conditions 
as to stand, it showed no greater drought resistance than milo or kafir. 

Table XVI. — Water requirement of sorghum at Amarillo, Tex., in IQIJ 








Water requirement 


Pot 

Dry 




' based c 

n — 

Plant and period of growth. 

Grain, 

W^ater. 

Grain. 








Grain. 

Dry matter. 

1913- 


Grants. 

Grams. 

Kilos. 

Per ce.nl. 





717-4 

159-3 

267. 8 

22 

I, 680 

373 

Sorghum, Bed Amber, 

44 

682. 2 

137-9 

262. 4 

20 

1,904 

385 

S. P. I, 17543 (An- 

, 45 

723.6 

205-9 

268. 0 

28 

1,302 

, 371 

dropogon sorghum), 

46 

701, 9 

117. 4 

i 256. 2 

17 

i 2, 182 

365 

May 15 to Aug. 20. . . ' 

47 

741-3 

197-0 

270. 7 

27 

1.374 

365 


48 

768. 7 

208, 7 

272.9 

27 

1,306 

355 

Mean ( 






I, 625*112 

369*3 

1 






Sorghum, Minnesota 
Amber, A. D. 1. 341- | 
13 (Andropogon sor- : 
ghum), May 15 to i 
Aug. 8 ' 

[ 49 

1 

590. 2 

588.3 
612. 7 
646. 0 
577-1 

233-2 ' 
295-4 

291.9 

308.9 
264. 5 

196. 2 
196. 6 
199. 7 
208. 1 
201, 0 

39 I 

50 ! 
48 i 
48 

46 

841 

666 

685 

674 

760 

332 

334 

326 

322 

348 

|l 54 

649- 5 

288. 9 

211. I 

44 

731 

325 

Mean 






726*19 

331*3 

i 








Water Requirement of Plants 


25 


Tabi^B XVI . — Water requirement of sorghum at Amarillo, Tex., in Jp/j— Continued 


Plant and period of growth. 


1913- 

Milo, White, C. I. 365 
{Andropogon sor- 
ghum), June 7 to 
Aug. 22 


Kafir, Early Black- 
hull, C. I. 472 {An- 
dropogon sorghum), 
June II to Sept. 16. 


Mean. 


Kafir, Dwarf Black- 
hull, C. I. 340 {An- 
dropogon sorghum), 
June n to Sept, 16, 


Kafir, White, C. I. 370 
{A ndro pogon $ or - 
ghum), June ii to 
Sept. 22 


Mean . 


Kafir Xdurra, hybrid 
198-15-3 {Andropo- 
gon sorghum) June ii 
to Sept, 22 


Mean. 


Feterita, C. I. 182 (An- 
dropogon sorghum) 
June ir to Sept. 18. . 


Mean. 


Pot 

No. 


Dry 

matter. 


Grams. 

464. 5 
481. 1 
453 - o 
470.0 
449-3 
471. I 


Crams. 
So. 4 
107.3 
75-6 
108. 4 
79.6 

II2. 2 


587-4 

577-8 

599-4 

530-6 

440. 2 
603. 4 


592- 5 
621. 6 
562. 7 

586.7 

544*8 

559-3 


555-3 
546. 2 
571-8 

584. 2 
569. 6 
579 - 6 


552. o 
.538. 4 
539 - 7 

515- o 

51^0. 7 
471- 5 


547-8 
585- 4 
619.3 

S31- I 

562. 8 
512. o 


Kilos. 

173- 5 

166. 3 
171. 9 
176.4 
170.9 
179. 6 


182. 7 
178.6 
235- 7 
193-4 

220. 2 
199.8 


254. o 
276. 1 
205. 2 
260. o 
195.6 
152- 7 


185.9 
ro6. 4 
210. 8 
248. 7 
221, o 
228. 3 


226. 5 
215- 3 
217. 6 
206. 6 

179- 5 

158. I 


181. 3 

235-8 
256.9 
210. 9 
210. 2 

^91-3 


19S. 6 
207.3 
197.6 
169. 8 
206. 9 
192. 1 


I go. 8 
200. o 
19T. 5 
197.9 
191. 7 
187, o 


201. 7 
200. I 
198. 5 
198. o 
194 - 3 
W 5 - 9 


200. r 
W 3 - I 
igg. r 

194. 7 

197. I 
194. o 


212. I 

216. O 
226. 9 

206 . I 

208. 5 
203. 8 


rain« 

Water requirement 
based on — 


Grain. 

Dry matter. 

cent- 



17 

2 , 159 

374 

22 

b 550 

346 

17 

2, 272 

380 

23 

I, 626 

375 

18 

2, 148 

380 

24 

I, 6or 

381 


1 , 893^113 

373 ±3 

31 

I, 087 

338 

31 

1, 160 

■ 359 

39 

839 

330 

36 

878 

320 

50 

940 

470 

33 

962 

319 


978 ±3 7 

356^15 

43 

752 

322 

44 

724 

322 

36 

934 

340 

44 

761 

337 

36 

980 

352 

27 

1,223 

334 


896 ±57 

33 S ±3 

33 

I, 086 
« I, 882 

363 

19 

I 366 

37 

942 

' 347 

43 

796 

339 

39 

879 

341 

39 

858 

338 


gT 2±34 

349 ±4 

41 

884 

363 

40 

898 

358 

40 

916 

369 

40 

942 

378 

35 

1, ogS 

386 

23 

I, 226 

411 


994±42 

378±5 

33 

r, 170 

387 

40 

916 

369 

41 

884 

366 

41 

• 979 

388 

37 

992 

370 

37 

I, 064 

398 


I, OOI ±29 

380 ±4 


Omitted in computing the mean. 



26 


Journal of Agricultural Research 


Vol. Ill, No. I 


AND PROSO 

Those plants are remarkable in that they outrank all others so far 
tested as regards efficiency in the use of water (Table XVII). The four 
varieties grown at Akron in 1912 gave the following water requirement, 
based on the production of dry matter: 


Variety of millet or proso Water requirement 

Kursk millet i87±2 

Voronezh proso 2o6ii 

Tambov proso 208 ± i 

German millet 248±7 


Kursk millet (PI. V, fig. 3) represented by a strain developed by 
Mr, A. C. Dillman, of the Office of Alkali and Drought Resistant Plant 
Investigations, gave the lowest water requirement so far recorded for 
any crop at Akron. The two prosos, Tambov and Voronezh (PI. V, 
fig. 2), have a water requirement about 10 per cent higher than the 
Kursk, while German millet is 33 per cent higher than the Kursk. Aside 
from the German millet, all of the varieties tested have a water require- 
ment distinctly below the best of the sorghums, the group ranking next 
in efficiency. 

TabItS XVII . — Water requirement of different millets and prosos at Akron, Cole,, in 
igi2 and iqij 


plant and period of growth. 

Pot 

No. 

nry 

matter. 

Grain 

V'aUT. 

Grain. 

Water requirement 
based on — 

Grain. 

Dry matter. 

igi2. 


Crams. 

Grams. 

K ilos . 

Per cent. 




■ 205 

I go. 7 

66. I 

3C 7 

35 

555 

192 

Millet, Kursk, S. P. 1 . 

206 

320. 0 

I IQ. I 

58. 9 

37 

494 

184 

34771 (Chaetockloa 

207 

241. 7 

102. 6 

44. I 

42 

430 

182 

italica), June g to 

208 

192. 5 

78.4 

36. T 

41 

461 

188 

Aug. 20 

209 

178.9 

66. 5 

32.6 

37 

490 

182 


. 210 

332 - 6 

139-3 

65. 0 

42 

467 

195 







483 ± 1 1 

i87±2 


■ 187 

115. I 


27-3 


237 

Millet, German, S, P. I. 

188 

202. 6 


46. 7 




26845 {Chaetockloa 

189 

140. 0 


33 - 9 



242 

italica), July 2 to 

190 

350 - 3 1 


82.4 



235 

Sept- 23 

igi 

02. ^ 1 


22 , 4 



242 







Mean 

192 

80. 5 

i 

1 34. 2 



301 

248 + 7 


f ig.i 

235‘3 

III. 0 

.34. 8 

43 

494 

214 

Proso, Tambov, S. D. 

194 

342-9 

162, 4 

63 . 0 

47 

419 

igS 

366, Akron, 366-1-10 

f J95 

190. 0 

80. 7 

39 - 7 

42 

492 

209 

{Panicum miliaceum), 

j ^96 

317- 6 

140. 2 

66. s 

44 

474 

209 

June 8 to Aug. 12 

-97 

33 ^- 2 

142. 8 

70. I 

43 

491 

208 


1 19S 

282. 7 

1 12. 6 

58*9 

40 

523 

20S 

Mean 






482^:9 

208 i I 

i 

1 







Oct. 15. * 9^4 


Water Requirement of Plants 


27 


Table XVII . — Water requirement of different millets and prosos at Akron, Colo., in 
1 012 and jpij — Continued 


Plant and period of growth. 

Pot 

No. 

Dry 

matter. 

Grain. 

Water. 

Grain. 

Water requirement 
based on — 

Grain. 1 Dry matter. 

1 

1912. 


Grams. 

Crams. 

Kilos. 

Per cent. 




199 

238- 7 

1 14. 2 

48. g 

48 

428 

205 

Proso, Voronezh, C. I. 

200 

296. I 

143 - 7 

61. 2 

48 

426 

207 

16 {Pameum milia- 

201 

281. 9 

135- ^ 

56. 8 

48 

419 

201 

ceum) , J une 5 to Aug . 

202 

298. 5 

149 - 5 

59 - 9 

50 

401 

201 

20 

203 

256. I 

1 19. 4 

S 3 - 7 

47 

450 

210 


204 

273.0 

133- 2 

57 - 0 

49 

428 

209 

Mean 






425±4 

206 ± I 

1913- 









' 259 

174. 8 

37 - I 

48. 9 

21 

1,318 

280 

Kiu-sk, S- P. I. 34771 

260 

281. 7 

76. I 

80. 7 

27 

I, 060 

286 

{Chaetochloa italica), 

261 

175^4 

71. 6 

so- S 

41 

705 

288 

June 14 to Aug. 26. . 

262 

183-3 

3^-9 

SI - 3 

17 


2 So 


263 

250. 6 

33-4 

66.3 

13 


265 


. 264 

201. 8 

74 - 0 

63- 5 

37 

00 

00 

315 

Mean 


1 





286ib4 


In grain production the millets make a remarkable showing, the 
prosos leading in this respect. Measurements of the water require- 
ment of the three varieties, based on grain production, gave the follow- 
ing results; 

Variety of millet or proso Water requirement 


Vorone zh proso 42 5 ± 4 

Tambov proso 482 ±9 

Kursk millet 483±ii 


Voronezh proso, according to these figures, is able to produce nearly 
2 pounds of grain with the water required for the production of i pound 
of alfalfa hay. 

Kursk millet was also included in the 1913 measurements. Its water 
requirement was 286±4, or 53 per cent higher than in 1912. Many of 
the plants were broken by a high wind shortly before harv^est, which 
greatly reduced the grain yield. The mean water requirement, based on 
grain production, has consequently been omitted. 

LEGUMES 

The legumes tested at Akron in 1912 included sweet clover, chick-pea, 
and two strains of Grimm alfalfa, one being a selected strain (Pl.V, 
figs. 4 and 5) developed by Mr. A. C. Dillman. Both the alfalfa and 
the sweet clover showed a marked reduction in water requirement 
compared with the results obtained in 1911. Three cuttings were made 
in the case of each crop, but the plants were not mature at the time 



28 


Journal of Agricultural Research 


Vol. Ill, No. t 


the last cutting was made. The following values (Table XVIII) were 
obtained for the water- requirement ratio : 


Tabi,^ XVIII. — Summary of water-requirement Tneasuremenis of legumes at Akron t 
Colo., in igi2 


Crop. 1 

1 

Cutting:. 

First. 

S«coticl. 

Third. 

Combined. 

Alfalfa, Grimm 

Alfalfa, Grimm, A. D. I. selection 

Clover, sweet 

Chick-pea 

592 ±13 

6 oo ± i 7 
547 ±12 

79o±io 

853 ±13 

677±I4 

42idbio 

593 ±18 

659 ±6 
657 ±ii 
638 ±4 

5 io±i 4 


i 




The two alfalfas and the sweet clover w*cre planted on the same day, 
and the crops in each instance were all cut on the same day, so that the 
results in the Table XVIII are comparable. The A. D. I. strain of 
Grimm alfalfa gave a slightly higher ratio than the unselected Grimm 
during the second period, but lower during the third period, when it made 
a better growth. (See “Dry matter/' column 3, Table XIX.) Sweet 
clover, as in 1911, proved somewhat more efficient than alfalfa during 
the first and second periods. During the third period sweet clover was 
less efficient than alfalfa. 

The chick-pea proved the most efficient of the legumes tested. Its 
growth period does not coincide with that of the other legumes, but 
approximates a combination of the first and second periods. (See Table 
XIX.) It thus appears to be distinctly more efficient in the use of water 
than either alfalfa or sweet clover. Chick-pea has, however, a relatively 
high water requirement compared with the small grain crops, which is in 
accord with leather’s measurements (Leather, 1910, p. 156). 

Table XTX . — Water requirement of different legumes at Akron, Colo., in igiz 


Plant and period of erowth. 

Pot 

No. 

Dry 

matter. 

Grain. ] W'ater. 

i 

Crain. 

Water requirement 
based on — 

Crain. 

Dry matter. 

1912. 

Alfalfa, Grimm, S. P. 

I. 25695 {Mcdicago 
saliva), first crop, 
May 23 to July 26. . . 

Mean 

■ 127 

128 

129 

130 

131 

132 

Grams. 
no. 3 

1 18. 5 
141. 4 
124. 2 

1 12. 4 

156.8 

Crams. 

Kilos. 
60. 3 
77- 3 

86. I 

74.8 
59- 9 
95- 0 

Per cent. 


548 

652 

609 

602 

533 

606 





















59^±i3 

Alfalfa, Grimm, second 
crop, July 26 to Sept. 

' 127 

128 

129 

130 

172 

141. 2 
II2. 5 

129. I 

125. 0 

131. 2 
168. 3 


112. 4 
97. D 
100, 8 
g8. 8 
ICO. I 
125. 8 

i 




796 

862 

781 

790 

763 

748 










t 







■Mean 1 




! 1 

790dbio 




1 

; 

■ ! 


Water Requirement of Plants 


TablS yiiyi— Water requirement of different legumes at Akron, Colo., in igiz—Contd, 


Plant and period of growth. 


No! m2£r. Grain. Water. Grain. 


Water requiretnent 
based on — 


Grain. Dry matter. 


Alfalfa, Grimm, third 
crop, Sept. 6 to Nov. 


Crams. Grams. 
68 . 2 


Alfalfa, Grimm, com- 
bined crop, May 23 
to Nov. 4 


127 319. 7 

128 296. 7 

129 330. 4 

130 301. I 


Alfalfa, Grimm A. D. I. 
K-23-20-52, first 
crop, May 24 to July 
26 


Alfalfa, Grimm, second 
crop, July 26 to 
Sept. 6 


^33 131- 7 

134 no. o 


-I 853^13 


Alfalfa, Grimm, third 
crop, Sept. 6 to Nov. 
4 


Alfalfa, Grimm, com- 
bined crop. May 24 
to Nov. 4 


Clover, sweet, S. P. I. 
2 i 2 i 6 (.^f€lilotus alba), 
first crop, May 23 to 
July 26. 


Mean, 


547 i 12 



30 


Journal of Agricultural Research 


Vol. m, No. t 


Tabl^ XIX . — Water requirement of different legumes at Akron, Colo,, in IQI2 — Contd. 


Plant and period of growth. 

Pot 

No. 

Dry 

matter. 

Gram. 

Water. 

Grain. 

Water requirement 
based on — 

Grain. 

Dry matter. 

1912. 

Clover, sweet, second 
crop, July 26 to Sept. 

{ 121 

122 

^23 

124 

1 125 

Grams, 

155-3 
130- 5 
103. 8 
143-9 
149.0 

Grams. 

Kilos. 
III. 6 

87- S 

i 74 - 7 
94 - 5 

92-3 

Per c€t%t. 


719 

670 

720 

657 

620 


















677 ±14 

Clove r , sweet , third 
crop, Sept. 6 to Nov. 

121 

122 
123 

. 124 

23-9 

19.4 

15-3 
j 14- 8 


12. S 
12. 0 

9 - 3 
9 - 5 




522 

619 

608 

642 















598 ±18 

Clover, sweet, com- 
bined crop, May 23 
to Nov. 7 

f I 2 I 

1 122 

1 123 

1 124 

287.4 
211. 4 

183. 5 

228.3 


185. 5 

136-3 

1 17. 6 
141. 7 




64s 

645 

641 

621 










Mean 





638 ±4 

Chick-pea, S. P. I. 
24322 {Cicer arieti- 
num) , June 3 to Aug. 
30 

157 

158 
, ^59 

160 

161 
ll 162 

239-9 

275- S 
238. 3 

181. r 
272. 0 
227. 0 

97.0 
126. 3 
83. 0 
47 - 2 ' 
120. I 
104- 5 

138.0 
129. 1 
127. I 
96. 0 
129. 4 
108. 6 

40 

46 

36 

26 

44 

46 


b 423 

I, 022 

^495 

2,032 

b 077 

bo 39 

576 

469 

533 

530 

476 

478 


i i 

I, 348 ±ii 4 

5 io±M 


i i I 

i 


A number of different legumes were included in the 1913 water- 
requirement measurements at Akron (Table XX). On the basis of dry 
matter produced, the results obtained are as follows: 


Kind of legume Water requirement 

Cowpea 57^±3 

Soybean 672 ±9 

Navy bean 682 ±4 

Peruvian alfalfa 651^12 

Hairy vetch 690^8 

Horse bean, S. P. I. 25643 772iii 

Mexican bean 773 ±8 

Canada pea 775 ±S 

Horse bean, S, P. I. 15429 78oi;i9 

Red clover 789±9 

Crimson clover 8o5±8 

Wild soy bean 815^25 

Grimm alfalfa 834^8 

Purple vetch 935±9 



Oct. 15 . 19*4 


Water Requirement of Plants 


31 


Cowpea (PI. VI, fig. i) was the most efficient of the cultivated 
legumes. The least efficient was purple vetch. The water requirement 
of the first crop of hairy vetch (PI. VI, fig. 2) was 9 per cent less than 
for purple vetch, the period of growth being the same for both varie- 
ties. Some of the pots of hairy vetch produced a good second growth, 
but none of the pots of purple vetch were able to survive the first cutting. 
The water requirement of the combined crops of hairy vetch was 69o±8, 
or about three-fourths that of purple vetch. Of the soy beans (PI. 
VI, fig. 3) the wild required 21 per cent more water than the cultivated 
variety, which in turn required 18 per cent more water than cowpea 
(See Table XX.) 



Mean, 


8i8± II 



32 


Journal of Agricultural Research 


Vol. m. No. 1 


Tabt^s XX . — Water requirement of legumes at Akro 7 t, Colo., inigzj — Continued 


Plant and period of growth. 


Alfalfa, Grimm, com- 
bined crop, June 5 to 
Oct. 23 


Mean. 


Alfalfa, Peruvian, S. 
P. I. 30203 (iV/erff- 
cago sativa), first 
crop, June 7 to July 

19 


Mean. 


Alfalfa, Peruvian, sec- 
ond crop, July Ip to 
Aug. 26 


Alfalfa, Peruvian, third 
crop, Aug. 26 to Oct. 


Dry 

matter. 


325 - 9 

298. 6 
281. 5 

306. 2 
297. 9 
285. 6 
2 86. 2 
285. r 

307. 6 
250. I 
266. 7 
314.8 


41- 5 
70-3 
66. o 
45 o 

75.8 

87.9 


97 

98 

99 
roo 


Alfalfa, Peruvian, com- 
bined crop, June 7 
to Oct. 33 


Mean. 


Clover, red, S. P. 1. 
34869 {TrifoHum re~ 
pens) , fi rst c rop , June 
5 to July 19 


Mean, 


( 108 


62. o 
104- 5 

91. 4 
69. 9 
88. 4 
102. 3 


63. 6 
99. 2 
85. o 
74- S 
(‘^) 

108. 9 


167. I 
274. o 
242. 4 
189.4 
299. 1 


99- 7 
71. o 
89.6 
92. 6 
1 16. 3 
112. 8 


Water, 1 Grain. 


Kilos. 
288.3 
257. 8 
2^7- S 
243. 2 
259‘ 5 

234-3 

233-0 

231. 8 
262. I 
221. s 
221. C 
251. 9 


26. 3 
45- 5 
38- 9 
27- .3 
54- 8 
64. 4 


42. 5 
7.3-3 
63- 9 
47- o 
69- 5 

82-5 


39-9 
55- 5 
49-9 
42. 6 
58.8 

69-3 


ToS. 7 
04-3 
152- 7 
1 16. 9 
216. 2 


73- 1 
56, o 
60. 3 
63. 6 
82. o 
81. I 


Water requirement 
based oil — 


Grain. Dry matter. 


886 

864 

773 

801 

871 

821 

814 

813 

8.53 

886 

831 

800 
834 ±8 


6.34 

648 

590 

606 

695 

733 

65 i ± i 6 


685 

701 

699 

672 

786 

S06 


72Si:i8 


627 

559 

587 

572 


636 


.j 596dbi2 


651 ± 12 


7iSi 1 1 


Missing, 



Oct. 15, 1914 


Water Requirement of Plants 


33 


Table XX . — Water requirement of legumes at Akron, Colo., in Jgzj — Continued 


plant aod period of growth. 


1913- 

Clover, red, second 
crop, July 19 to 
Aug. 26 


Clover, red, third 
crop, Aug. 26 to 
Oct. 22 


Mean. 


Clover, red, combined 
crop, June 5 to Oct. 


Mean. 


Clover, crimson, S. P. I. 
33742 {Trifolium in- 
carnaium), Tune t; to 
Aug. 26 


Mean . 


Vetch, hairy, S. P. I. 
34298 ( Vida -villosa), 
first crop, May 20 to 
July 18 . . . . 


Mean . 


Vetch, hairy, second 
crop, July 18 to Oct. 


Mean . 


V'ctch, hairy, com- 
bined crop, June 5 
to Oct. 22 


Mean 

60300°— 14- 


Pot 

No. 


103 

104 

105 

106 

107 

108 


103 

104 

105 
206 

107 

108 


103 

104 

105 

106 

107 

108 


T09 

iro 

111 

112 

113 

ri4 


r8i 

1S2 

183 

184 

185 

186 


181 

184 

185 

186 


iSi 

184 

185 

186 


Grams. 
62. 7 

66. O 

39- 5 
62. 8 
52- 5 
46. 6 


13. 6 
18.3 
9- 7 
8-5 
37- 7 

10. 4 


176. o 
155' 3 
138.8 
163. 9 
206. 5 
169, 8 


191- 3 
169. 2 
186. 2 
146. 7 
109. 8 
iro. 2 


119, 4 i 
97-8 ; 
9A I 
1 14. 5 : 
121. 9 i 
120. 2 ^ 


1 14. 8 L 
148.4 
155- 7 ; 

131-7 


234. 2 
262. 9 
277.6 
251- 9 


Kilos. 
53-9 
53- o 
36. o 
53-9 
45- 7 
44*4 


17.0 
17-4 
10. 7 
9. o 
26. o 
12. 9 


144- o 

126. 4 
107. o 
126. 5 

153-7 

138. 4 


260, 8 
131. o 

150. 5 

1 18. I 
84. 9 
91. o 


93- 3 
76. 9 

95- 9 

99. 6 
98. 9 
106. 9 


61. 7 
So. I 
92. 6 
74- 7 


155-0 
179. 7 
191- 5 

181, 6 


Water requirement 
based on— 


Grain. Dry matter. 


860 

803 

911 

858 

870 

953 

876 ±i 4 


I, 250 

‘ 952 

1, 103 
I, 05S 
6S9 
I, 040 


1iOI5±49 


818 

814 

771 

772 

745 

815 


7894=9 


841 

774 

809 

S06 

773 

83c 


805 i 8 


786 

977 

870 

811 

890 


^^53 4:23 


537 

540 

595 

567 

560 ±10 


662 

684 

690 

722 

6 go±8 



4 Journal of Agricultural Research voi. m. no. 

Tabi.s XX . — Water requirement of Ugumes at Akron^ Colo., in ipij — Continued 


Plant and period of growth. m^ter Grain, Water. Grain. 


Grain. Dry matter. 


Vetch, purple, S. P. I. 
1813 1 ( Vida airo pur- 
purea), May 29 to 
July 18 


Grams. Grams. Kilos. Per cent. 

\ “7- 5 ^*3- 7 

iiS. 5 108.8 

128. 9 1 19. 8 

113.8 106.0 

102.4 99.6 

1 1 5. 2 102. 3 


Pea, Canada field, 
S. P. I. 30134 (Pj- 
sum sativum), June 
3 to Aug. 4 


244 134 . 2 

245 12a o 


64.7 1 17. 9 

50. 3 104. 5 

46. 6 103. 8 

51,4 103.0 


Bean, Mexican (Phase- 
olus vulgaris), May 
28 to Sept. I 


■ 229 282.4 120- S 213.9 

230 269.0 117,0 205.1 

231 260.7 108. g igi. o 

232 232.8 100.7 182.8 

233 276. 2 III. 9 218. 4 

i 234 245.3 7 198.0 


Bean, navy {Phaseolus 
vulgaris), May 28 to 


223 220. 3 

224 204. o 


Bean, soy, S. P. I. 
2I7S5 {Glydnc his- 
pida), June I to 
Aug. 26 


Bean, soy, wild, 
S. P. I. 25138 {Gly- 
cine soja), June 12 to 
Sept. 14 


228 

186. I 

193 

156. 2 

194 

144. 7 

19s 

150. 4 

196 

158. 2 

197 

154- I 

198 

160. 0 

199 

255-9 

200 

305-0 

201 

346. I 

202 

303-0 

203 

374-9 

204 

329- 7 


Mean, 


81 Si*.'; 



Oct. 15. 19*4 


Water Requirement of Plants 


35 


Tabj.^ yi^. —Water requirement of legumes at Akron, Colo., in Continued 


plant and period oi jjrowth, 


Cowpea, S. P. I. 29282 
(Vigna sinensis), 
June 17 to Aug. 26. . 


Bean, horse, S. P. I. 
15429 (V^teta faba), 
June T2 to July 19. . 


Mean. 


Bean, horse, S. P. I. 
25645 {Victa faba), 
June 17 to July 9. . . 


151 

152 

153 

154 

155 

156 


169 

170 

171 

172 

173 

174 


175 

176 

177 

178 

179 

180 


Crams, 
207. o 
202 . 6 
2IS- 7 

209. 2 

210. 6 
202. 7 


38.3 

53- 7 
44. 6 
30.0 
10. o 

17.4 


9.4 
40. 9 

29.4 
S.V6 

^ 8-5 

10. 4 


Cramj. 

69. 9 
71.4 
80. I 
77- 7 
75- o 
79-5 


Kilos. 
123. I 

1 15. 6 
121. 7 
ri6. 1 

120. o 

1 16. I 


31.0 

38.4 

33-4 
21.7 
8. 7 
14. I 


34- o 
21.8 
41 - 3 

’3- 5 
8-3 


Per cent. 

34 

35 
37 
37 

36 
39 


ij 761 
r, 620 

^519 

Ij 49 S 
1, 600 
I, 460 


i, 576±32 


595 

57 ^ 

564 

555 

570 

573 

57 ii 3 


. 809 

715 

749 

723 

870 

811 


780 it 19 


755 

831 

742 

774 

730 

798 


772 ill 


Neither variety of horse bean did well. The growth was fairly good 
during the early period, but during the warm days of Jidy the plants 
wilted down badly, despite an ample water supply, and had to be 
harvested before they had reached maturity. The water rt^quirenient, 
notwithstanding this, is no higher than that of many of the other 
legumes, and compares favorably in this respect with hairy and with 
purple vetch. The navy bean, although not as efficient as the cowpea and 
the soy bean, is more efficient than the Mexican bean, which required 13 
per cent more w^ater. The Canada field pea and the Mexican bean were 
equally efficient.* 

Crimson clover, on the basis of the combined crop, required practically 
the same quantity of water as red clover. Crimson clover produced only 
one crop and grew slowly throughout the period, although in total pro- 
duction it was practically the equal of red clover. The water require- 
ment of red clover is slightly below that of Grimm alfalfa, while Peruvian 
alfalfa required only 78 per cent as much water as Grimm for the pro- 

• Peas and beans were included by Lawes (1850, p. 54) in his experiments at Rothamstcad. Hntrland. 

IS racasuranents show beans to be slightly more eflident than peas. No other measurements of peas 
and beans have been made, so far as the writers are aware. 



36 


Journal of Agricultural Research 


Vol. Ill, No. I 


duction of a pound of dry matter. The total dry matter produced by 
Peruvian was, however, much less. The water requirement for each of 
the several cuttings made of these crops is shown in Table XXI. 


Tabi,t^ XXI. — Water requirement of different cuttings of legumes 


! 

Crop. ' 

First 

cutting. 

Second 

cutting. 

i 

! Third 

1 cutting. 

Combined 

cutting. 

Alfalfa, Peruvian ' 

Clover, red 

Alfalfa, Grimrri 

Vetch, hairy 

651^16 
7i8±ii : 
804 ±9 

^53 ±23 

725±i8 

876±14 

1 878±8 
560^10 

5g6±i2 

i,oi5±49 

8i8±ii 

65i±I2 
789^9 
834±» 
690 ±8 




Taking the water requirement of the first cutting in each instance as 
a basis of comparison, the second crop of Grimm alfalfa required 8 per 
cent more water, Peruvian alfalfa ii per cent more, red clover 22 per 
cent more, while hairy vetch required 34 per cent less. On the same 
basis the third cutting of Grimm alfalfa required 2 per cent more water 
than the first, 8 per cent more for Peruvian, and red clover 41 per cent 
more. Comparing the combined cuttings, Peruvian alfalfa and hairy 
vetch required 18 per cent less water than Grimm, and red clover 5 per 
cent less. Grimm alfalfa was the only one of the lupines grown at Akron 
during both 1912 and 1913. Its water requirement in 1912 was 659^16; 
in 1913, S34±8, an increase of 27 per cent. 

AUFAUFA, SUDAN GUASS, AND MIDGET GROWN DURING THE DATE 
SUMMER AND AUTUMN AT AKRON, COLO., IN 1912 

In Table XXII are given the results of water- requirement measure- 
ments based on the total dry matter produced by crops grown during 
the late summer and autumn and planted in pots which had already 
produced a crop earlier in the season. The soil was not changed, 
and no additional fertilizer was added. These forage crops can not be 
said to have been grown out of season, except in that the plantings were 
made too late in the season to permit the plants to reach their full 
development before har^^esting. 


Table XXII. — Water requirement of alfalfa, Sudan grass, and millet grown during the 
late summer and autumn at Akron, Colo., in I912, without additional fertilizer. 


Crop. 

Pot 

No. 

Dri' matter. 

Water, 

Water re- 
quirement 
based on 
dry matter. 

1912. 1 

. . i 

Alfalfa, Grimm, H-2j -20-52 (Medicago saliva), j 
Aug. 7 to Nov. 6, following Kharkov wheat ... . 

Mean 

r 37 

1 39 
< 40 
41 

1 42 

Gram.t. 
40. 9 
43- I 

33- 2 
32. 0 

34- 3 

Kilos. 
40. 4 
37-3 
31-7 
30. 2 
34-9 

988 

866 

955 
i 944 

! 054il6 

1 







Oct. 15. I 9«4 


Water Requirement of Plants 


37 


TablC XXII . — Water requirement of alfalfa, Sudan grass, and millet grown during 
ike late summer and autumn at Akron, Colo., in 1912, without additional fertilizer — 
Continued 


Alfalfa, Grimm, following Turkey wheat. 


Mean. 


Alfalfa, Grimm, Sept. 3 to Nov. 7, following 
Bluestem wheat 


Alfalfa, Grimm, following unfertilized Kubanka 
wheat 


Mean. 


Alfalfa, Grimm, Sept, g to Nov. 4, following 
Grindelia squarrosa 


Mean . 


163 

164 


Alfalfa, yellow flowered {Medicago falcate), Sept. 
3 to Nov. 7, following Kubanka wheat 


Sudan grass, S. P. I. 25017 {Andropogon sorghum 
aeihiopicus), Sept. 3 to Oct. i, following spring 
Ghirka w'heat 


Mean. 


Proso, Black Voronezh, S. D. 331 {Panicum 
miliaceum), Aug. 22 to vSept. 28, following 
Beldi barley 


Mean. 


97 

g 8 

99 

101 

102 


Grams. 

40.4 
45-3 
21. 0 
25. 6 
30 - 7 
33-0 


14. 7 
16. S 

18. r 

19. 6 
13.8 
12. 9 


14. 7 
19. 8 
15 - o 

16. 4 
16. 7 


12. 9 
11.8 


10. o 
10. 8 
16.5 


18. ] 


20. o 
25.0 
19 * S 
15-5 
2a o 


Kilos. 

34-8 

40. 5 
21.3 

23.0 
26. 9 
30 - 7 


7-5 

8.5 

S -3 

8. I 
6 . I 

6.6 


9 - 3 

TO. 8 
9. 1 
9 - 5 
9 - S 


7 - 5 

6. 4 


4. 6 
5 - I 
8 ' 3 


3-0 
5-4 
3 - I 
5.8 
5 - 7 
3 * 4 


Water re- 
quirement 
based on 
dry matter. 


862 

894 

899 

876 

930 

9I2±IS 


510 

506 

458 

413 

442 


473 ±13 


628 

54 .? 

606 

579 

569 




581 

542 


564± i 6 

460 

472 

503 


478±Jo 


4 - 4 

5.8 

3 - 7 
4. o 
4.6 


261 

29S 

295 

297 

343 

354 

30S ± 10 


220 

232 

190 

258 

230 


226±7 1 



38 


Journal of Agriculiural Research 


Vol. m, No. 1 


Tabi^E XXII . — Water requirement of alfalfa, Sudan grass, and millet grown during 
the late summer and autumn at Akron, Colo., in igi2, 'without additional fertilizer — 
Continued 


Pot 

No. 

Do’ matter 

Water. 


Crams. 

Kilos, 

■ 103 

27. 0 

7-8 

J 04 

28. 3 

8-5 

, 105 

30-7 

8.4 

106 

30-4 

8. 9 

1 107 

33 ' 5 

9.2 

1 ro8 

35 ‘ I 

11.7 

f IIS 

9-3 

1.8 

116 

12.4 

i 5 

117 

19 - 3 

4- 0 

118 

24, 2 

3-9 

iig 

23-5 

3-1 

120 

12.3 

1. 8 

61 

22. 2 

3 - 7 

62 

18. 4 

2.9 

63 

23-4 

3-7 

64 

21. 6 

3-8 

6S 

24. 7 

3 - 7 

66 

24 > 5 

3-8 

j_ 

i 1 


Water re- 
quirement 
based on 
dry matter. 


Millet, Turkestan, S. P. I. 206^4 {Ckaetochloa 
italica), Aug. 22 to Oct. i , following Whit 
less barley 


Mean . 


Millet, Kursk, S. P. I. 30029 (Chietochlon italica), 
Sept, 3 to Oct. 3, following spring r>"e 


Mean . 


Millet, Kursk, S, P. I. 34771, Sept. 3 to Oct. i, 
following emmer 


389 

300 

273 
293 

274 
333 

2g4±6 


194 

202 

207 

132 

146 


173^10 

167 

158 

175 

150 

155 


i6i±3 


The effect of fertilizer added to the previous crop on the water require- 
ment of the next crop is shown in the following measurements: 


Water 

erop requirement 

Alfalfa, following fertilized Bluestem wheat 473 ±13 

Alfalfa, following unfertilized Kubanka wheat 535±ii 

Alfalfa, following fertilized Grindelia, following unfertilized 
Bluestem wheat 564^16 


The water requirement of alfalfa following unfertilized Kubanka wheat 
was higher than that following the fertilized Bluestem, and although 
this difference is not very marked (i9±3 per cent) when the probable 
error is considered, it is sufficient to show a slight effect of two consecu- 
tive crops without fertilizer in increasing the water requirement. Two 
pots of alfalfa following Grindelia squarrosa had a water requirement 
equal to that of the unfertilized set. Grindelia was started in pots which 
had already produced a crop of Marvel Bluestem wheat in 1911 without 
fertilizer, therefore alfalfa was the third crop from the same soil mass, 
and although the pots growing Grindelia were fertilized, the succeeding 
alfalfa crop gave a water requirement in accord with that following 
unfertilized wheat. 



Oct. xs. 19x4 


Water Requirement of Plants 


39 


The effect of time of planting is shown in the following determinations 
of the water requirement of alfalfa : 

Water 

requirement 

Alfalfa, grown August 7 to November 6, following Kharkov 

wlieat 954 iiO 

Alfalfa, grown August 7 to November 6, following Turkey wheat. 912 £15 
Alfalfa, grown September 3 to November 7, following Blue stem 

473 ±13 

Alfalfa planted during the dry, hot days of August required almost 
twice as much water for the production of a unit of dry matter as it did 
when planted in September. 

The seven varieties and strains given in Table XXIII were included in 
these late-season experiments and were grown under comparable x:ondi- 
tions. The water requirement of Grimm alfalfa, Sudan grass, and Kursk 
millet was also determined in midsummer (see column 3), so that it is pos- 
sible to reduce the water- requirement measurement of the other late-season 
crops to a midsummer basis. The seasonal water requirement of Grimm 
alfalfa was 39 per cent higher than that of the late-season crop. Assum- 
ing this ratio to hold for the yellow-flowered alfalfa, the seasonal water 
requirement of the latter would be 865 £18. The midsummer water 
requirement of Sudan grass and of Kursk millet (S. P. I. 34771) was in 
each instance 16 per cent above the late-season crop, and this ratio has 
been used in computing the other millets to a midsummer basis. The 
computed values (a) arc given in the last column of Table XXIII. 


Tabi.iJ XXIII . — Water requirement of late-season crops 


Variety. 

Water requirement. 

I^atc-scason 

crop. 

1 Midsummer 
crop. 

Alfalfa, yellow-flowered 

Alfalfa, Grimm 

Sudan grass. 

i 1 

478iio 

473±i3 

3o8±io 

294±6 

226±7 

i6i±3 

a 865 ±i8 
6s7±ii 
359±2 
'*34i±7 
^ 262 ±8 

“ 20I±I2 

IS7 ±2 

Millet, Turkestan 

Proso, Black Voronezh 

Millet, Kursk, S. P. I. 30029 

Millet, Kursk, S. P. I. 34771 


Computed. 


Of these seven varieties the j'cllovv-flowered alfalfa {Medkago jalcaia) 
gave a water requirement in practical accord with tlie Grimm selection 
grown during the same period. Kursk millet (S. P. I. 34771) gave the 
lowest water requirement and proved to be decidedly more efficient than 
Black Voronezh proso and Turkestan millet. Sudan grass required 91 
percent more water than the Kursk millet, which is in exact accord with 
the results obtained for these two crops from determinations based on a 
whole season’s growth. 




40 


Journal of Agricultural Research 


VoL HI, No. I 


CUCURBITS 

On account of the large space required by crops which produce vines, 
the cucurbits were grown outside the inclosure at Akron in 1913* The 
reduction in water requirement produced by the inclosure amounted in 
the case of wheat, alfalfa, and cocklebur to approximately 20 per cent. 
These ratios for the cucurbits should therefore be reduced by this amount 
in comparing them with crops grown inside the shelter. The observed 
water requirement outside and the computed water requirement within 
the inclosure, both based on dry matter, follow: 


Qfpp Outside Inside 

Watermelon 750^19 6oo±is 

Cantaloupe 778 ±34 621^27 

Cucumber 891 ±14 7^3i 

Squash 936±io 748±8 

Pumpkin i,043±2i 834±i7 


The cucumber, cantaloupe (PI. VI, fig. 4 )> and watermelon did well in 
the pots. Squash and pumpkin produced very little fruit (Table XXIV), 
and the growth of vines was not normal. Watermelon and muskmelon 
proved to be the most efficient of the cucurbits. Pumpkin, the highest 
of the cucurbits in water requirement, is about the equal of alfalfa in 
efficiency. 

Table XXIV . — Water requiranent of cucurbits at Akron, Colo., in /p/j 


Plant and period of growth. 

Po» ! Dry- 
Xo. 1 matter. 

Dry 

rnaller 

in 

fruit. 

Water. 

Water requirement 
based on — 

Pruft, 

Fruit |l>ry matter. 

^913- 

Squash, Hubbard (Cm- 
curbita maxima), 
June 3 to Sept, 13 . . 

Mean 

Grams. 

337 272. 0 

338 280. 9 

339 244 - 3 

340 247, 3 

341 267, 9 

342 258.9 

Grams. 
46. I 

85. 6 

33 - 4 
18. 4 
68. 6 

7 < 3 

Kilos. 
260. 7 
252. I 
224. 2 
242. 9 
244- 9 
244- 7 

Pfr cett t. 

17 5 > 658 

30 2,945 

U 6,715 

7 

26 3,570 

3 

4, 720-1:690 

959 

8g8 

918 

982 

gi 4 

946 

936±io 

Pumpkin, common [ 
field (Cucurbita j 
pepo), June 3 to 
Sept. 13 

343 205. 9 

344 222. 4 

345 228.8 

346 225.4 

347 190- 5 

348 179. 7 

.S -9 
45 ' 9 

2. 8 

215. 6 
221. 0 
211. 6 
243. 2 
21 ^ 2 

3 

20 

* I 

1,047 

994 

925 

1,078 

1, 130 

Mean 

2.8 

194. 6 

2 

1,083 

r, 043 ± 2 i 


319 171. I 

loi. 5 ! 

154. 8 

59 U525 

905 

Cucumber, Boston j 

320 185. 6 

100. 0 

167, 6 

54 1.676 

903 

pickling {Cucumis \ 

, 321 185.7 

96- 3 

158. 2 

42 1 , 643 

852 

sativus), June 14 to 

322 182. 5 

112. 4 

1 52' 9 

62 1,3^ 

838 

Sept. I 

323 1758 

83- 7 

171, 1 

48 2, 04s 

974 


324 174.8 

107. 4 

152-3 

61 1,417 

87a 

1 

Mean j 


! 


1, 6ti ±67 

8 gi±i 4 



Oct. 15 , *914 


Water Requirement of Plants 


41 


Table XXIV. — Water requirement of cucurbits at Akron, Colo., in jprj— Continued 


plaot and period of growth. 

Pot 

No. 

Dry 

matter. 

Dry 
i matter 
in 

fruit. 

; Water. 

Fruit. 

Water requirement 
based on — 

1 

Fruit. 

Dry matter. 

1913 - 

Cantaloupe, Rocky 
Eord {Cwumis melo), 
June 14 to Sept. 13. . 

Mean 

' 32s 

326 

327 

328 

329 

330 

Grawtr. 

314- 7 
285. 3 

2 11, 4 
264. 9 
272. 8 

305- 6 

Gram 5 . 

198. 9 1 

155 - 2 1 
92- 5 ^ 
132. 5 
160. 6 
162. 4 

Kilos. 

201. 7 
214. 4 
210. 5 
218. I 

197-3 
222. 8 

Per cent. 

63 

55 

44 

5 ° 

59 ' 

53 

1, 014 

1,382 

2, 276 

I, 646 

I, 228 

1,371 

641 

752 

996 

824 

723 

729 

i,486±i2o i 

778±34 

Watermelon, Rocky 
Ford (Citrullus vul- 
garis), June 14 to 
Sept. 13 

' 33 ^ 
3.32 
, 3 .S 3 

334 

335 j 

336 1 

301. 8 
318. S 
334 - 5 
314. 2 
267. 9 
320, 8 

193. 2 
] 216. 8 
225.9 
209, I 
159-4 
224. 2 

238. 2 

215 - 5 

241. 4 
232. 8 

232. I 

226. 5 

64 
68 
67 : 
66 

59 I 
70 

1,233 

995 

1, 069 

1, 112 

1,457 

1, 010 

790 

677 

722 

740 

866 

706 

Mean 

I, r46±49 

750 ±i 9 








On the basis of the production of fruit the watermelon has proven 
to be exceptionally efficient. The water requirement, calculated on the 
basis of the dry matter in the melons and reduced to inclosure conditions, 
was 91 5 ±39- The green fruit contained 95 per cent of water. The 
water requirement on a green basis would therefore be 46. 


RAPE, TURNIP, CABBAGE, AND POTATO 

Rape, turnip, cabbage, and two varieties of potato, the Irish Cobbler 
and the McCormick (PL VI, fig. 6), were included in the 1913 meas- 
urements (Table XXV). The water requirement, based on dry matter, 
was as follows : 


Crop 

Cabbage 

Turnip 

Potato: 

Irish Cobbler, 
McCormick. 
Rape 


Water 

539±7 

<539±3I 

659±is 



743±7 


Cabbage and tuniip are seen to have a lower water requirement than 
potato and to rank in efficiency with oats. Of the ‘potato varieties 
the Irish Cobbler was the more efficient and produced the most tubers. 

The McCormick, a late-maturing variety, produced fine vines but 
practically no tubers. The water requirement of rape was practically 
the same as that of turnip during the same period of growth, but the 
second crop, although not a heavy one, had a water requirement so 
much higher than the first that the combined crop is approximately 16 
per cent higher than for turnip. 



42 


Journal of Agricultural Research 


voi. ni. No. I 


Tabi^e XXV . — Water requirement of rape, turnip, cabbage, and potato at Akron, Colo., 

in IQI3 


Plant and period of ci'owth. 


2913 - 


Rape {Brassica napm), 
June 3 to July 19 


Mean, 


Rape, second crop, 
July 19 to Sept. 13. . 


Mean. 


Rape, combined crop, 
June 3 to Sept. 13 . . . 


Mean 


Turnip, Purple Top 

{Brassica rapa), May 
29 to July 19 


Mean , 


Cabbage, Early Jersey 
Wakefield (Brassica 
oleracea capitata), 
June 3 to vSept. 12. . . 


Mean. 


Potato, Irish Cobbler 
(Solanum tuber- 
osum), June 5 to 
Sept. 12 


Mean 


Potato, McCormick 
{Solanum tuber- 
osum), June 5 to 
Oct. 4 

Mean 


Put 

No. 

Dry 

matter. 

Tubers 
or roots. 

Water. 

Tubers 
or roots. 

Water requirement 
based on— 


Tubers or roots 

Dry matter. 

217 

Gravis. 

I 7 I. 2 

156- 3 

Grams. 

Kitos. 

Per cenL 


655 

658 

633 

693 

630 

671 





219 





140. 5 
171- 5 

164. 6 


97-4 







222 


no. 5 












657±6 







; 217 

44. 6 
68.5 

58.3 

63.8 


54 - 3 
69. 2 
58. 0 
53 - 2 
62. 8 



I 




li 010 

219 







834 

946 

382 





222 

69. 0 


60. 9 







!. 



98 i± 3 S 





217 

218 

215. 8 
224. 8 
220. 3 










767 

2ig 





204. 3 
237-9 

233- 6 


150. 6 

T-rn ^ 









/O / 

718 

. 222 


171. 4 












743 ±7 






’ 211 

212 

213 

214 
2^5 

, 216 

12S. 9 
128. 4 
58. 6 
128,5 
73-8 

90. 4 

69- 3 
64. 6 

17-3 
58. 8 
37 - 6 
29- 4 

78. 1 
90. 7 
30. 6 
69- 5 
51- 2 

68. 9 

54 

50 
29 

45 

51 
32 

1, 127 

1,403 

1,767 
r, 181 

1,360 

2, 341 

606 

706 

523 

541 

694 

762 

: 




I, 530^132 

<i 39 ± 3 i 





■ 205 
206 

284. 5 
281. 9 


148.9 








0*0 

569 

207 

359 - 8 
330. 7 
344 - 6 
313-2 


19° 5^ 



208 





209 
. 210 


^ 75 - 7 : 
r;;. 0 




53 ^ 




51a 

565 






^ ! i ' 1 1 



539 ±7 

' ^^3 

116 

117 

:i8 

119 
, 120 

170. 2 
203. 2 

2 11. 0 

222. 3 
2X8. 1 

201. 1 

40. 6 , 
67.8 ' 
81.7 
86. 6 
105-3 
52-4 

120. 4 1 

145- I i 

127. 0 1 
149-3 ! 
130, 0 1 

133-3 1 

24 ! 

33 

39 

39 

48 

26 

2, 966 

2, 140 

1.555 

1, 724 

1.234 

2, 542 

708 

714 

602 

671 

596 

662 

! 


i 

, 

A 1 

: 




059^15 

I 2 X i 

215. 8 

. I 

14 v 5 i 



674 

724 

683 

122 

213- 7 

I- 7 

154- 9 
146, 9 
164. 5 1 



123 1 

215- 5 

5 - 0 

2 


12^ 

219. 3 

10, 3 

5 


750 

766 

706 

125 

201. 4 

. 3 

154-2 ' 

145 - 9 i 



, 126 j 

206. 9 

1. 9 

I 1 


' 

1 



A. 

i 

' ' ' 1 

717*11 



Oct IS. J914 


IV ater Requirement of Plants 


43 


native and introduced grasses and other native plants 

'Two native Colorado plants were included in the 1912 measurements 
at Akron, Grindelia squarrosa^ or “gum weed,” and Artemisia frigida^ 
or “mountain sage” (PI. II, fig. 3). These plants were carried through 
the winter in the pots, and only two pots of each set were in good condi- 
tion in the spring. They both behaved as biennials, forming rosettes 
in 1911 ^nd flowering profusely in 1912. The data (Table XXVI) 
given for the period from May 20 to August 26 include much of the stored 
dry matter of the rosettes and root systems elaborated during an earlier 
period, and consequently the water requirement is somewhat too low. 
In order to check this, the data based on the total period of growth, 
which includes the growth and water consumption in 1911, have also 
been given. This method of computation increases the water require- 
ment less than 6 per cent. 

Table XXVI . — Water requirenieni of native plants at Akron, Colo., in IQ12 


Plant and jieruxi of growth. 

Pot 

Xo. 

Dry 

matter. 

W'atcr. 

Water re- 
quirement 
based on 
dry mat- 
ter. 

1912. 







Grams. 

Kilos. 


Grindelia squarrosa, May 20 to Aug. 26 

/ 163 

385-4 

172. 0 

446 


1 164 

367- 7 

180. 0 

490 





468 ±r8 

Artemisia frigida, May 20 to Aug. 26 

/ 167 

33 ^- 3 

153- 4 

456 


\ 168 

293- 9 

143- 9 

491 

Mean 




474 ±i 4 





TOTAL PERIOD OP GROWTH. 



1 


Grindelia stj^uarrt^sii, Aiig. 18, 1911,10 Aug. 26, 

if 

i 

I 399 - 6 

i 1S2. 4 

457 

1912 

\ 16 + 

j 381-2 

1 200. 5 

1 526 

Mean . . 


i 


492^29 





Artemisia frigida, Jan. 10, 1911, to Aug. 26, 

!/ 167 

372. 8 

177- 4 

! 476 



,l 

345- 8 

183. 9 

1 532 

s 


i 



* 504±24 

1 i 

i 


Although these are typical native plants of the high plains, they re- 
quired about 20 per cent more water tlian Kubanka wheat and rank 
higher in water consumption than any of the cultivated grains except 
rye and rice. 

Grasses produce so slowly that it is somewhat difficult to make satis- 
factory measurements of their water requirement. The 1913 experi- 
ments (Table XXVII) included pure buffalo grass, mixed grama and 



44 


Journal of Agricultural Research 


Vol. Ill, No. I 


buffalo grass, western wheat-grass, brome-grass, and a Siberian wheat- 
grass. Buffalo grass, brorae-grass, and wheat-grass each gave two 
crops, buffalo and grama mixed gave three cuttings, while western wheat- 
grass produced but one cutting. The combined crops afford the best 
basis for the comparison of these grasses. On the basis of the total dry 
matter produced throughout the season, the water requirement is as 
follows : 


Variety of gra.ss 

Buffalo 

Grama and buffalo. , 

Wheat-grass 

Brome-grass 

Western wheat-grass. 


Water rcQuirement 

308 i 22 

389^12 

70S±27 

I, oi6±2G 

. . . . , 1, 076it2g 


Brome-grass and western wheat-grass are comparatively very ineffi- 
cient in the use of water, requiring from 22 to 29 per cent more water 
than alfalfa. Western wheat-grass made a slow growth. WTieat- grass 
is more efficient than alfalfa, requiring 15 per cent less water. The short 
grasses made a wonderful showing, the water requirement of pure buffalo 
grass being only about one-third that of alfalfa, and that of grama and 
buffalo mixed, 47 per cent. The water requirement of buffalo grass is 
only 8 per cent above millet, which is one of the most efficient of the 
introduced plants. The mixed buffalo and grama grass required 36 per 
cent more water than Kursk millet. These arc the first of the native 
plants to show any marked efficiency in the use of water, although some 
of the weeds, as will be seen later, are also highly efficient. 


TablK XXVII . — Water requiremeni of native and introduced grasses at Akron, Colo., 

in jgi3 


Plant and period of growth. 

p 0 

Dry matter. 

Water. 

Water re^ 
quirement 
based oa 
dry matter. 

1913- 

Grama (Bouteloua gracilis) and buffalo grass 
(Bulbilis dacty hides), mixed, first crop, June 3 
to July 19 

139 

140 
, 141 

142 

^43 

144 

Cratns. 
50. I 
26. 9 
31-8 

21. 9 

22. I 

25-3 

Kilos. 

17.4 
10. 7 

12.4 
7- 5 
9-8 
8.6 

347 

398 

390 

342 

443 

340 

Mean 

377±Ti 

Grama and buffalo grass, mixed, second crop, 
July 19 to Aug. 26 

■ 139 

140 

141 

142 

H3 

1 244 

ST- 7 
35-4 
38.8 
37-9 
41. 2 
26. I 

18. I 

13. 2 
15-6 

14. 4 

16. I 

9-7 

350 

373 

402 

380 

391 

371 

Mean 

395 ± 7 







Oct. 15. * 9 M 


Water Requirement of Plants 


45 


TabI/IJ XXV^I . — tVafer requirement of native and introduced grasses at Akrony Colo., 
in igig — Continued 


Plant and period of growth. 

Pot 

No. 

Dry matter 

Water. 

^ 913 - 

Grama and buffalo grass, mixed, third crop, 1 

r 139 

140 

141 

142 

M 3 

144 

Grams, 

14.3 

II. 6 

ir. 8 

15-9 

15.0 

18.3 

Kilos. 

7-4 

6. I 

7.0 
7- 1 

7. 6 
4-3 

Mean 

Grama and buffalo grass, mixed, combined 
crops, June 3 to Oct. 20 

139 

140 

141 

142 

M 3 

144 

116. r 

73 - 9 
82. 4 

75-7 
78. 3 

69. 7 

42. 9 
30. 0 
35-0 
29. 0 

33 - S 
22, 6 

Mean 

Buffalo grass {Bulbilis, daciyloides) , first crop, 
June 18 to Aug. 26 . , . 

' 145 

146 

147 

148 

149 

1 150 

10. 0 
32. I 
18. 9 

12. 9 

13. 2 

8. I 

3 - 5 
9.0 

50 

. 3-8 
3-8 
I- 5 

Mean 

Buffalo grass, second crop, Aug. 26 to Oct. iS . . 

Mean 

’ 145 
146 
M 7 
. 148 

i 3-6 

i 3 - 1 

; 2.3 

S-2 

1 - 5 
.8 

I. 9 

Buffalo-grass, combined crops, June'18 to Oct. 18 . 

Mean 

f 145 

J 146 

1 147 

1 148 

13.6 

35 - 2 
21. 2 

18. I 

5-0 

9.8 

5 - 7 

5 - 7 

Brome-grass, S. P. I. 29880 {Bromxis inermis), 
first crop, Slay 23 to July ig 

f 133 
134 

1 136 

1 138 

64.5 

75 - 2 
76. 0 
60. 8 
79 - 5 

62. 8 
74. 6 
70-3 
58. 6 
79-3 

Mean 

Brome-grass, second crop, July 19 to Oct. 22. . . , 

Mean 

133 

134 
^ 135 

136 

138 

30 - 3 
46. I 
36. r 
26. 9 
40. 1 

28. 4 

59-3 
46.6 
21.8 
47 - 0 






Water re- 
quirement 
based on 
dry matter. 


517 

526 

593 

446 

507 

235 


471^26 


369 

406 

425 

383 

428 

324 


38g±i2 

350 

280 

264 


295 


185 


417 

258 

304 

365 


336±23 


368 

278 

269 

.315 


3 oS±i7 


973 

992 

925 

964 

99S 


97o4rg 


937 
I, 286 
I, 290 
810 
r, 172 


I, 099 + 76 



46 


Vol. m. No. I 


Journal of Agricultural Research 


Table XXVII . — Water requirement of native and introduced grasses at AkroUt Colo.f 
in IQlj — Continued 


Plant and period of growth. 

Pot 

No. 

Dry matter 

Water. 

1913- 

Brome-grass, combined crops, May 23 to Oct. 22 . 

Mean 

f 133 
134 
s 135 

1 138 

Grams. 

94.8 

121.3 

II2. I 

87.7 
119. 6 

Kilos. 

91. 2 
133- 9 

1 16. 9 
80.4 
126- 3 

Wheat-grass (Agropyroncristatum), S. P. 1 . 19537, 
first crop, June 5 to Tuly 10 

67 

68 

69 

70 

71 

72 

25-9 
33- 6 
24-3 

23.0 
17. I 
34- 0 

19. 2 
22. 4 

16. I 

19- 3 
13.8 
25. 8 

Mean 

Wheat-grass, second crop, July 19 to Oct, 22 ... . 

Mean 

67 

68 

69 

70 

71 

72 

49. 0 
77-0 
53- 6 j 
58. 0 
46. 1 
66. 2 

37.9 

45- I 
29-3 

40. 2 
34-8 

51-3 

Wheat-grass, combined crop, June 5 to Oct. 22 . . 

Mean 

67 

68 
, 69 

70 

7^ 

, 72 

74-9 
no. 6 

77-9 
81. 0 
63. 2 
100, 2 

57- I 
67- 5 
45-4 
59- 5 
48.6 
77. I 

Wheat-grass, western {AgroPyron Smithii), June 

17 to Oct. 22 

1 235 

236 

) 237 

1 238 
239 
t 240 

37- 7 
41. 4 

1S.3 

21. 1 

2 5. 6 
16. 7 

45- 0 
43- I 
15. 2 
23. 0 
28. 9 
19. 7 

Mean 






Water re- 
quirement 
based on 
dry matter. 


962 
z, 104 

1,043 

916 
I, 056 


I, oi 6 ib 26 


741 

667 

66-1 

839 


80S 

759 


746±2I 


773 

585 

547 

693 

755 

775 

688 ±3z 


763 

6 ro 


583 

735 


769 

769 


705^27 


1, 193 

I, 04.0 

831 

I, 087 
1, 128 


1, 179 


j, o76i2g 


WEEDS 

A number of weeds were grown in pots at Akron in 1913, in order to 
determine their water requirement. (Table XXVIII.) Most of these 
were planted late in the season, after the crops of grain had been removed. 
Pigweed and the annual sunflower were, however, started at the beginning 
of the season. Three crops of pigweed were produced, the water require- 
ment for the first, second, third, and combined cuttings, based on dry 
matter, being 325±io, 326±4, 278±7, and 32o±7, respectively. 



Oct. 15. 1914 


Water Requirement of Plants 


47 


Sunflower, which made an excellent growth, gave a water requirement 
of 705 ±8. Sunflower thus requires almost three times as much water 
as pigweed and 86 per cent as much water as alfalfa. 

A comparison of the water requirement of pigweed during the three 
periods of growth will show that the water requirement is not greatly 
affected by the period of growth. 

If this holds for the other weeds, no great error will be produced in 
comparing the water requirement of these plants without regard to the 
period during which they were grown. The water requirement is, how- 
ever, probably slightly less than it would have been if the plants had 
been grown in midsummer. The results obtained, based on the produc- 


tion of dry matter, are as follows ; 

Variety of weed Water requirement 

Purslane {Portulaca oleracea) 292 ±ii 

Pigweed {Amaranthus retroflexus) 3 20 ±7 

Cocklebur {Xanihium commune) 432 ±13 

Narrow-leaved sunflower from sand hills {Helianikus peiiolaris) . . 57o± n 

Annual sunflower {Heliantktcs annuus) 705^8 

Narrow-leaved sunflower from near Akron {Helianthus peiiolaris). 774 ±20 

Lamb 's-quarte cs{Chenop odium a Ibum) So r ± 4 1 

Fetid marigold {Boebera papposa) 881 ±26 

Western ragweed (Ambrosia ariemistfolia) 948^66 


Purslane and pigweed, two introduced weeds, appear to be excep- 
tionally eflicient plants, their water requirement being only slightly 
higher than that of Kursk millet and in practical agreement with the 
sorghums. Some of the indigenous weeds were also found to be fairly 
efficient, cocklebur, a plant found in stream beds and about ponds > 
having a water requirement 13 per cent less than wheat, while the narrow- 
leaved sunflower from the sand hills had a water requirement 31 per cent 
less than alfalfa. Lamb’s-quarters, an introduced plant, and fetid 
marigold (PI. VII, fig. 2) and western ragweed, indigenous plants, have 
a slightly higher water requirement than alfalfa. 

It is evident, therefore, that the "common weeds differ greatly in w'ater 
requirement. A growth of weeds in a crop or on summer fallow repre- 
sents a tremendous loss of moisture, a thousand pounds per acre of the 
most efficient weeds representing a loss of at least 1.5 inches of stored 
rainfall, or from 4 to 5 inches of stored rainfall in the case of the weeds 
having a high water requirement. The latter figures represent about 
the maximum amount of moisture that can be stored in fallow land. It 
is therefore easy to understand how the w’hole of the stored moisture 
supply may be lost through the growth of a moderate crop of weeds, and 
these varieties having a high water requirement are especially to be 
dreaded. 



48 


Journal oj Agricidiural Research 


Vol. in. No. I 


Table XXVIII . — Water requirement of weeds at Akron, Colo., in IQIJ 


riant and period of growth. 


1913- 

Sunfiover (Helianthus 
annum), June 5 to 
Sept. 15 


Sunflower, narrow- 
leaved (Helianihus 
peiiolaris), July 25 
to Sept. 17 


Mean. 


Sunflower, narrow- 
leaved {Helianthus 
peiiolaris), fro m 
Sand hills, Aug. 13 
to Sept. 18 


Mean. 


Pot 

No. 


273 

274 

275 

276 


175 

176 

177 

178 

179 
I So 


Marigold, fetid ( Boe- 
bera papposa), July 
25 to Sept. 17 


169 


Tamb 's-quarters {Chen- 
opodium album), 
July 25 to Sept. 17. 


Ragweed, western 
{Ambrosia artemisi- 
folia), Aug. I t(j 
Sept. j8 


Mean. 


2 1 1 

212 

213 

214 

215 

216 


Dry 

matter. 


Crams. 

516.6 
554.0 
502. 2 

459-2 

512.5 

507.2 


196. o 
140.4 
148. 7 
103. 4 
1 56. o 
163. 7 


32.3 

34 6 
14. 4 

25-4 
30- 5 


1 16. o 
102. 8 
106. 5 
99-9 
167. 3 
55-0 


64. o 
35-3 
47- 4 
40. o 
51.6 
64. 2 


17. I 
12.3 
10. 6 
20. 6 

13- 

27- 5 


Grams. 
40. 7 
70. 5 
51. 8 

58.4 

63. o 
63. 2 


34 I 
19, 6 

23-3 

16. 7 
21.8 
25. 2 


Kilos. 

373- 5 
363. 9 
343- 2 
334 9 
371. 6 
360.9 


135- 5 
103. I 
109. 5 
87.1 
132. 2 
129. 6 


10. o 
18. 6 
18. 2 
9- 1 
13. 5 


Per cen t- 
8 
13 


95- 
98.8 
93' 3 
86. 7 


^25- 5 
55 ' 


Water requirement 
based on— 


g, 180 

5, 161 

6, 625 

5,72s 

5» 90° 

S> 7 io 

6, 384 ±3^3 


3 , 9/1 
5, 261 
4,695 

5, 218 

6, 061 

5, 141 


5,058^132 774 ± 2 o 


705^8 


585 

576 

526 

632 

531 

567 

• I S 7 o±ii 


826 
96a 
876 
868 
750 

5-2 1 ;i,oo 4 


39 - 9 
26. 9 

46. 2 

33 - 4 

47. 2 
44-6 


12 * 5 
12. 9 
13.8 
18. 7 


.f S 8 i ±26 


624 

762 

975 

^^35 

914 

694 


801 ±41 



948 ±66 



Oct. IS. 1S»4 


Water Requirement of Plants 


49 


Tablb 


XXVIII . — Water requirement of weeds at Akron, Colo., in igij — Continued 


Plant and period of ^oTrth. 


1913- 

Pigweed (Amaranthiis 
retrojlexus), June 12 
to July 19 


Mean. 


Pigweed, second crop, 
July ig to Sept. r.. . 


Pigweed, third crop. 
Sept. I to Oct. 4. . , 


Mean. 


Pigweed , comb ined 

crops, June 12 to 
Oct, 4 


Mean. 


Purslane {Portulaca 
oleracea), July 18 to 
Sept. 17 


Purslane, Aug. 21 to 
Sept. 17 


Moan , 


241 

242 

243 

244 

245 

246 


Dry 

matter. 


Grams. 

56-9 

^33- 7 
145- 7 
115. o 
112. 8 
161. 5 


74. 9 
62. 2 
50. o 

54.9 

60. 9 
50. 6 


7- .<5 

II. 6 
II. 8 

16. 7 
14. 9 
18. 6 


139- 3 
207. 5 
207. 5 
186. 6 
18S. 6 
230. 7 


36. 2 
28. o 
33- 5 
38 - 4 
48- 5 
18.8 


Kilos. 
18.8 
!;o. 2 

44. 6 

33- 7 
33- 5 
55- 7 


22. 5 
20. I 

16. 4 

17. 9 
20. 5 
17. 2 


43- 5 
73' 9 
64. 4 
55-8 
57-9 
77.8 


Water requirement 
based oa — 


330 

377 

306 

293 

297 

345 


325±ro 


300 

323 

328 

326 

337 

340 

326±4 


293 

3^0 

288 

251 

262 

^63 

278±7 


312 

35 ^> 

310 

299 

307 

337 


246 

268 

289 

284 

266 


292 ± II 


RELATIVE WATER-REQUIREMENT MEASUREMENTS 

The relative water requirement of the different varieties of plants 
grown at Akron in 1912 is siniuiiarized in Table XXIX, Kubanka wheat 
being used as a basis of comparison. Grimm alfalfa is seen to have the 
highest water requirement of the 42 species and varieties tested during 
1912, while Kursk millet proved the most efficient of all the plants 
tested. The varieties are also grouped on the basis of crop or genus, and 
their mean water requirement compared with the mean water requi re- 
60300®— 14 4 



50 


Journal of Agricultural Research 


Vol. 111. No. t 


ment of the wheat varieties. The relative water requirement on this 
basis is given in the last column of Table XXIX. 

The quantity of water required by the various crops for the production 
of a unit amount of seed or grain at Akron in 1912 is summarized in 
Table XXIV. Rye is seen to be the least efficient of the grain -producing 
crops tested, with Voronezh proso the most efficient. 

Table XXIX . — Summary of uater-requirement measurements at Akron, Colo., in igi2 
WATER REQUIREMENT BASED ON DRY MATTER PRODUCED 


Crop and variety. 


Botanical name. 


1912. 


Alfalfa: 

Grimm, S, P, I. 

25695- 

Grimm, A. D. I. 

E. 23-^0-52. 

Clover, sweet 

Rice, Honduras 

Chick-pea 

Rye , spring 

Cotton, Triumph 

Native plants 


Medicago sativa . , . , 

do 

Melilotus alba 

Oryza sativa 

Cicer arietinum ... 

Secale cereale 

Gossypium hirsu- 
tum. 

Artemisia frigida . . 
Grindelia squarrosa 


Oats: 

Sixty- Day 

Biut 

Swedish Select — 

Canadian 

Barley : 

Hanncheu 

White Hull-less. . . 

Beldi 

Beardless 

Wheat: 

Spring Ghirka .... 
Marvel Bluestem. . 

Emmer 

Kubanka 

Kharkov 

Turkey 

Sugar beet: 

Klein wanzleben. . 
Com: 

China White 

Iowa Silvermine. , 

Laguna 

China White X La- 


Avena sativa 

.... do 

... .do 

do 

Hordeum distlchon. 
Hordeum vulgare . . 

... .do 

do 

Triticum aestivum. . 

do 

Triticum dicoccum . 

Triticum durum 

Triticum aestivum. . 
do 

Beta vulgaris 

Zea mays 

do 

do 

do 


guna. 

Hopi 

North western 
Dent. 

China WhiteXHs- 
peranza. 

Bsperanza 


do. 

do. 

do. 

,do. 


Water requirement of — 

Variety. j 

Crop (or genus). 

Actual, 

Relative. 

compared 

with 

Kubanka 

wheat. 

Actual. 

Relative, 

compared 

with 

wheat 

{Triticum 

Spp). 

659±6 

657 ±ii 

I. 67 ±0. 03 

1- 67± . 04 

1 658 

I, 60 

63S±4 

5 i 9 ±i 3 
5io±i4 
496 ±9 
488 ±14 

I. 62 i . 03 
I. 32± . 04 
I. 29± . 04 
I. 26± . 03 
I. 244 ; . 04 

638 

519 

.510 

496 

488 

1. 56 
I. 27 
I. 24 

I. 21 
I. 19 

474ii4 
46S i 18 

I. 2oi . 04 
I. r9± .05 

47. 

I- 15 

491 ±13 

449 ±3 
423 ±5 

399 ±6 

I. 25 ± . 04 
I. 144 : - 02 
I. 07 4; * 02 
I. 01 4 : . 02 

441 

1.08 

443 ±3 
439 ± I 
4 i 6±4 

403 ±8 

I. 12 4 ; . 02 
I. II i: .02 
I. c6± . 02 
I. 02 4 : . 03 

■ 425 

I. 04 

457±3 

428±3 

394±7 
365^:6 
364 ±6 

I. i 64 ; . 02 
I. 144 : . 02 
I. 094; .02 
I. 00 

. 934 : .02 
.924: .02 

► 410 

I. 00 

32i±8 

. 8 r 4 : .03 

321 

.78 

3 i 5±7 
302 i 7 

29 S ±6 

289±4 

. 8oi . 02 
. 77± -02 
. 75i -02 
• 73± -02 



285 ±7 
28 o±IO 

• 72 4 : .02 

• 714: .03 

> 286 

■ 70 

2SO±2 

.63± .01 



2.39 ±3 

. 6 i 4 : . 01 





Oct. 15, 19*4 


Water Requirement of Plants 


51 


Table XXIX . — Summary of water-requirement measurements at Akron, Colo., in 
ip 72 — Continued 


WATER requirement BASED OK DRY MATTER PRODUCED — Continued 




Water requirement of — 



Variety. 

Crop (or genus). 

Crop and variety. 

Botanical name. 

Actual. 

Relative, 

compared 

with 

Kubanka 

wheat. 

Actual. 

Relative, 

compared 

with 

wheat 

iTTilicum 

spp). 

1912. 

Sorghum : 

Andropogon sor- 
ghum aetliiopicus. 
Andropogon sorghum 
do 

359 ±2 

273±4 

259±5 

255±3 

249^3 

239±2 

237 i 4 

223±1 

248^7 

i 87±2 

208 it 
206 ± I 

0. Qi io. 02 

. 69± ,02 



j 

Milo, Dwarl .... 



Kafir, Blackhull . 
Durra, White 



. . do 


262 

0. 64 

Milo 

. , . . do 

. 63 ± .02 

. 61 ± . OJ 

Minnesota Amber. 

do 



Red Amber ...... 

. , . . do 

, 6oi .01 



Kaoliang, Brown. . 

do 

. 57 ± .05 

. 63 i .02 
. 47 ± • 01 

• 53 ± .01 
, S2± . 01 



Millet; 

German 

Kursk 

i ! 

! Chaetochloa italica . 

! do 

218 

207 

} 

• 53 
•SI 

• 51 

Proso: 

Tambov 

Voronezh 

1 Panicum miliaceum 
! . . . . do 


1 

1;^ 



WATER REQUIREMENT BASED OK GRAIN OR SEED PRODUCED 





T. 6r ±0. 08 



I, 348^114 

I, 4r6± 119 
I, 224±55 

I, I 72 ±i 33 
' i,io3±i8 

1 

b 573±49 

I. 2I± - II 

Oats: 


I. 27± . 12 1 
r. io± . 07 1 

Burt 


Sixty-Day 


I- o 5 i -12 1 



. 99± . 04 J 

I. 42 ± .06 

Wheat: 

Marvel Bluestem. . 

Triticum aestivum. . 



j i, 468±34 

1 I. iii ±37 

1 i,o64±6o 

r. 32i . 06 

I. 00 

Kubanka 

Triticum dunim ... 

Kharkov 

Triticum aestivum. . 

. gdi . 06 

Turkey 


1 995±22 

984^18 

. Qoi . 04 
. &g± . 03 . 

Emmer 

Triticum dicoccum . 

Barley : 


White HuU-lcss. . . 

Hordeum 'vulgarc . . . 

I, 239±ii 

I. ii± .04 

Beardless 

do 

I, oi 7 ±S 3 

I, oo 5±36 

. g2i .08 
. qo± . 04 

Hannchen 

Hordeum distichon 

Beldi 

Hordetim vulgarc . . . ' 

941 ±10 

. 84± - 03 , 

Sorghum: 


Kaoliang, Brown. . 

Androjx)gou sor- 

ghum. 

.do 

927^38 

. 04 | 

Minnesota Amber 

6 o 7 ±i 5 

1 

• SS± -02 J 

Millet: 


Kursk 

Chaetochloa italica . 

483 ±n 

0 

41 

Proso: 



Tambov 

Panicum miliaceum 

482 ±9 

.43± .02I 

Voronezh 

. , , .do 

425±4 

• sSi .oij 





I. 50 

I- 13 


.64 

■ 41 

.38 



52 


Journal of Agrictdtural Research 


Vol. m, No. 1 


The relative water requirement of the different varieties included in the 
1913 experiments will be found summarized on the basis of dry matter 
in Table XXX and on the basis of grain production in Table XXXI . 
Fifty -five species and varieties were included in these measurements. 
Reference to these tables will show that a number of plants had a higher 
water requirement than alfalfa, heretofore the most inefficient in the use 
of water of any plant included in these experiments. On the other hand, 
millet maintains its supremacy as the most efficient plant so far included 
in the water-requirement measurements. 

Tablj? XXX . — Summary of water-requirement measurements at Akron, Colo., in 1^13, 
based on dry matter prodiieed 


Crop and variety. 


Botanical name. 


I Water require* 
ment. 


Relative, as 
compared 
with Kubanka 



wheat. 

,076^29 

2. lyio 

. 06 

, Ol 6 i ;26 

2. IO± 

. 06 

948 ± 66 

i 

■ 13 

935±9 

I I > 89 i 

•03 

905 ±25 

T. 82± 

•OS 

881 ±26 

I. 78 i 

.06 


: i.68± 

.04 

834 ±S 

I. 68± 

. 02 

8i5±25 

I. 64 ± 

•05 

805 ±8 

1 I- 62 db 

. 02 

801 i 41 

I. 62 i 

.08 

789±9 j 

I- 59 ± 

. 02 

78o± 19 

i- 57 ± 

.04 

7 / 5±5 

^ 1. 56 ± 

■ 02 

774 i 2 o 

; 1 . 56i 

.04 

773±8 

1 I- S ^± 

. 02 

772 ±ii 

I- 56 ± 

•03 

748 8 

1 i. 5 i± 

. 02 

744 ±i 7 

1 1. 5o± 

. 04 

743 ±7 

I- 5 o± 

. 02 

7 i 7 ±i^ 

i I. 45 ± 

■03 

7 i 3 ±ii 

: i- 44 ± 

•03 

705 ±8 

, I. 42 ± 

. 02 

705±27 

, i* 4 ii 

. 06 

69o±8 

: i- 39 ± 

. 02 

682 ±4 

1 

. 02 

672 i 9 


. 02 

^59^15 

i- 33 ± 

•03 

657 ±ii 

i- 33 ± 

•03 

65r±i2 

I- 

•03 

639 ±31 

I. 29± 

. 06 

62 I ±27 

I. 25 db 

. 06 

6 i 7 i 9 

I. 24 ± 

. 02 

6 r 7±5 

I. 24 ± 

.02 

6ooihi5 

I. 2J± 

-03 

571 ±3 

r.iS± 

, or 

570±ii 

i.iS± 

• 03 

539 ±7 

1. 09± 

. 02 

49 <^±S 

I. 00 


432 ±13 

. 87 ± 

.03 


1913- 

Wheat-grass, western 

Bromc-grass 

Ragw'eed, western 

Vetch, purple 

Flax 

Marigold, fetid 

Pumpkin, ! 

Alfalfa, Grimm 

Soy bean, wild 

Clover, crimsijn 

Lamb 's-qiiarters 

Clover, red 

Bean, horse, S. P. 1 . 15429. , . 

Pea, Canada field 

Sunflower, narrow leaved . . . 

Bean, Mexican 

Bean, horse, S- P- I. 2 q 

Squash 

Rice, Honduras 

Rape 

Potato, McCormick 

Cucumber 

Sunflower, annual 

Wheat -grass 

Vetch, hairy 

Bean, nH\’y 

Bean, soy, cultivated 

Potato, Irish Cobbler 

Cotton, Triumph 

Alfalfa, Peruvian 

Turnip 

Cantaloupe 

Oat: 

Swedish Select 

Burt 

Watermelon 

Cowpea 

Sunflower, narrow'-l e a ve d, 
from sand hills. 

Cabbage 

Wheat, Kubanka 

Cocklebur 


Agropyron Smithii 

Bromus inermis 

Ambrosia artemisifolia . 
Vicia atropurpurea . . . . 
Linum usatissimum. .. . 

Boebera papposa 

Cucurbita pepo 

Medicago sativa 

Glycine soja 

Trifolium incamntum . . 
Chenopodium album. .. 

Trifolium repens 

Vicia faba 

Pisum sativum 

Helianthus petiolaris. , 
Phaseolus vulgaris. . . , 

Vicia faba 

Cucurbita maxima. , . . 

Or^-^za sativa 

Brassica napus 

vSolanum tuberosum . . . 

Cucumbis sativa 

Hellajithus annuus 

Agropyron cristatum, . . 

Vicia villosa 

Phaseolus vulgaris, . . . 

Glycine hispida 

Solanum tuberosum . . 
Cjossyjiium hirsutum , 

Medicago sativa 

Brassica rapa 

Cucumis melo 


A vena sativa 

do 

CitruUus vulgaris 

Vigna sinensis 

Helianthus petiolaris . 


Brassica oleracea capitata, 

Triticum durum 

Xanthium commune 



Water Requirement of Plants 


53 


Table XXX. — Summary of water requirement measurements at Akron, Colo., in igi^, 
based on dry matter produced — Continued * 


Crop and variety. 


1913- 

Com: 

China White 

Bloody Butcher 

Northwestern Dent . , 

Teosinte, Durango 

Crass, buffalo and grama. 

China White X Teosinte . . 
Com: 

Hopi 

China WhiteXHopi. . 

Indian Flint 

Pigweed 

Grass, buffalo 

Sorghum: 

Minnesota Amber, . . 
Red Amber 

Purslane 

Millet, Kursk 


Botanical name. 


Zea mays 

. . . .do 

. , . .do 

Euchlene mexicana 

Bulbilis dactyloidcs and 
Boutelona gracilis. 


Zea mays 

do 

. . . -do 

Amaranthus retroflexus. , 
Bulbilis dactyloidcs 


Andropogon sorghum . 

. . . .do 

Portulaca oleracea 

Chaetochloa italica . . . 


Water require- 
ment. 


415^4 

405 ±7 
399 ±i 2 
3QO±ir 
3891b 12 

376±4 

345 ±3 
342 ±5 

320±7 

3o8±37 

298^:2 
2961b I 

292 ±II 

286 ±4 


Relative as 
compared 
with Kubanka 
wheat. 

0. 84^:0 

. 01 

.82i 

02 

. 80 -b 


• 79 ± 

02 


•03 

. 76 ± 

01 


02 

. 70 ± 

01 

. 691b 

. 01 

■6s± 

. 03 

. 6i± 

.04 

. 6oi , 

. 01 

■ 59 ± ■ 

, 01 

■ 59 ± ■ 

. 02 

■ 5 a± . 

. 01 


Table XXXI. — Summary of water-requirement measurements in igij based on grai 
tubers, roots, or fruit Produced 


Botanical name. 



Crop and variety. 


Sunflower: 

Annual 

Narrow-leaved 

Flax 

Pea, Canada field 

Bean, soy 

Potato, Irish Cobbler 

Bean, Mexican 

Oats, Swedish Select 

Cantaloupe 

Bean, Navy^ 

Oats, Burt 

Cucumber 

Cowpea 

Turnip 

Wheat, Kubanka 

Com, Northern Dent 

Watermelon 

Sorghum, Red Amber 

Com, Indian Flint 

Sorghum, Minnesota Amber . , 


Helianthus annuus 

Helianthus petiolaris . . . 
Linum usitatissimum . . . 

Pisum sativum 

Glycine soja 

Solanum tuberosum . . , . 

Ph:iscoliis vulgaris 

Avenasativa 

Cucumis mclo 

Phaseolus vulgaris 

Avena sativa 

Cucumis sativa 

Vigna sinensis 

Bra^ica campestris 

Triticuin durum 

Zea mays 

Citnillus vulgaris 

Andropogon sorgum 

Zea mays 

Andropogon sorghum. . . 


Relative water 
requirement 
compared 
with Kubanka 
wheat. 


' 6, 384 ±383 

4 - S3±0. 29 

5, 058 ±132 

3 - 83 i 11 

2, 835^52 

2. i4± .05 

2, 322 ± 121 

I. 764: , 1 1 

2, 053 ±51 

r- 55 ± -04 

2, 027^197 

I. 534 : . 16 

r,8SS±62 

i. 43 ± -05 

I, 8764:55 

1 - 414 : .04 

i, 824±237 

I* 38± .18 

I. 646 ±36 

I. 25± .03 

1, 641 ±33 

I. 24± .03 

I, 61 r ±67 

I, 22 4 : . 05 

b 576 ±32 

I. ipdb • 03 

I, 5304:132 

‘l. l64; . 10 

I, 322 ± 16 

1. 00 

I, 241 4:77 

. 044 ; .06 

I, 1464:49 

.874: .04 

1, ioo4:3T 

• 83 ± .03 

854 ±31 

.6 54: ,01 

765 ±12 

. 5S± . 01 



54 


Journal of Agricultural Research 


voi. ni. No. X 


COMPARISON OF THE WATER REQUIREMENT OF CROPS AT AKRON, 
COLO., IN 1911, 1912, AND 1913 

Climatic conditions at Akron during the summer of 1912 were less 
severe than during the preceding summer. The rainfall in 1912 was much 
greater than in 191 1 , the temperature was lower, and the evaporation was 
less. These conditions were apparently due in part to a marked reduc- 
tion in the intensity of the solar radiation at the earth's surface following 
the eruption of Mount Katmai, Alaska, early in June, 1912, the dust 
from which produced a haze in the upper atmosphere. Abbot and Fowle 
(1913) obs^i^'^ed a maximum reduction in the solar radiation of about 20 
per cent at Bassour, Algeria, and at Mount Wilson, Cal., Kimball (1913a, b) 
reports an average reduction of 17 per cent in the intensity of the solar 
radiation at Mount W eather, Va. , during the last half of 1912, while Briggs 
and Belz (1913) have shown that there was a general reduction in the 
evaporation from a free -water surface during the summer months follow- 
ing the eniption. It is consequently of interest to detcmiinc whether the 
diminution in the intensity of the solar radiation was accompanied by a 
reduction in the water requirement in 1912. Such a comparison is possi- 
ble in connection with the Akron experiments, since a large numl^er of the 
varieties employed in the experiments of 1911 were also included in the 
1912 measurements. All varieties showed in 1912 a marked reduction 
in the water requirement as compared with 1911. The measurements 
for each year are given in Table XXXII, together with the ratio of the 
1912 to the 1911 measurements. The 1912 measurements show" an aver- 
age reduction in the water requirement of 21 ± 2 per cent for the 25 varie- 
ties tested during both years. The individual ratios fluctuate somewhat, 
doubtless owing in part to errors of experiments,^ but in part also to the 
different response of individual varieties to changed climatic conditions. 

1 It should be mentioned here that the plants -were fertilized in 1913 and not in 1911. This is a matter of 
importance in this connection, because it is well established that any deficiency in plant food increasca 
the water requirement. The effect of the addition of fertilizer on the water requirement was measured 
both years. The use of fertilizer resulted in a slight redtirtioa {6±2.3 per cent) in the water requirement 
of Kubanlca wheat at Akron in 1911, comparing pots 7 to ra, fertilized, with pots i to 6, unfertilized. These 
pots stood side by side in the inclosure. (.See Briggs and Shantz, 1913a, p. 19.) In igra the fertilized 
Kubanka wheat plants showed a slight increase in water requirement— namely, 5^2.3 per cent, compar- 
ing pots I to 6 against pots 7 to 12. The differences in each instance ate without significance when the 
errors arc considered and are furthermore of opposite sign, so that the addition of fertilizer may be con- 
sidered to have had no effect on the water requirement, so far as Kubanka wheat was concerned. Rich 
surface soil from the same source was employed in the experiments of both years. 



Oct, IS. 


55 


Water Requirement of Plants 


TablB XXXII . — Comparison of water-requirement measurements at Akron, Colo., in 
I pi I and 2 pi 2 


Crop. 

Water requirement. 

Ratio, rqia 
to rgii. 

1911. 

191a. 

Wheat: ' 




Kubanka 

468 ±8 

394 ±7 

0. 84 ±0. 02 

Bluestem 

53 i ±5 

45?±4 

. 85^ .01 

^ring Ghirka 


457±3 

- port . 01 

^nmer 

534 ii 4 

428±3 

. 8o± . 02 

Oats: 




vSixty-Day 

605 ±5 

491 ±13 

.Sri .03 

Burt 

639 ±7 

449 ±3 

. 70± . 01 

Canadian 

S 98 ±i 4 

399 ±6 

.67=!: .02 

Swedish Select 

6 is ±7 

423 i 5 

. . 01 

Barley: 




Haniichen 

527±8 

443 ±3 

. 84i .01 

Beldi 

543 ±2 

4 i 6±4 

. 76± . 01 

White Hull-lcss 

542 ±3 

439 ± I 

. 8i± ,01 

Beardless 

S 44±9 

403 ±8 

. 74 ± . 02 

Rye, spring 

724±7 

496 ±9 

. 69^; . 01 

Northwestern Dent 

368±io 

28oi 10 

1 

■ 75 ± - 03 

Iowa Silvermine 

420±3 

302 ±7 

i . 72 i: .03 

Rsperanza 

‘ 3 i 9±5 

239±3 

i . 7 g± . 01 

Sorghum; 




Red Amber 

298^4 

237±4 

. 8o± . 02 

Milo, Dwarf 

333 ±3 

273±4 

. 82 i .02 

Kafir, Blackhull 

27 «i 5 

259±5 

- 93 ± .03 

Durra, White 

32I±2 

255±3 

. 79± -01 

Kaoliang, Bro^ra 

3 oi ±3 

223 ±I 

- 74 ± . 01 

Millet, German 

263 ±15 


.94± .05 

Legumes; 




Alfalfa 

1, 068 i 16 

659 ±6 

.62± .03 

Clover, Sweet 

709±9 

638^4 

. 90± . 02 

Beet, sugar 

377±8 

32i±8 

.85± .03 

Mean water-re quire ment ratio for igi2 to 


[ 


1911 




Mean evaporation ratio for June, July, and 



• /9 

August, 1912 to 1911 



* 75 ± -03 


1 


Evaporation measurements from a frec-water surface at Akron are 
also available for 1911 and 1912 (Briggs and Belz, 1910, p. 17). The 
ratio of the evaporation in 1912 to that in 1911 by months is as follows: 
June, 0.69; July, 0.7S; August, 0.79. The average ratio during these 
three months is 0.75^0.03. This corresponds to a reduction of 25 ±3 
per cent in evaporation as compared with a reduction of 21 ±2 per cent 
in the water requirement. The change in the water requirement of 
these 25 varieties taken together is seen to be in approximate agreement 
with the change in evaporation from a free-watcr surface. A consid- 
eration of the individual ratios indicates, however, that different varie- 
ties may respond quite differently to the same change in climatic con- 
ditions. 

To investigate further the variation in water requirement due to 
differences in climatic conditions, a number of varieties were also 



56 


Journal of Agricultural Research 


Vol. in. Ko. I 


included in the measurements of both 1912 and 1913. The ratios of 
the water requirement of these crops in 1912 to that in 1913 are given 
in Table XXXIII. Similar ratios are also given for crops grown in 
1911 and 1913. It will be seen that the mean 1913-1911 ratio approxi- 
mates unity; in other words, the mean water requirement of the crops 
under investigation was practically the same for both years. The 
water requirement in 1912 is seen to be far below the 1913 value, the 
mean ratio being 0.75^0.01. The mean ratio of the monthly evapora- 
tion for June, July, and August, 1912, compared with 1913,13 o.8o± 
0.02, which is in approximate agreement with the ratio of the water 
requirement of crops grown during the two years. 

The crops at Akron as influenced by climatic conditions in 191 1, 1912, 
and 1913 may then be summarized as follows: 

Tabl^ XXXIII.— Cow/jomon of the water requirement of ike same crops at Akron, 
Colo., igii, Jgi 2 , and 


Water requirement. 


Wheat, Kubanka 

Oats: 

Swedish Select 

Burt 

Com: 

Northwestern Dent. 

Hopi 

China White 

Sorghum : 

Minnesota Amber. , . 

Red Amber 

Millet, Kursk 

begumes; 

Alfalfa, Grimm 

Pea, Canada held . . , 
Potato, Irish Cobbler. . . . 

Cotton 

Rice 


46Si;8 

6 i 5±7 

639 ±7 
368^10 


298 ±4 


I, 068 i 16 
Sooih 17 
44 ^±ii 


Mean water requirement j 

ratio I 

livaporation in inches for I 
three summer months. 


28. 46 


394±7 

423 ±5 
449 ±3 

28oilO 

285±7 

3 r 5±7 

239±2 

237±4 

i87±2 

657±ii 


488 i 14 
496 ±9 


496^5 

6 i 7±9 

6 i 7 ±S 

399 ±i 2 

4 r 6±4 

2984:2 
296 ± I 
286±4 

775±5 

<^ 39 ±i 5 

744±i7 


26. 75 


I. 06 

I. 00 
‘97 

I. 08 


.99 


*77 

•97 

1.47 


I. o4±. 04 
. 94 ± • 04 


o. 80 

69 
73 

70 
80 

76 

80 

80 

66 

79 


75 

67 

75±oi 

8o±02 


The conditions during 1911 and 1913 were such as to give rise to prac- 
tically the same water requirement. The water requirement of crops 
grown in 1912 was on the average only 79^2 per cent of crops grown in 
1911 and 75±2 per cent of crops grown in 1913. Therefore, in order to 
determine the relative water requirement of the different crops, it appears 
justifiable to iticrease the 1912 water requirement ratios by the reciprocal 
of 0.77 — namely, 1.3. This procedure has been followed in the summary 



Oct. 15. >914 


Water Requirement of Plants 


57 


table (Table XXXIV), which places the water requirement of all crops 
upon the basis of years similar to 1911 and 1913. When the water- 
requirement measurement of any particular crop extended over more 
than one year, the mean value of the several water- requirement deter- 
minations is given in Table XXXIV. 

SUMMARY 

This paper deals with the measurement of the water requirement of 
plants at Akron, Colo., in the central portion of the Great Plains. The 
term “water requirement” is here used to express the ratio of the water 
absorbed by a plant during its period of growth to the dry matter pro- 
duced. The plants were grown to maturity in large galvanized-iron pots 
having a capacity of about r 15 kg. of soil.^ Each pot was provided with a 
tight-fitting cover having openings for the stems of the plants, the annular 
space between the stem of the plant and the cover being sealed with wax. 
The loss of water was thus practically confined to that taking place 
through transpiration, and the entrance of rainfall was almost wholly 
prevented. The pots were weighed two or three times weekly to deter- 
mine the amount of water required to maintain normal weight. Water 
was delivered from 2-liter calibrated flasks through stoppered openings in 
the middle of the cover to a 5-inch flowerpot sunk in the soil immediately 
beneath the cover. 

To protect the plants from birds and severe wind and hail storms, it 
was found necessary to conduct the experiments in a screened inclosure. 
Pyrlieliomctric measurements showed that the inclosure reduced the 
radiation about 20 per cent. Water-requirement measurements con- 
ducted simultaneously wdth the same plants inside and outside the 
inclosure showed that the inclosure also reduced the water requirement 
approximately 20 per cent. 

Rich surface soil was used in the pots, and the pots were also fertilized 
to insure an adequate supply of plant food. Six pots of plants of each 
variety were used, and the water requirement of each pot was deter- 
mined independently, in order to provide a basis for the determination 
of the probable errors of the experiment. 

The detailed results given in the paper comprise measurements of 44 
species and varieties in 1912 and 55 in 1913. The writers’ 191 r measure- 
ments have also been included in the summary table. The years 1911 
and 1913 were similar in cliaractcr, and the same plants grown during 
both years gave practically the same water requirement. 'The year 
1912 was cooler and the evaporation and light intensity were much 
lower. These conditions had a marked influence on the w^ater require- 
ment, the mean water requirement in 1912 being only 77 per cent of 
that in 19H and 1913. In order to place all of the determinations 
upon a comparative basis, the 1912 mcirsuiemeiits have accordingly 
been increased 30 per cent in the siuuinary table (Table XXXIV). 



Vol. Ill, No. 1 


58 Journal of Agricultural Research 


TablS XXXIV . — Summary of water-requirement determinations at Akron, Colo., in 
igil, IQI2, and igis, based on the prodxiciion of dry matter 


Plant. 

Botanical name. 

Num- 
ber 
of ob- 
serva- 
tions. 

Water requirement. 

Of spedes or 
variety. 

GRAIN CROPS. 




Proso: 


Years. 


Voronezh, C. I. 16 

Panicum railiaceum 

1 

268±i ] 

Tambov, S. D. 366 

do 

I 

270±l } 293 

Black Voronezh, S. D. 334.. 

do 

I 

341 ±10 j 

Millet; 




Kursk, S. P. I. 30029. . . . 

Chaetochloa italica 

I 

261^15 

Kursk, S. P. I. 34771 

do 

2 

265^3 

Kursk. S. P. I. 22420 

do 

I 

287±2 ■ 310 

German, S. P. I. 2684:5 . . . . 

do 

2 

293 ±9 

Turkestan, S. P. I. 20694. . . 

do 

I 

444 ±9 

Sorghum: 




Kafir, Dwarf Blackhull, 

Andropogon sorghum 

1 

285 ±3 

C. I. 340. 




Kaoliang, Brown, S. P. 1. 

do 

2 

296it2 

24993- 




Kafir, White, C. T.370. . . . 

do 

I 

297±4 

Red Amber, S. P. I. 17363 . 

do 


301 i2 

Kafir, Early Blackhull, 

do 

I 

302 ±13 

C. 1.472- 




Minnesota Amber, A. D. I. 

do 

2 

305±2 

341-13- 




Kafir, Blackhull, S. P. I. 

24975- 

do 

2 

. 322 

Milo.WTrite, C. I. 365 

do 

I 

3i7±3 

KafirXDurra, C. 1. 198- 

do 

I 

32i±5 





Fetenta, C. I. 182 

do 

I 

323±4 

Milo, S. P. I. 24960 

do 

I 

324±4 

Durra, Wliite , S. P . I . 

do 

1 

327±2 

24997. 

1 



Milo, Dwarf, .S. P. I. 


2 

344±3 

24970. 




Sudan grass, S. P. I. 

; do 

I 

467±9 . 

25071. 




Com: 




Esperanza 

Zea mays 

2 

3i5±3 

China WhiteX Esperanza. 

do 

1 

325±2 

Indian Flint 

' do 

I 

342 ±5 

China White XHopi 


I 

345±3 

Hopi 

do 

3 

361 ±6 

China WhiteXLaguna, . . . 

do 

I 

376±5 

Northwestern Dent 

do 

3 i 

377±7 

Eaguna 

do 

I 

1 384±8 

Bloody Butcher 

do 

1 ! 

405±7 

Iowa Si Iverxnine 

do 

2 

407±5 

China White 

do 

2 

4i3±5 . 

Teosinte: 




China V/hiteX Teosinte . . . 


1 

! 376±4 \ .,0^ 

Teosinte. 

Euchlaena mexicana 

I 

390±ii / 3 3 

Wheat: 




Turkey, C. I. 1571 

Triticum aestivum 

I 

473 ±S 

Kharkov, C. I, 1583 


I 

47S±S 

Kubanka, C. I. 1440 

Triticum durum 

3 

492 ±4 

Galgalos, C. I. 239S 

Triticum aestivum 

I 

496±4 513 

Emmer, C. I. 2951 

Triticum dicoccum 

2 

S 45±7 

Spring Ghirka, C. I. 1517. . 

Triticum aestivum 

2 

55 o ±3 

Marvel Bluestem,C. 1. 3(^2 


2 1 

5 S 9±4 



Oct. IS, 1914 


Water Requirement of Plants 


59 


TABti? XXXIV . — Summary of water -requirement determinations at Akron, Colo., in 
jgil, 1912, and 191^, based on the production of dry matter — Continued 


Water requirement. 

Nmn- 

ber 

of ob- „ 

serva- Of species or 
tious. variety. 


grain crops — continued. 

Barley; 

Hannchen, C. I. 531 Hordeum distichon 

Beardless, C. I. 7x6 Hordeum vulgarc 

Beldi, C. I. 190 do 

White Hull-less, C. I. 595 do 

Buckwheat Fagopyrum fagopyrum. 

Oats: 

Canadian, C. I. 444 Avena sativa 

Swedish ^lect, C. I. 134 do 

Burt, C. I. 293 do 

Sixty-Day, C. I. 165 do 

Rye, spring, C. I. 73 Secale cercalc 

Rice, Honduras, C. I. 1643. • ■ ■ sativa 

Flax, North Dakota, No. 155. . Dinum usitatissimum. .. 


5 '> 2 dh 4 
542 ±3 

556±2 . 

578^13 578 


2 559±8 

3 594±4 

3 6 i 3±3 

2 62 2 ±9 
2 685 ±7 

2 7io±i5 

I 905±25 


Beet, sugar: 

Morrison -grown Klein- 
wanzleben. 

Potato: 

Irish Cobbler 

McCormick 

Crucifers: 

Cabbage, Early Jersey, 
Wakefield, 

Turnip, Purple-top 

Rape 

Cotton, Triumph 

Cucurbits: 

Watermelon, Rocky Ford. . 
CantaUjupc, Rocky Ford. . 
Cucumber, Boston Pickling 

Squash, Hubbard 

Pumpkin, common field . . 
Legumes: 

Cowpea, S. P. I. 29282 

Chick-pea, S. P. I. 24322.. 

Bean, navy 

Bean, Mexican 

Bean, soy, S. P. I. 21755. ■ 
Bean, soy (wild),' S. P. I. 

^25138- 

Uover, sweet, S. P. I. 21216 
Pea, Canada field, S. P. I. 

^30134- 

Pea, Canada field, S. P. I. 
22637. 

Vetch, hairy, S. P. 1 . 34298 
Bean, horse, S. P. I, 25645 , 
Bean, horse, S. P. 1. 15429, 
Vetch, purple, S. P. I. 
18131. 

Clover, red, S. P. I. 34869. 
Clover, crimson, S. P. I. 

33742. 


Beta vulgaris. 


Solanum tuberosum., 
. . . .do 


Brassica oleracea capiLata. 


Brassica rapa 

Brassica naptis 

Ck)ssypium hirsutum. , 


Citrullus vulgaris. . . 

Cucumis melo 

Cucumis sativa 

Cucurbita maxima.. 
Cucurbita pepo 


Vigna sinensis 

Ciccr arietinum. .. . 
Phaseolus vulgaris. 

do 

Glycine hispida. . . 
Glycine soja 


Melilotus alba. . 
Pisum sativum , 


. . . .do 

Vicia villosa 

Vicia faba 

. . . .do 

Vicia atropurpurca, 


Trifolium repens 

Trifolium incamatum. 


397±6 397 


i} <^36 


I 639 ± 3 i I 

1 743±7 J 

2 646 ± I r 646 

I 600 ±15 600 

; 

I 748±8 1 

I 834±i7 I 

I 57ii3 571 

I 665 ±18 663 

I 682 ±4 il g 

I 672 ±9 ;1 ^ 

1 8i 5±25 ij 

2 77 oJ ^5 I 770 

I 775±5 ;1 



6o 


Journal of Agricultural Research 


Vol. in. No. I 


Table XXXIV . — Summary of waier-requiremcnt determinations at Akron, Colo., in 
igzi, 1 Q 12 , and 1913, based on the production of dry matter — Continued 


Plant. 

Botanical name. 

Num- 
ber 
of ob- 
serva- 
tions. 

Water requirement. 

Of species or 
variety. 

^ genus. 

OTHER CROPS — continued. 





hegumes — Continued, I 

Alfalfa, Peruvian, S. P. I. 1 

Medicago sativa 

'Years. 

1 

651 ±12 


30203. 




Alfalfa, Grimm, A. D. I. 

do 

2 

844 ±8 


1^-23-20-52. 

Alfalfa, yellow-flowered. . 

Medicago falcata 

I 

865 ±18 

• 831 

Alfalfa, Grimm, S. P. I. 

Medicago sativa 

2 

963 ±9 


^ 25695- 

Grasses: 




Wheat -grass 

Agropyron cristatum 

I 

705±27 

} S61 

Brume-grass 

Bromus inermis 

I 

I, oi 6±26 

NATIVE PLANTS. 





Tumbleweed 

Amaranth us graecizans. . . . 

1 

277±4 

} =87 

Pigweed 

Amaranthus retroflexus . . . 

2 

297 ±4 

Purslane 

Portulaca oleracea 

I 

292 ± II 

292 

Grass, buffalo 

Bulbilis dactyloides 

1 

3 o 8 ±i 7 

308 

Thistle, Russian 

Salsola pestifer 

I i 

336 ±5 

336 

Grass, buffalo and grama 

fRulbilis dactvloides 

iBouteloua gracilis 

} - 

389±i2 

389 

Cocklebur 

Xanthium commune 

I 1 

432 ±13 

432 

Gum weed 

Grindelia squarrosa 

I : 

60S ± 23 

608 

Sage, mountain 

Artemisia frigida 

I ! 

6i6± j8 

616 

Sunflower (Akron) 

Helianthus petiolaris ' 

I ' 

774±20 

] 

Sunflower (sand hills) 

do ' 

I ■ 

57o±ii 

683 

Sunflower 

Helianthus annuus ' 

I 

705±8 

hamb ’s-quarters 

Chenopodium album 

I 

801 ±41 

801 

Marigold, fetid 

Bnehera p.'ippn.<?,T 

j 

88 1 i 26 

88 1 

Ragweed, western 

Ambrosia artemisifoHa 

I 

g48±(J6 

948 

Wheat-grass, western 

Agropyron Smithii. . , 

I 

I, oj6±29 

I, 076 


The results given in the summary table (Table XXXIV) therefore 
represent the water requirement of the plants for years similar to 1911 
and 1913, when grown in a screened inclosure, which reduces the solar 
radiation to 80 per cent of its normal value. According to measurements 
made with wheat, alfalfa, and cocklebur, the removal of the inclosure 
w^ould increase the water requirement as given in the table by 25 per 
cent. The plants grown outside the inclosure were isolated and freely 
exposed, while plants under held conditions mutually protect and shade 
one another to some extent. Comparison with wheat plants grown in 
pots sunk in trenches indicates that the inclosure measurements, at 
least in the case of wheat, are less than 10 per cent below the water 
requirement of plants exposed under held conditions. 

The measurements in Table XXXIV represent the relative water 
requirement of the different plants tested, subject to the limitations 
imposed by the difference in the growth period of the plants. The 



Oct. 15 , J9I4 


Water Requirement of Plants 


6i 


measurcTnents in 1912 would also indicate that the character of the 
season influences the water requirement of some plants more than 
others. I^or this reason, where the results of two or more years have 
been combined in the table, the probable error has been confined to the 
errors of experiment and does not include the fluctuations in water re- 
quirement due to the season. 

In order to facilitate comparison, the plants have been arranged 
under three main heads: Grain crops, other crops, and native plants. 
Under “Grain crops” are also included certain sorghums and millets 
which are usually grown for forage. Under the heading “Other crops” 
are included principally the legumes, cucurbits, crucifers, sugar beets, 
cotton, and potatoes, as w'ell as some of the introduced grasses. Under 
the heading “Native plants” are listed indigenous species, as well as 
certain introduced species which have become thoroughly established. 

The grain crops fall rather naturally into two sections: Those of low 
water requirement — proso, millet, sorghum, and com — and those of high 
water requirement — wheat, barley, oats, rye, and flax. The plants with 
a comparatively low water requirement are late-maturing crops, which 
make their best growth during the hottest and driest portion of the 
summer. The plants having a comparatively high water requirement 
mature during midsummer and make their best growdh during the earlier, 
cooler period of the year. The range in winter requirement of the first 
group is from 261 for Kursk millet to 468 for Sudan grass, while the 
range in the second group is from 473 for Turkey w heat to 905 for flax. 

Representing the water requirement of proso as i, the water require- 
ment of the grain crops is as follows; Millet, 1.06; sorghum, i.io; corn, 
1.26; teosinte, 1.34; w^heat, 1.76; barley, 1.83; buckwheat, 1.98; oats, 
2.04; rye, 2.34; rice, 2.42; and flax, 3.38, In other words, flax requires 
more than three times as much water and rice more than twice as much 
water as proso and millet in producing a pound of dry matter. 

In the second group sugar beet ranks first, having a water requirement 
almost as low as com. Potato ranks next, follow^ed by crucifers, cucur- 
bits, legumes, and grasses, in order. A wide range is shown in each of 
these families. The groups as a w^hole show a range somew^hat less than 
the grain groups. 

Representing the w^ater requirement of sugar beet as i , the values for 
the “Other crops,” exclusive of the legumes, are as follow's: Cabbage, 
1.36; Irish Cobbler potato, 1.39; watermelon, 1.3 1 ; cantaloupe, 1.57; tur- 
nip, 1.60; cotton, 1.63; cucumber, 1.80; wlieaL-grass, 1.S5; rape, 1.87; 
squash, 1.89; pumpkin, 2.10; and bromc-grass, 2.36. 

The cowpea was the most eflicient of the legumes. Representing its 
water requirement by i, that of the other legumes is as follows: Peruvian 
alfalfa, 1.14; chick-pea, r.i6; soy bean, 1.18; navy bean, 1.20; hairy 
vetch, 1. 21; sweet clover, 1.35; Mexican bean, 1.35; horse bean, 1.36; 
red clover, 1.38; Canada field pea, 1.38; crimson clover, 1.41; wild soy 



62 


Journal oj Agricultural Research 


Vol. III. No. r 


bean, 1.42; select Grimm alfalfa, 1.48; yellow-flowered alfalfa, 1.5 1; 
purple vetch, 1.64; and unselected Grimm alfalfa, 1.69. 

The native plants show a range in water requirement greater even 
than the cultivated crops. Amaranths, buffalo and grama grasses, 
purslane, and Russian thistle have a low water requirement and com- 
pare favorably wth millet and sorghum, while sunflower, fetid marigold, 
western ragweed, and western wheat -grass have a high water requirement 
about equal to that of alfalfa. 

Representing the water requirement of tumbleweed (Amaranthus 
graecizans) as unity, the water requirement of these native plants is as 
follows: Purslane, 1.05; pigweed, 1-07; buffalo grass, i.n; Russian 
thistle, 1. 21; buffalo and grama grasses, 1.40; cocklebur, 1.56; guraweed, 
2.20; mountain sage, 2.22; sunflower, 2,56; narrow-leaved sunflower, 
2.80; lamb’s-quarters, 2.89; fetid marigold, 3.18; western ragweed, 3.42; 
western wheat-grass, 3.89- 

Varieties of the same crop often differ widely in water requirement. 
In the case of barley, the variety having the highest water requirement 
was 8 per cent above the lowest; oats, ii per cent; wheat, 18 per cent; 
proso, 27 per cent; com, 31 per cent; vetch, 35 per cent; alfalfa, 48 per 
cent; sorghum, 60 per cent; and millet, 70 per cent. This wide range 
in water requirement among the varieties of many crops encourages the 
belief that strains may yet be secured which are still more efficient in the 
use of water than those now grown in dry-land regions. 


LITERATURE CITED 


Abbot, C. G. 

igir. The silver disk pyrheliometer. In Sraithsn, Misc. Collect., v, 56, no. 19, 
10 p., I pi. 

and Fowre, F, E. 

1913. Volcanoes and climate. In Smithsn. Misc. Collect., v. 60, no. 29, 24 p., 
3fig' 

Briggs, L- J- 

1913. A mechanical differential telethermograph and some of its applications. 
In Jour. Wash. Acad., Sci., v. 3, no. 2, p. 33-35, i fig. 

and BfiLZ, J- O. 

1910. Dry farming in relation to rainfall and evaporation. U. S. Dept. Agr, Bur. 
Plant Indus. Bui. 188, 71 p., 23 fig., r ph 

1913. Evaporation in the great plains and intermountain districts as influenced 

by the haze of 1912. In Jour. Wash. Acad. Sci., v. 3, no. 14, p. 381-386. 
and Shantz, H. L- 

1913a. The water requirement of plants. I. — Investigations in the Great Plains 
in 1910 and 1911. U. S. Dept. Agr. Bur, Plant Indus. Bui. 284, 49 p., 
2 fig., II pi. 

1913b. The water requirement of plants. II. — A review of the literature. U. S. 
Dept. Agr. Bur. Plant Indus. Bui. 285, 96 p., 6 fig. 

Cbi-UNS, G. N. 

1914. A drought-resisting adaptation in seedlings of Hopi maize. In Jour. Agr. 

Research, v. i, no. 4, p. 293-302, 2 fig., pi. 29-32. 



I9U 


Water Requirement of Plants 


63 


Kimball, H. H. 

igi3a. The effect of tlie atmospheric turbidity of 1912 on solar radiation intensi- 
ties and skylight polarization. In Bui. Mt. Weather Observ., v. 5, 

pt. s- p- 295-312. 1 fig. 

J9i3b. The unusual atmospheric haziness during the latter part of 1912. In Jour. 
Wash. Acad. Sci., v. 3, no. 10, p. 269-273. 

TawES, J. B. 

1850. Experimental investigation into the amount of water given off by plants 
during their growth, especially in relation to the fixation and source of 
their various constituents. In Jour. Hort. Soc. London, v. 5, p. 38-63, 
illus. 

Leather, J. W. 

1910. Water requirements of crops in India. In Mem. Dept. Agr. India, Chem. 

Ser., v. I, no. 8, p. 133-184, pi. 3-19. 

1911. Water requirements of crops in India. — II. In Mem. Dept. Agr. India, 

Chem. Ser., v. i, no. 10, p. 205-281, illus. 

"Student.” 

1908. The probable error of a mean. In Biometrika, v. 6, no. i, p. 1-25. 

Vtnall, H. N., and Ball, C. R. 

1913. Feterita, a new variety of sorghum. In U. S. Dept. Agr. Btir. Plant 
Indus. Circ. 122, p, 25-32. 



PLATE I 

Fig. 1. — General view of the plant inclosure used at Akron, Colo,, showing the pipe 
framework covered with a hail screen, with the board base surmounted by a single 
width of cheesecloth to protect the plants gainst high winds. Photographed on July 
IS, 1912. 

Fig. 2 . — General view inside the inclosure, diowing the arrangement of pots and 
general conditions of growth. Com and sorghums are shown in the foreground, small 
grain in the background. Photographed on July 3, 1912. 

Fig. 3. — General view of the inclosure photographed shortly after the grain in some 
of the pots had been harvested. Photographed on September 4, 191a. 

(64) 








PLATE II 


Fig. I.— Pot planted with sugar beets, showing the wax seal around the plants and 
also the sealed holes where stand was not perfect. 

Fig. 2.— Weighing pots, showing spring balance, weighing support, and general pro- 
cedure. Two men operate the weighing support, one of whom lifts tlie pot by means 
of a windlass, while a third reads the balance and records the weight. By this method 
weighings can be made at the rate of two per minute. 

Fig. ^.--Grindelia squarrosa (gumwecd) at left (pot 164), and Artemisia frigida 
(mountain sage) at right (pot 167), illustrating the growth of native plants used in the 
water-requirement measurements. Photographed on July 29, 1912. Water require- 
ment of Grindelia, 468±i8; of Artemisia, 474^14. 

60300°— 14 5 



PLATE III 

Fig. 1 . — Kubanka wheat (pots i to 6), grown May 9 to September 3, 1912, Photo- 
graphed on July 19, 1912. Water requirement, 394±7. 

Fig. 2.— ’White HulMess barley (pots 103 to 108), grown May 16 to August 12, 1912. 
Photographed on July 19, 1912, Water requirement, 439=1=1. 

Fig. 3. — Kubanka w’heat (pots 12 to 18). Set grown outside of shelter, May 9 to 
August 31, 1912. Photographed on July 26, 1912. Water requirement 507=hi3* 

Fig. 4. — Emnier (pots 61 to 66), gT0^vn May ii to August 12, 1912. Photographed on 
July 19, 1912, Water requirement, 428=1=3. 

Fig, 5 —Swedish Select oats (pots 85 to 90), grown Jlay 17 to August 23, 1912. Pho- 
tographed on July 26, 1912. Water requirement, 423=h5. 

Fig. 6. — Kharkov wheat (pots 37 to 42), grown April 27 to August 28, 1912. Photo- 
graphed on July 29, 1912. Water requirement, 3651^:6. 






PLATK IV 


Fig* I —Northwestern Dent corn (pots 277 to 282), grown June 9 to September 16, 
1Q12. Photographed on September 6, 1912. The lower leaves were picked off as 
they became dry and placed in bags attached to the pots, thus avoiding loss of dry 
matter. Water requirement, 28o±io. 

Fig. 2. — Hopi corn (pots 295 to 300), grown June 12 to September 26, 1912, Pho- 
tographed on September 9, 1912. The lower leaves were picked off as they became 
dry and placed in bags attached to the pots. Water requirement, 285^7. 

Fig, 3.— White durra (pots 235 to 240), grown June 9 to September 26, 1912. Pho- 
tographed on September 6, 1912. The lower leaves w^erc removed as soon as they 
became dry and placed in bags attached to the pots. Water requirement, 255^:3. 

Fig. 4. — Red Amber sorghum (pots 253 to 258), grown June 29 to September 27, 
igu. Photographed on September 7, 1912. Water requirement, 237^4. 

Fig. 5. — Minnesota Amber sorghum (pots 247 to 252), grown June 9 to Scptcm]>er 26, 
1912. Photographed on September 9, 1912. Water requirement, 239±2. 



PLATE V 

Pig. I, Sudan grass (pots 211 to 216). First crop, grown May 28 to July 26, 1912. 
Hiotographed on July 25, 1912. Water requirement, 3i2±3, 

Fig. 2.— Voronezh proso (pots 199 to 204), grown June 5 to August 20, 1912. Pho- 
tographed on July 29, 1912. Water requirement, 2o6±i. 

3- Kursk millet (pots 205 to 210), grown June 9 to August 20, 1912. Pho- 
tographed on July 30, 1912, Water requirement, 187 ±2. 

Fig. 4.— Select Grimm alfalfa (pots 139 to 144), growm in the open, May 24 to July 
27, 1912. Photographed on July 26, 1912. Water requirement, 7453122. 

Fig. 5.— Select Grimm alfalfa (pots 133 to 138). grown in the shelter, May 24 to 
July 26, 1912. Photographed on July 26, 1912. Water requirement, 6oo±i7, 



Plate V 




Plate VI 





PLATK VI 

Fig. r. — Cowpea (pots 151 to 156), grown June 17 to August 26, 1913. Photographed 
on July 26, 1913. Water requirement, 571 ±3. 

Fig. 2. — Hairy vetch (pots 181 to 186), gro^vn May 29 to July 18, 1913. Photographed 
on July 17, 1913* Water requirement, 672^19. 

Fig. 3. — Soy bean (pots 193 to 198), grown June 1 to August 26, 1913. Photographed 
on July 26, 1913. Water requirement, 690^:8. 

Fig. 4. — Cantaloupe (pots 325 to 330), grown June 14 to September 13, 1913, Pho- 
tographed in place on July 26, 1913. Water requirement, 7 78 ±34. 

Fig. 5. — Indian Flint com (pots 253 to 258), gro^vn June 7 to August 27, 1913. 
Photographed on July 26, 1913. Water requirement, 342 ±5. 

Fig, 6. — McCormick potato (pots 121 to 126), grown June 5 to October 4, 1913. 
Photographed on July 26, 1913. Water requirement, 717 in. 



PtATK vir 

Fig^. I, — Triumph cotton in shelter (pots 163 to 168), grown May 29 to September 
16, 1913. Photographed on September 15, 1913. Water requirement, 657±ii. 

Fig, 2. — Boehera papposa, grown July 25 to September 17, 1913. Photographed 
on September 15, 1913. Water requirement, S8i±26. Helianthus petiolaris in back- 
groxmd. 

Fig. 3. — Rice in shelter (pots 157 to 162), growm June 12 to September 16, 1913. 
Photographed on September 15, 1913. Water requirement, 744^17. 

Fig. 4. — General view of the shelter, showing emmer at the left and White Hull -less 
barley at the right. Photographed on July 3, 1912, 

Fig. 5. — General view in the shelter, showing com in the foreground. Photographed 
on September 6, 1912. 






heart-rot of oaks and poplars caused by 
POLYPORUS DRYOPHILUS 


By Georgs G. Hedccock, Pathologist, and W. H. Loetc, Forest Pathologist, Investi- 
gations in Forest Pathology, Bureau of Plant Industry 

INTRODUCTION 

The oaks (Quercus spp.) of the United States are diseased by a number 
of species of fungi which attack the heart wood. Von Schrenk and Spauld- 
ing (1909)^ briefly described some of these diseases and also a piped rot 
of the heart wood of oaks and chestnuts {Castanea dentaia) the cause of 
which was unknown to them. Ini 909, the senior writer found Polyporus 
dryophilus constantly associated with a whitish piped rot of several spe.- 
cies of oaks in the southwestern and western United States. This rot was 
much like that described by Von Schrenk and Spaulding and was identical 
with that of specimens in oak collected by them. Later observations by 
the senior writer established the causal relation of Polyporus dryophilus 
to this piped rot. 

The junior w^riter in 1913 found a second form of piped rot caused by 
Polyporus pUoiae in the heart- wood of the root and basal portion of the 
trunks of oaks and also in chestnuts. This w^as identical with the rot in 
chestnut trees figured and collected by Von Schrenk and Spaulding. 

The oaks of the southwestern and w-estern United States are not used 
to any extent for lumber and timbers and are, as a rule, valuable only for 
fuel. This is due to the rotted condition of the heart wood in the larger 
and older trees. For example, the trunks of the valley oak (Qtcercus 
lobata),^ which attains a large size in the valleys of central California, are 
usually either badly decayed or hollow and are of no value except for the 
poor grade of fuel they furnish. The senior writer in 1909 ascertained 
that Polyporus dryophilus was the chief cause of the deterioration of the 
oaks of the western United States. Meinecke (1914) reports a destruc- 
tive heart-rot of oaks caused by this fungus in California and Nevada, 
and data by him will be dted in the section on the distribution of the 
fungus. In Arizona and New Mexico the oaks are diseased in the heart- 
wood nearly as badly as in California and Oregon, and P. dryophilus is the 
common cause of decay. In these States oaks are usually small and are 
valuable only for fuel. 

In Texas and the adjacent States of Oklahoma and Arkansas the 
piped rot produced by this fungus is very common, and am’ong other 

> Bibliographic citations in parentheses refer to '‘Literature cited, ” p. 77. 

* The nomenclature for trees used in this paper is that of George B, Sud worth ( 1S98). 


Journal of Agricultural Research. 

Dept, of Agriculture, Washington, U. C 


(6S) 


Vol. III. No. I 
Oct. 15, 1914 
G -34 



66 Journal of Agricultural Research voi. iir, no. i 

species the valuable white oak {Quercus alba) is commonly attacked. 
To the east and north the fungus has been found less frequently, but it 
occurs in many sections. 

From observations and estimates Polyporus dryophilus ranks with the 
most common heart-rotting fungi which attack the oaks. In 1912 the 
senior writer found aspens {Populus iremuloides) in Colorado attacked by 
this fungus. It apparently is not commonly found on this host. 

PIPED ROT CAUSED BY POLYPORUS DRYOPHILUS 

The whitish piped rot caused by Polyporus dryophilus has been found 
by the writers to be directly associated with the sporophores of this fungus 
in the following t 5 species of trees : Quercus alba, Q. arizonica, Q, californicaj 
Q. digitaia, 0 . emoryii, Q. ga^nbeln, Q. garrya'ua, Q. marilandica, Q. minor ^ 
Q. prinoideSj Q, priniis, 0 . texana, Q. veluHna, Q. virginianci, and Populv^ 
iremuloides. 

PIPED ROT IN THE WHITE OAK 
MACROSCOPIC CUARACTRRS 

The first indication of the whitisli piped rot in white oak is a discolora- 
tion of the heartwood, which assumes a water-soaked appearance (Pi. VIII, 
fig. 1). This “soak'’ may extend from i to 10 feet beyond the actually 
rotting region where delignification is occurring. When dry, this water- 
soaked heartwood becomes hazel to tawny in color. The next stage of 
the rot is one of delignification, which usually begins alongside of and fol- 
lowing more or less regularly the medullary rays, thus producing a mottled 
appearance of the wood in radial view (Pi. VIII, figs. 2,5, and 6). This 
type of the rot is very common in the medium-sized branches (6 to 12 
inches in diameter) and in the early stages of the disease in the bole of the 
tree. In final stages the diseased wood is firm, has a white, stringy ap- 
pearance (PI. Vni, figs. 3 and 4) and consists of white cellulose strands of 
delignified wood fibers and other wood structures bounded by areas of 
apparently sound but actually slightly diseased and discolored heartwood. 
Cinnamon-brown areas are scattered throughout the oldest rotted wood 
(PI. Vm, fig. 3). These areas are especially common and abundant in the 
vicinity of sporophores and along checks or openings through the sap- 
wood. The rot immediately adjacent to a sporophore is therefore often 
cinnamon brown to russet in color. No cavities large enough to be seen 
by the naked eye are produced by this rot, but much of the white cellulose 
is finally absorbed, leaving minute irregular cavities in the wood. 

MICROSCOPIC CHARACTERS 

Deligmfication usually begins in the wood fibers lying next to the vessels 
in the spring wood and adjacent to the large medullary rays. The sol- 
vents secreted by this fungus apparently are able to delignify all of the 



Oct. 15. J 9 U 


Heart-Roi of Oaks and Poplars 


67 


elements of the wood. All, or only the outer rows, of cells of the large 
medullary rays may be delignified, the middle lamellae dissolved, and the 
completely delignified cell membranes partially absorbed. 

Isolated areas between the large medullary rays may also be delignified. 
The cells of some of the medullary rays and of the wood parenchyma 
often contain starch grains even after the absorption of a portion of the 
inclosing cell walls. A ferruginous substance is also present in many of 
the cells of the small medullary rays, in the lumen of the wood fibers, 
and even in some of the other wood structures. Many of the vessels 
adjacent to each large medullary ray contain hyaline branching hyphie 
0.5 to I /I in diameter. The association of the delignified areas with the 
medullary rays is readily seen in a cross section of the wood where 
delignification is just beginning, but later in the more advanced stages 
of the rot this association is not so evident when the delignification of 
the wood fibers has become general throughout the rotting area. The 
early absorption of portions of the delignified tissue prevents the forma- 
tion of long continuous strands of cellulose fibers, although in a tangential 
view irregular white lines may be seen which consist of fragments of the 
delignified cells (PI. VIII, fig, 5). In very advanced stages of the rot near 
the center of the tree white longitudinal lines are seen in a radial view 
(PI. VIII, fig. 4). These usually consist of remnants of partially absorbed 
cellulose fibers bound together by strands of white mycelium, which 
also fill the vessels and the minute cavities left by the absorption of the 
delignified tissue. 

PIPED ROT IN CHESTNUT 0.\K 

The rot produced by Poly pot us dryophilus in the chestnut oak {Quercus 
prinus) is slightly different from that in white oak. The diseased wood 
is hazel in color, with very narrow concentric zones of ivory-yellow 
cellulose. These zones are adjacent to the large spring vessels of each 
year and consist of the delignified wood fibers of this tissue. The large 
vessels in radial-longitudinal view are seen, even under a hand lens, to be 
filled with cobwebby strands of colorless hyphae. It is in the tissue 
adjacent to such hyphae-fillcd vessels where the delignification is most 
pronounced. 

PIPED ROT IN THE WESTERN OAKS 

The rot caused by Polyporus dryophilus in these oaks differs but little 
from that found in the white oak. The mottled appearance o.f the rot 
in its earlier stages is not so pronounced. In the final stage of the rot, 
after a very large proportion of all the elements is delignified, there is 
hut little apparently sound heartwood. In the older rot in the center 
of the heartwood the white color by far exceeds the brown, of which 
there is very little. 



68 


Journal of Agricultural Research 


Vol. III. No. i 


PIPED ROT IN EUROPEAN OAKS 

Robert Hartig (1878), in his epoch-making work on the true nature 
of the rots of woods, described a whitish heart -rot of the oak, which he 
attributed to Polyporus dryadeus. A careful study of Hartig’s figures, 
and the description of the sporophore which he found associated with 
the white heart-rot so accurately described by him, is sufficient to con- 
vince anyone who is familiar with the true P. dryadeus that Hartig *s 
fungus was not P. dryadeus. It is undoubtedly identical with the 
heart-rotting fungus known in America as P. dryophilus and found by 
the senior author to be associated with a whitish piped rot in oak. 
Through the kindness of Dr. Von Tubeuf the junior writer obtained a 
piece of the original rot (PI. VIII, figs. 7 and 8) which Robert Hartig (1878) 
ascribed to P. dryadeus. A careful study of this specimen showed that 
it is identical in every respect with the rot produced by P. dryophilus 
in the white oak. There is also another European specimen (PI. VIII, 
fig. 9) of this rot in oak in the Laboratory of Forest Pathology, of the 
Department of Agriculture, which has all the characters of the rot pro- 
duced by P. dryophilus. 

CHARACTERS OF PIPED ROT COMMON TO ALL SPECIES OF OAKS 

The rots produced by Polyporus dryophilus in all the species of oak 
examined had the following characters in common: (i) A water-soaked 
discolored area in the first stage (PI. VHI,fig. i); (2)a general association 
of the earlier dclignification with the medullary rays (PI. VIII, figs. 5 
and 6); (3) later a more general delignification of all the wood fibers 
(PI. VIII, fig. 3); (4) the formation of white mycelial longitudinal lines 
(PI. VIII, fig. 4); (5) the presence of cinnamon -brown areas in the older 
rotted wood (PI. VIII, fig. 3). These brown patches, ranging from 2 by 4 
mm. up to 10 by 35 mm. in size, consist of fragments of wood interwoven 
with ferruginous, thick-walled, septate hyphae, which easily break into 
short pieces. The hyphae are about thick, have many short (3 to 8/1) 
branches, and are mixed with various sizes of hyphse down to ipt or less 
in diameter, the smaller of which are hyaline. 

HEART-ROT PRODUCED BY POLYPORUS DRYOPHILUS IN ASPEN 

The description of the heart-rot which follows was made from the 
diseased wood of a dead aspen {Populus trermUoides) bearing the sporo- 
phores of Polyporus dryophilus. 

MACROSCOPIC CHARACTERS 

The general color of the diseased wood varies from a light buff to a 
maize yellow. In a cross section the rotted wood shows alternating 
concentric zones of light buff and ochraceous tawny. The light-colored 
zones consist of the vessels and wood fibers which have been the most 
vigorously attacked by the solvents of the fungus. The ochraceous- 



Oct. IS- ^9^* 


Heart-Rot of Oaks and Poplars 


69 


tawny zones consist of vessels, cells of wood parenchyma, and other 
elements of the wood in the cells of which a ferruginous amorphous 
substance has been deposited. These cells are not as strongly attacked 
by the fungus as are those of the light zones. The rotted wood easily 
splits into concentric layers, the cleavage usually occurring along the 
boundary between the white and dark zones. In a tangential view, 
small, more or less isolated areas of delignified wood fibers may be seen. 
These delignified fibers are most abundant in the older, rotted portion. 
In the vicinity of the sporophores the typical cinnamon-brown areas 
seen in the oak are also present. The rotted wood is soft, almost silky 
to the touch, is very light in weight, and is easily broken into fragments 
between the fingers. 

MICROSCOPIC CHARACTERS 

The vessels in the light-colored zone have very thin walls, owing to 
the action of the fungus; the bordered pits are often eroded until only 
large irregularly shaped holes are left and the middle lamellae of the 
vessels and of the w^ood fibers in this region are dissolved. The \vood 
fibers and some of the adjacent cells are finally delignified and absorbed. 
The delignification occurs most rapidly along the boundary lines between 
the light -colored and dark -colored zones, along which the cleavage com- 
tnonly occurs. The small amount of delignified fibers present and their 
rather rapid absorption prevent the formation of the large areas of white 
cellulose which are so common in the rot produced by this fungus in oak. 
In the zone of cleavage cobwebby masses of white mycelium occur w^hich 
fill the vessels and the small cavities left by the absorption of the wood 
fibers. The medullary rays are readily attacked by the solvents of this 
fungus and usually have completely disappeared by the time the final 
stage of the rot is reached. 


ENTRANCE OF THE ROT IN THE HOST 

Polyporus dryophiliis , so far as known to the writers, gains entrance in 
the wood of the host trees only through w'ounds in which the heart wood 
is exposed. The most common point of entrance is a broken or dead 
Hnib, although in the western and soutlnvestem United States it also 
frequently enters through fire scars and other basal wounds. 

In Arkansas and eastw^ard, where the species of oaks differ from those 
in the West and Southw’est, the rot caused by this fungus is apparently 
confined chiefly to the branches and upper portion of the trunk. This 
may be due to the fact that often there are one or more large dead branches 
in the crown of the tree, while there are very few on the lower part of the 
trunk. The fungus has therefore little or no opportunity to enter the 
bole of the tree below the crown. 

When the fungus enters the stub of a broken limb, it grows downward 
through heart wood of the stub till it enters the trunk, when it spreads 



70 


Journal of Agricultural Research 


Vol. Ill, No. I 


both upward and downward through the heart of the tree. When it 
enters near the base of the tree, it sometimes spreads upward throughout 
the heart of the entire trunk. This occasionally was noted in the white 
oak in Arkansas, and such trees were worthless for lumber. 

In Oklahoma and to the west oaks frequently have large dead branches 
at any point on the trunk of the tree. Through these the fungus may 
enter. The rot therefore is not confined as closely to the upper half of 
the trees as it is in the oaks of Arkansas and to the east. Probably 50 
per cent of the western oaks attacked by this fungus have the rot through- 
out the entire trunk. 

The sporophores of Polyporus dryophilus when growing on oak are 
usually found only on living trees; however, specimens have been col- 
lected growing on the boles and large branches of trees which had been 
cut for at least three years, and in one instance a sporophorc was found 
growing directly on the top of an old oak stump. The fungus apparently 
continues to grow slowly in the infected trees after they have been cut, 
but rarely fruits under such conditions. There is no evidence at hand 
concerning the possibility of infection by P. dryophilus after the death of 
the tree. 

In no instance in Arkansas has the junior writer found this fungus 
entering a tree through fire scars or other wounds on the butt of oaks, 
even where fire scars were common. The rot always originated at some 
point above the base of the tree, and if a tree was found in which the rot 
had reached the collar of the tree it came from above and not from below. 
All of the sporophores of this fungus found on specimens of Populus were 
growing on dead or dying trees. In this case the fungus is able to fruit 
abundantly on both living and dead trees. 

This fungus on Populus seems to be truly parasitic, to some extent at 
least. It attacks the trunks of the trees chiefly, entering the heartwood 
through dead limbs after they are broken off. The trees die by either 
breaking off or in some cases apparently from the direct effect of the fun- 
gus, which attacks the sapwood when the disease becomes far advanced. 

Several instances were found in oak where the fungus had apparently 
penetrated and killed small areas of the sapwood and formed its sporo- 
phores at these points. 

No positive evidence was found indicative of the age of the fungus in 
either oaks or poplars or of its rate of growth in the infected tree. Appar- 
ently trees of all ages are susceptible to this rot, provided the branches 
are old enough to have formed heartwood. 

SPOROPHORE OP POEYPORUS DRYOPHILUS 

Polyporus dryophilus has a hard, granular, sand stone- like core, a 
character that is unique and not possessed by any other polypore known 
to the writers. The sporophore of this plant, represented by numerous 
specimens collected by the writers in various portions of the United 



Oct. IS. 1914 


Heart-Rot of Oaks and Poplars 


71 


States, in every instance shows this hard granular core (PI. IX, figs. 2 
and 4) exactly as figured and described by Hartig (1878) in case of his 
p, dryadeus. This core extends back some distance into the tree in 
oaks; it is usually irregularly cylindrical while in the tree, but on its 
emergence from the tree it swells into a tuberous or spheroid mass and 
finally occupies the central and rear part of the sporophore (Pis. IX, fig. 2, 
and X, fig- 6)- If the sporophore is formed from a large branch hole, 
it is usually of the applanate type, with a small core, but when the sporo- 
phore forms directly on the body of the tree, as it usually does, the shape 
is tuberous, unguliform, or even subglobular (PI. IX, figs. 2 and 4), with 
the bulk of the sporophore composed of hard, granular core. This core 
usually has white mycelial strands (PI. IX, fig. 4). The sporophore of 
P. dryophilus, therefore, has normally three distinct kinds of structures 
(PI. X, fig. 4): (i) The hard, granular core; (2) the fibrous layer which 
surrounds this core except at the rear; (3) the layer of tubes on the lower 
surface. Specimens are often found, however, especially from the 
western part of the United States, in which this fibrous layer may be 
entirely absent between the tubes and the granular core (PI. IX, fig. 4). 

Polyporus dryophilus is known in Europe under at least five different 
names: Polyporus fiilvus Fries, P. jriesii Bresadola, and P. corruscans 
Fries for the form on oak, and P, Tidpimis Fries and P. rheades Persoon 
for the form on poplar. The identity of P. dryophilus with the P. cor- 
ruscayis Fries (PI. X, fig. 4) and with P. rheades Persoon is based on the 
specimens of these plants found in the Lloyd Herbarium at Cincinnati, 
Ohio. If these specimens are correctly determined, then the American 
plant is identical with the European plants named above. Authentic 
specimens of the form of P. dryophilus {oui:id on species of Populus w^ere 
seen by the junior writer at the Xcw York Botanical Gardens in collec- 
tions from Finland and Sweden and also from Maine, In the Lloyd Her- 
barium at Cincinnati, Ohio, are collections under the name of P. rfu'ades 
on Populus trcmida from Sweden (PI. X, fig. 3) and Denmark, and a 
collection from Austria on Querciis ilex. In the Cry ptogainic Herbarium of 
Harv^ard University there is a collection on Pop^dus Michx. 

from New Hampshire, while in the Laboratory of Forest Pathology there 
is a fine collection on Populus trcmul&idcs Michx. (PI. X, figs, i, 2, and 5) 
from near Steamboat Springs, Colo. 

This fungus on Populus agrees in all essential characters with the form 
of Polyporus dryophilus found on oak. The sporophores are,^ however, 
somewhat smaller than those usually found on oak and approach the 
applanate type (PI. X, figs. 1 and 2). The hard granular core is always 
present, but is formed between the sapwood and bark (PI. X, fig. 4), as 
the fungus is able to rot the sapwood, as well as the heart of this host. It 
therefore does not have to depend on brancli holes or other openings 
through the sapwood in order to form its sporophores as it does in the 
oak. 



72 


Vol. Ill, No. I 


Journal oj Agricultural Research 


DESCRIPTION OK THE SPOROPHORE OK POLYPORUS DRYOPHILUS 

Pileus thick, unequal, smooth to irregular nodulose, often convex below, ungulifortn 
(PI. IX, fig. 5), subglobose (PI. IX, fig. i) or even applanate (PI. X, fig. i), simple or 
rarely subimbricate (PI. X, figs. 2 and 5), rigid, 4 to 22 cm. broad by 3 to 13 cm. wide 
(measured from front to rear of sporophore) by 2.5 to 21 cm. thick (measured from pore 
surface to top of sporophore) ; surface at first densely tomentose, becoming scabrous to 
smooth with age ; tomentum rather stiff, deciduous, short, maize yellow to ferruginous; 
surface of weathered sporophores after the tomentum has partially disappeared, ronate, 
zones several, narrow, extending entirely around the pileus near its margin (PI. IX, 
fig. 3) ; margin in immature specimens thick, usually obtuse (Pis. IX, figs, i and 5, and 
X, figs. I and 2), concolorous or slightly pallid, entire or undulate; context dual, con- 
sisting of a hard granular core, surrounded except in the rear by a thin fibrous layer; 
core subglobose to pulvinate, 3 to 10 cm. thick, ferruginous to cinnamon brown, gran- 
ular, often with white mycelial strands ramifying through it (PI. IX, fig. 2); fibrous 
layer on upper surface of core a mere pellicle about 0.5 mm. thick, expanding in mature 
specimens into a border (PI. IX, fig. 4) i to 3 cm. wide and 5 to 15 mm. thick; fibrous 
layer between tubes and core thin, i to 15 mm,, usually not over 6 to 8 mm., fibrous 
layer zonate, concolorous; tubes slender, concolorous or slightly paler than core in 
some specimens, rather fragile in age, 5 mm. to 3.5 cm. long, ^lortcr near margin of 
sporophore, usually about i cm. long; mouths regular when young, but becoming 
somewhat irregular and angular at maturity (Pis. IX, fig. 6, and X, fig. 8), two or three to 
a mm., glistening, grayish when young, becoming hazel to russet witli age, edges thin; 
spores broadly oval, smooth, ferruginous. 4.8 to 8 by 3.4 to 6.4H, average size 6.54 by 
4,85/^ when on oak (PI. IX, fig. 6), 4.8 to 6.4 by 3.4 to 5.6ft, average size 5.82 by 4.05« 
when on poplar (PI. X, fig. S); cystidia none; hyphse ferruginous, 4 to 6 ;j. The 
sporophores found on oak in .Yrkansas and in the eastern portion of the United States 
often have shorter tubes (PI. IX, fig. 4), slightly smaller spores, and a more applanate 
pileus than tliose found in the Western States (PI. IX, fig. 2). 

DISTRIBUTION OF POLYPORUS DRYOPHILUS 

The rot caused by Polyporus dryophilus is very widely distributed in 
the United vStates, having been found in 23 States; Arizona, Arkansas, 
California, Colorado, Illinois, Kansas, Louisiana, Maine, .Maryland, Mis- 
sissippi, Missouri, Nebraska, New Hampshire, Netv !\Iexico, New York, 
North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Tennessee, 
Texas, and Wisconsin. Authentic specimens of the fungus have also 
been examined from the following foreign countries: Austria, Denmark, 
Finland, France, Germany, and Sweden. The sporophores of the fungus 
are frequent and the rot caused by the fungus is exceedingly common in 
New Mexico, Arizona, and California. 

DISTRIBl TIUX IN EI K<>PE 

Polyporus dryophilus is kno\m to occur in Europe as follows, the junior writer 
having examined authentic specimens: 

Germ.\xy (?}: 

On Quercus sp. (F. P, 12404^. 

1 “K. P.”=Forcst-Pathnloi;y Inve^tit'ations number. 



Oct. IS, 19*4 


73 


Heart-Rot of Oaks and Poplars 


Germanv: 

On Quercus sp. — Robert Hartig (from Herb. Von Tubeuf); Pfeiffer (Herb, 
y. Bot. Card.), part of the type specimen for Polyporus friesii; Berlin, Lloyd 
(Herb. Lloyd). 

Austria: 

On Quercus ifej:.-~Travnik, Rev. E. Brandis (No. 08S64, Herb. Lloyd). 

Denmark: 

On Populus (?) sp.— J. Lind (No. 06339, Herb. Lloyd). 

Finland: 

On Populus sp. — Murtiala, Sept., 1882 (No. 5724, Herb. N. Y. Bot. Card.). 
Sweden: 

On Qxtercus ro&wr.— Stockholm, Romell, Oct., 1903 (Herb. N. Y. Bot. Card,), and 
a second specimen, collector irnknowm (Herb. N. Y. Bot. Card.). 

On Quercus sp. — Upsala, Lloyd (No. 08936, Herb. Lloyd); Stockholm, Romell (No. 
08936, Herb. Lloyd). 

On Populus Stockholm, Romell. June 25, 1905 (Herb. N. Y. Bot. Card.), 

and a second specimen, Murrill (Herb. N. Y. Bot. Card.); Stockholm, Hagelund 
(No. 08985, Herb. Lloyd). 

On Populus sp, — Hagelund (No. 09375, Herb. Lloyd); Stockholm, Romell (No. 
08414, Herb. Lloyd). 

France: 

On Phius (?) sp.— Fontainebleau, P. Hariot (No. 08880, Herb. Lloyd); this speci- 
men from France was reported as .on pine, and has sjxjres similar in size and shape to 
those grow ing on species of Populus and a sporophorc much like those found on species 
of Quercus. 

DISTRIBUTION IN UNITED ST.ATKS 

Polyporus dryophilus has been reported from and collected in the various States of 
this country as follows: 

Maine: 

On Populus iremuhides , — Piscataquis Co., Murrill, in 1905 (Herb. No. 1901, N, Y. 

Rot. Gard,}. 

On Beiula (?) sp. — Near Moosehead Lake, Von Schrenk, in 1899 (Herb. N. Y, 
Rot. Card.). 

Xew HAJfPSHIRE: 

On Populus grandidentaia. — Chocorua, Karlow (?), in 1904 (Herb. W. G. Farlow). 
New York: 

On Onrrrnr alba . — Bronx Park, Murrill, in 1908 (F. P. 1416). 

Pennsylvania: 

On Quercus (?) sp. — Kittanning, vSumstine 32 (Herb. N. Y. Bot. Gard.). 

Maryland: 

On Quercus alba, Q. cocctnea, and O. minor. — Takoma Park, Hedgcock, in 1910. 
Omo: 

On Quercus (?) sp. — M. A. Curtis, "Ex. Berkeley" (Herb, \V. G. I'arlow); Preston 
(?), A. P. Morgan, in 1887 (Herb. N. Y. Bot. Gard.); Preston, A. P. Morg.an (0598); 
and Akron, C. D. Smith (07556, Herb. Lloyd). 

Virginia: 

On Quercus Elkins, Long, in 1913 (F. P. 12418). 

On Quercus (?) sp. — Falls Church, Luttrell, in 1902 (Herb. N. Y. Bot. Gard.). 
North Carolina: 

On Quercus pri nus. — Brim, Long. 

Quercus veluiina. — Jonesboro, P. L. Buttrick, in 1913 (F, P, 15045). 



74 


Journal of Agricultural Research 


Vol. HI. No. 


TennBSS^K: 

On Quercus alba and Q. velutina. — Roan Mountain^ Hedgcock, in 1913. 
Mississippi: 

On Q%iercus lyraia. — Sand Point, H^dgcock, in 1908. 

Louisiana: 

On Quercus lyrata, Q. Tnarilandica, Q, mickauxii, and Q. phellos, — Near Bogalusa, 
Hedgcock, in 1908. 

Missouri: 

On Qucrcus alba. — Mountain Grove, Hedgcock. 

On Querctis imbricaria. — Near St. Louis, J, N. Guadfei<ter (No. 1214, Herb. Mo, 
Bot. Card.). 

On Quercus marilandka, — Steelville, Spauuding; Mountain Grove, Hedgcock. 

On Quercus minor. — Webster Groves, A. H. Graves, in 1909 (F. P. 1617). 

On Quercus palustris. — Mountain Grove, Hedgcock. 

Illinois: 

On Quercus alba. — Near Plymouth, Hedgcock, October, 1909. 

Wisconsin: 

On Populus sp. — Oakfield, in 1903 (Herb. Univ. Wise.). 

On Quercus macrocar pa. — Rockton, L. H. Pammel, in t 886 (Herb. N. Y. Bot. 
Card.). 

Nebraska: 

On Quercus macrocarpa. — Near Nelson, Hedgcock, in 1911. 

Oklahoma: 

On Quercus alba. — Cache, Long, in 1912 (F. P. 12407). 

On Quercus marilandica. — Cache, Long, in 1912 (F. P. 12420). 

On Quercus minor. — Cache, Long, in 1912 (F, P. 12408, 12416, 12419, 12421). 

On Quercus prinoides. — Cache, Long, in 1912 (F. P. 12414). 

Arkansas: 

On Quercus alba. — Treat (F. P. 12102), Casteel (Ozark National Forest; F. P. 
12137, 12140, 12142, 12154, 12219, 12243, 12263, 12268, 12296, 12402, 12403, 12405, 
12406, 12409, 1 241 3, 12425); Bigfiat (F. P. 12158, 12156, 12160), Long, in 1912 : Womble 
(F. P. 12413), Cedar Glades (F. P. 12422), Long, in 1913; Fayetteville and Farmington, 
Hedgcock, in 1906. 

On Quercus digila fa. — Casteel, Long, in 1912 (F. P, 12272). 

On Quercus minor. — Whiterock, Long, in 1912 (F. P. 12240). 

On Qwreus iexana. — Mountain View, Long, in 1912 (F. P. 12415). 

On Quercus velutina. — Casteel, Long, in 1912 (F. P. 12410). 

Texas : 

On Quercus marilandica. — Near Boeme, Hedgcock, in 1909 (F. P. 760). 

On Quercus minor. — Austin (F. P. 12424) and Denton (F. P, 12423), Long in 1912. 
On Quercus nigra. — Near Houston, Hedgcock, in 1909. 

On Quercus phellos. — Near Houston and near Boeme, Hedgcock, in 1909. 

On Quercus iexana. — Near Houston and near Boeme, Hedgcock, in 1909 (F. P, 762). 
On Quercus velutina. — Near Boeme, Hedgcock, in 1909. 

On Quercus virginiana. — Near Houston and near Boeme, Hedgcock, in 1909 (F. P. 
320). 

Colorado : 

On Popultts iremulotdes. — Steamboat Springs, Hedgcock, in 1912 (F. P. 3894). 

On Quercus gambelU. — Square Top Moimtain (San Juan National Forest ; F. P. 9229): 
near Mancos (Montezuma National Forest) ; southeast of Delta (Uncompahgre National 
Forest); Hedgcock, in 1912. 

New Mexico: 

On Quercus onsontco. —Pecos, Long, in 1913 (F. P. 12412). 

On Quercus emoryii, — Mogollon Mountains Hedgcock, in 1911. 



Oct. 15 . >9^4 


Heart-Rot of Oaks and Poplars 


75 


On Quercus gatnbelii . — Sandia Mountams (Manzano National Forest), Hedgcock, in 
qo 6(F- F. 136, 230): in 1908 (F. P. 270, SSI-SS3, 55^); near Pinos Altos (Gila National 
Hedgcock, in 1909 (F. P, 811, 812); in Alamo National Forest, L. I<, Jan^s, 
(F P. 1142); MogoUon Mountams, Bear Creek Canyon, and Trout Creek (Gila 
^onal Forest), Hedgcock and Lotro, in 1911 (F. P. 9837): Cloudcroft, Long, in 
(F. P. 12015); P®C 6 s, Long, in 1912 (F. P. 12426). 

Qwrcus oblongifolia.—Neat MogoUon, Hbdgcock, in 1911. 

Arizona : 

On Quercus arizonica. — ChiricahuaMountains, H. D. BuKRALi«,in 1908; nearSedona 
(Coconino National Forest), Hbdgcock, in 1910; Santa Catalina Mountains, Hbog- 
cocK, in 1911- 

On Qwrcus chrysolepis,—SedonA, Hedgcock, in 1910. 

On Quercus emoryii. — Chiricahua Mountains, Bukrabi,, in 1908; Groom Creek and 
Crown King (Prescott National Forest), Hbdgcock, in 1 9 10; Santa Catalina Mountains, 
Hedgcock, in 1911. 

On Quercus gamheliu—^iwim Creek (F. P. 4557), Crown King(F. P. 4877) » Sedona 
(F. P. 4941 )» Flagstaff, Hbdgcock, in 1910; Santa Catalina Mountains, Hbdg- 
cock and Long, in 1911 (F. P. 9801). 

On Quercus Ay/?o/«tca.— Near Pinos Altos, Hedgcock, in 1909. 

On Quercus ohlongifolia. — Groom Creek and Crown King (F. P. 4876) and near 
Sedona, Hbdgcock, in 1911; Santa Catalina Mountains, Hbdgcock, in 1911. 

On Quercus toumeyi. — Santa Catalina Mountains, Hbdgcock, in 1911. 

California: 

On Quercus calif ornica. — Scott River Valley (Klamath National Forest), Hedgcock, 
in 1909 (F. P. 1886); near Mirror Lake (Yosemite Park), Clarks (Plumas National 
Forest), North Fork, and O^Neals (Sierra National Forest), MbinBCkB, in 1910: near 
El Portal and Yosemite (Yosemite Park), Hbdgcock and Meineckb, in 1910 (F. P. 
4794); near Kennett, Hbdgcock and Meinbckb, in 1911 (F. P. 9649)- 
On Quercus chrysolepis.—E\ Portal and Yosemite, Hedgcock and Meineckb, in 1910; 
North Fork (Sierra National Forest), Meineckb, in 1910. 

On Quercus garryana. — Scotts River and Mount Marble (Klamath National Forest), 
Hedgcock, in 1910 (F. P. 1847), 

On Quercus lobaia. — Stanford University, C. F. Baker, in 1902 (Herb. Univ. of Wis- 
consin); near Chico, Hedgcock, in 1909; Dobe and Italian Bar (Sierra National 
Forest), Mbinkcke, in 1910. 

On Quercus wislizeni. — El Portal, Yosemite, and near Raymond, Hedgcock, in 
1910: near Kennett, Hedgcock, in 1911. 

On Quercus sp. — Crane Valley (Sierra National Forest), and El Portal, MbinEcke, in 
1910. 

Oregon ; 

On Quercus garryana. — Near Mount Hood (Oregon National Forest) and Rogue River 
Valley, Siskyou National Forest), Hbdgcock, in 1909 (F. P. 1717); near Medford, 
Hbdgcock, in 1911 (F. P. 9611). 

On Quercus calif ornica. — ^Rogue River Valley, Hedgcock, in 1909. 


From the foregoing data the following trees are attacked by the disease 
caused by Polyporus dryophilus: Quercus alhOf Q. arizonica, Q. calif ornica ^ 
Q. chrysolepis^ Q. coccineaj Q. digitata, Q. emoryii, Q. gambelii, Q. garryana ^ 
hypoleuca, Q. imbricaria, Q. ilex, Q. lohata, Q. lyrata, Q. macrocarpa, 
Q. marilandica, Q. mickauxii, Q. minor, Q, nigra, Q. ohlongifolia, Q. paius- 
tris, Q, phellos, Q. prinoides, Q. prinus, Q. robur, Q. texana, Q. velutina, 
Q. virginiana, and Q. uisHzeni; Popuius grandideniata, P. tremxda, and 
^ . tremuloides; Betula ( ?) sp. , and Pinus ( ?) sp. 



Journal of Agricultural Research 


Vol. Ill, No. t 


76 


CONTROL OF THE PIPED ROT OF POLYPORUS DRYOPHILUS 

The piped rot caused by Polyport^ dryophilus is one of several impor- 
tant heart-rots of oaks in the United States. Suggestions made for 
its control will apply more or less to all of these. So long as oak trees 
are allowed to stand long past maturity in our wood lots and forests, 
heart-rots will continue to be common. The practice of leaving uncut 
in a lumbered area all the badly diseased trees, especially those with 
heart-rot, is radically wrong from the standpoint of proper forest sani- 
tation, for this practice enables heart-rotting fungi to maintain them- 
selves in the forest while the new generation of trees slowly develops and 
attains the age at w^hich they form heartwood and thus become suscep- 
tible to the attacks of heart-rotting fungi. Trees diseased with heart- 
rot ought not to be left for seed trees wherever it is possible to leave 
healthy ones for this purpose. In hardwood forests it is often not neces- 
sary to leave seed trees, owing to the abundant sprout production, and 
the presence of young trees intermingled among the more mature ones. 

Trees in the wood lot should be inspected annually, and all trees evi- 
dently rotted at the heart should be removed. If the trunk of a tree 
diseased with heart-rot is struck with an axe, it does not ring with a 
clear sound. The presence of the fruiting body of Polyporus dryophilus 
on a tree also is e\ddence of the presence of the piped rot and of the 
necessity of removing the tree. Sporophores on trees should be removed 
whenever found. 

In large forested areas it is not possible to personally inspect the trees 
every year nor to search the forests annually for sporophores, although 
the present prices of good white-oak lumber nearly justify the expense 
necessary in a system of careful forest sanitation. It will certainly pay 
in lumbering tracts of oak and other valuable hardwoods to cut out all 
unsound or diseased trees, remove the parts that can be used, and bum 
the remainder. Many trees under the present methods of lumbering 
are left standing because they are decayed in the trunk near the butt. 
If cut down, these trees would be found to contain enough lumber to 
pay for the cost of operation. Such a procedure will lead to a better 
and closer utilization of our gradually decreasing supply of hardwood 
lumber, especially of white oak. 

The destruction of all trees that are rotted in the heart in timber sales 
will be a step far in the direction of control for these diseases of timber. 
A new forest grown on areas lumbered with due regard to sanitation 
will be certain to be nearly free from heart-rot. 



77 


Oct. 15. Heart-Rot of Oaks and Poplars 

LITERATURE CITED 

Robert. 

1878. Die Zersetztitigserschein ungen des Holzes der Nadelholzbiiume und der 
Eiche ... p. 124-128, pi. 17. Berlin. 

MEINECKE, E. P. M. 

1914. Forest Tree Diseases Common in California and Nevada. A Manual for 
Field Use. p. 48-49. Washington, D. C. Pub. by U. vS. Dept. Agr., 
Forest Service. 

ScHRENK, Hermann von, and Spaulding, Perley. 

1909. Diseases of deciduous forest trees. U. S. Dept. Agr., Bur. Plant Indas. 
Bui. i 49> P- 39-40, pi. 5, fig. 1-2. 

Sue worth, G. B. 

1898. Check list of the forest trees of the United States, their names and ranges. 
U. S. Dept. Agr., Bur. Forestry, Bui. 17, 144 p. 



PLATE Via 

Fig. I. — Querctts alba: Crescent-shaped "soak," the initial stage of the piped rot 
produced by Polyporiis dryophilus; from Arkansas. 

Fig. 2. — Quercus alba: A radial view of the rot in a limb, showing delignification; 
from Arkansas. 

Fig. 3. — Quercus oblongifolia: A radial view of rot, showing delignification; from 
Arizona. 

Fig. 4. — Quercus alba: A final stage of the rot, radial view, with more complete 
delignification; from Arkansas. 

Fig. 5- — Quercus alba: A tangential view of the rot, showing delignification in 
pockets; from Arkansas. 

Fig. 6. — Quercus alba: An end view showing a cross section from the same tree as 
the preceding; from Arkansas. 

Fig. 7. — Quercus sp.: A section of oak from Von Tubeuf, sent to the junior writer 
as a specimen of the rot caused by Polyporus dryadeus in Europe. 

Fig. 8. — Quercus sp. : The reverse side of the specimen shown in the preceding. 

Fig- 9. — Quercus sp. : A section of oak from Europe, obtained by Von Schrenk, with 
a piped rot similar to that of Polyportis dryophilus. 

(78) 



Hi^nrt-Rotof Oaks and Popla 


Plate VIII 





Vf.l. ill. N'-). 1 



PLATE IX 

Fig. r. — A spojophore of Polyporus dryopkilus, tuberous form on Quercus gambeiii’, 
from Arizona. 

Fig. 2. — Sectional view of a sporophore of PolyportLs dryophilus on Quercus gamhelii^ 
showing the hard granular core with whitish mycelial strands; also the pore layer; 
from New Mexico. 

Fig. 3.^ — A sporophore of Polyporus dryophilus on Quercus calif ornica, lowing the 
upper surface with a faint zonation; from California. 

Fig. 4. — A section through a sporophore of Polyporus dryophilus on Quercus garryana, 
showing the structure of the hard granular core; from California. 

Fig. 5. — A front view, showing the margin of the same sporophore as in figure 3, 
representing the ungulate form. 

Fig. 6. — A view of the pore surface of an applanate sporophore of Poiyporus dryophi- 
lus on Quercus alba; from .Arkansas. 



PLATE X 

Pig. I. — A spofophore of Polyporus dryophilus, front view showing the margin, on 
Populus irevtuloides; from Colorado. 

Fig. 2.— A second sporophore from the same tree as figure i. showing an imbricated 

3.— A view of the upper surface of a sporophore of Polyporus rheades on Populus 
iremula; from Stockholm, Sweden. 

Fig. 4.— A sectional view of a sporophore of Polyporus corruscans on Quercus; from 
Upsala, Sweden. 

pig_ — A. side view of an imbricate sporophore of Polyporus dryophilus, applanate 
form on Populus tremuloidesi from Colorado. 

pig^ 5 , — X sectional view of the same sporophore as in the preceding figure, showing 
the hard granular core and whitish mycelial strands. 

Fig. 7.— A view of the upper surface of an applanate sporophore of Polyporus 
dryophilus on ^rc«J aWa; from Arkansas. 

pig_ 8 —The pore surface of a sporophore of Polyporus dryophilus on Populus tremu- 
hides; from Colorado. 












PRELIMINARY AND MINOR PAPERS 


decomposition of soil carbonates 

By W, H. MacInTirE, 

Soil Chemist, Tennessee Agricultural Experiment Station 

Investigations recently conducted at the University of Tennessee 
Agricultural Experiment Station have led to the discovery that the 
composition of soils is such as to make inhibitory any long-continued 
occurrence therein of magnesium carbonate, and the conclusion has been 
drawn that magnesium carbonate does not exist as a solid mineral in 
our humid soils. 

The research has demonstrated that the affinity of magnesia for silica 
s such that soils long since alkaline from excessive treatments of calciutn 
carbonate are able to dissipate the CO2 of magnesium carbonate under 
sterile, moist conditions. It has been further demonstrated that the 
affinity of magnesia for silica is so great that precipitated magnesium 
carbonate is extensively decomposed by pure SiOj and also by the closely 
allied compound titanium oxid, which occurs almost universally to an 
appreciable extent in soils. 

Analyses to determine residual carbonates at the end of one year 
established the fact that precipitated magnesium carbonate in amounts 
chemically equivalent to 16,070 pounds of CaCOg per acre in excess of 
the quantity indicated by the Veitch method as necessary to correct 
acidity had been entirely decomposed by each of three distinct types of 
unleached soil. A loam, a sandy loam, and a silty loam were used in the 
study. In substantiating the work the loam soil was subjected to eight 
check treatments in field rim experiments. In each of these eight 
instances precipitated MgCOg equivalent to over 15 tons of a good grade 
of limestone per 2,000,000 pounds of soil had entirely disappeared at the 
end of eight weeks, when the first analyses w^ere made for residual car- 
bonates. No drainage took place during this 8- week interval. 

Comparisons between residual carbonates from limestone and dolo- 
mite treatments showed at the end of 9 months' exposure to weather 
22,000 pounds of CaCOg per 2,000,000 pounds of soil for the limestone 
treatment as compared to 1 1 ,000 pounds of CaCOg as a residue from the 
dolomite. 

The investigations have also determined that the absence of carbo- 
nates subsequent to applications of magnesium oxid has been erro- 
neously attributed to persistent causticity of the magnesia, which is 
shown to be very readily converted to the carbonate, while this in turn 
is decomposed by siliceous substances. 

The use of CaCOg as a check has shown that the affinity of lime for 
silica is far greater than has been supposed, and the work has demon- 
strated that the lime-silica reaction in soils is an important factor in the 
conservation of lime applied in practice. While the lime-silica reaction 

Journal of ACTicultural Research. Vol. HI. No i 

Dept, of Agriculture, WashingtoD, D. C. Oct. 1$, 1914 

Teuti.— t 


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8 o 


Journal of Agricultural Research 


Vol. ni. No. I 


does not approach the magnesia-silica reaction in rapidity, it is sho^ 
by field data that the lime-silica reaction continues long after the attain- 
ing of alkalinity and that the reaction is extensive. 

Toxicity due to excessive treatments of magne^um carbonate after 
its conversion to silicates was demonstrated by plant growth. 

The progress of the work of the writer and associates is reported in 
detail in Tennessee Experiment Station Bulletin 107. 



A FUNGOUS DISEASE OF HEMP 


BvVkraK. Charles, Assistant Mycologist, and Anna E. Jenkins, Scientijic Assistant, 
of Pathological Collections and Inspection Work, Bureau of Plant Industry 

In September, 1913, the attention of the Office of Pathological Col- 
lections and Inspection Work was called to a fungous disease which had 
attacked a variety of hemp {Cannabis saliva) grown for experimental 
purposes by Mr. L. H. Dewey, Botanist in Charge of Fiber-Plant Investi- 
gations. Although the disease did not make its appearance until the 
plants were almost full grown, it was very rapid in its action, only about 
t\vo weeks having elapsed between the time that the disease was first 
noted and the death of many of the plants. One of the early symptoms 
of the disease was the wilting and drooping of the leaves. The foliage 
turned brown and finally died, but remained attached to the plant longer 
than in the normal condition. In nearly all instances the fungus first 
attacked the outer ends of some of the upper, though rarely the highest,' 
branches of the plant. In some cases the branches above and below the 
diseased area remained uninjured for some time. It was observed that 
the disease spread more above than below, but that the affection of the 
plant became general in about two weeks. Although the disease ap- 
peared to attack the outer ends of the branches first, the main stem below 
the base of the diseased branch became bleached and afterwards dark- 
ened by the formation of the perithecia of the fungus (PI. XI ) } 

The hemp was grown from seed originally introduced from China, 
having been grown for experimental purposes during a period of 10 years. 
Its cultivation had been generally successful, and until the season of 1913 
no difficulty had been experienced from fungus attack. 

All of the plants in the plots in which the disease was most serious were 
from the seed of one single selected plant, the third best of the crop of 
1912. This plant showed no evidence of disease and was remarkable 
for its purple -colored foliage. Selections had been continuous for 10 
generations without any admixture of other strains. Three or four 
plants of this plot which were especially precocious were marked as soon 
as it was obser\"ed that they were pistillate, and each one of these plants 
was attacked by the disease. So general was tlie attack that among the 
135 pistillate plants of this plot 128 were destroyed by the fungus, 
representing a loss of about 95 per cent of this plot. Later the disease 
appeared in a larger plot of 320 and in less than four weeks 66 ^ per cent 
of the plants had been attacked. 

A microscopic examination of the first diseased material collected on 
September 12, 1913, revealed the presence of small, black pycnidia, 
containing minute, hyaline spores on branched coni diop ho res. These 
characters, together with the absence of stroma, placed the fungus in the 
genus Dendrophoina. (Fig. i, E and F.) This appears to be the first 
occurrence of the fungus in America. A second examination of the dis- 
eased hemp about three weeks later show^ed pycnidia containing spores 

^Most of the field observBLtons were made by Mr. L. H. Dewey, who mentions the occurrence of this 
disease in an article entitled “Hemu” in the Yearbook, U. S. Dept- of Agriculture, for 191J, p. s83-346, fig. 
X 7 - 2 I, pi. 40-46. 1914. 


^mal of Agricultural Research, 

Uept, of Agricidture, Washington, D. C. 


(81) 


Vol. ni. No. I 
Oct. 15, 1914 

G-i3 




82 


Journal of Agricultural Research 


Vol. lU, No. I 


characteristic of the genus Macrophotna (fig. i, D). At the same date 
an immature ascomycete was observed on material which had been 
allowed to remain on the ground. The final collection on November 3 
showed an ascomycetous fungus present in large amounts on the hemp 
which had been spread for dewretting, while the two other spore forms 
were absent, or present only in negligible amounts, having matured before 
the development of the ascospores. The asd were borne in perithecia 
similar in appearance to the pycnidia of the two other forms (fig. i, B), 



Fig. I. — ^Microscopic characters of the hemp fungus Boiryosphacria marconii. A, Sketch of a section of 
stroma from culture, showing develooiog perithecia: a, microconidial stage. A, ascosporic stage, X S40. B, 
An asms with ascosixires, X 840. C, Ascospores, X 840. D, Macroocmidia, X 840. E, Couidiophorcs of 
the Uendiuphoma stage. X 1920. F, Microconidia, X 1930. (Drawing by J, Marion Shull.) 


The spores were hyaline to slightly colored, nonseptate, and fusoid 
(fig. I, C). A probable connection between these three forms suggested 
itself to the authors, and cultures were started to prove, if possible, that 
these stages are different phases in the life history of one fungus. The 
spores of the Dendrophoma form are designated as microconidia and 
those of the Macrophoma stage as raacroconidla. 

Cultures were made on various media, but as the fungus developed 
luxuriantly and rapidly upon corn meal, that medium was adopted for 


Oct ts, 


Fungous Disease of Hemp 


83 


the cultural work. The fungus developed in the same sequence as in 
nature, the Dendrophoma stage appearing first, regardless as to whether 
the cultures were made from microconidia, macroconidia, or ascospores. 
Sections of the pycnidia made at a later date demonstrated that the 
development of the macroconidia followed the microconidia in the same 
pycnidium. In sections made at a still later date asd were found develop- 
ing in the same locule with the mature macroconidia. The three spore 
forms of the fungus as developed in culture agreed perfectly in character 
with those found in nature. The variations observed in size and shape 
of macroconidia and shape of the asci were also exhibited by the fungus 
in nature. The one notable difference, however, was in the stronger 
development of stroma in the cultures. Since the Dendrophoma spores 
and the Macrophoma spores developed in the same pycnidia, the macro- 
conidia and ascospores in the same perithecia, and all three forms in the 
same stroma, it is definitely proved that these three forms represent the 
different stages in the life history of one fungus (fig. i, / 4 ). 

From the critical microscopical study of the Dendrophoma stage of this 
fungus in nature and in culture it is shown to be morphologically identical 
with a specimen of Dendropko^na marcomi described by Cavara in Italy 
in 1887.^ No stroma is produced as the fungus occurs on the host, 
although a w^ell-developed stroma is produced in culture. This stromatic 
development is suggestive of the genus Dothiorella, hut it is not a constant 
character, and as the fungus agrees so closely with Cavara’s description 
of Dendrophoma on hemp,® the authors consider these two forms to be 
identical. 

During the course of the microscopic study of Dr. Cavara’s material a 
second type of spore was found which corresponded exactly w'ith the 
macrospores discussed in this paper. No mention of these was made in 
Dr. Cavara’s paper, however, and the writers were unable to determine 
whether or not they had been observed by him. 

Among the few fungi described on hemp and related genera no species 
W'Cre found possessing the characters of the perfect stage of the fungus 
here discussed. In 1831 a fungus was observed by Schweinitz on hemp, 
and was called by him Sphaeria cannabis Schw.® This species is of histor- 
ical interest only, for the description is too meager to be of any taxonomic 
value. The characters of the ascosporic stage place the fungus in the 
genus Boiryo sphaeria as defined by Saccardo.'^ As the imperfect stage of 
this fungus is considered identical with the first described form, Dendro- 
phoma marconii Cav., the specific name is retained and the fungus is 
designated Boiryosphaeria marconii (Cav.) Charles and Jenkins. 

Botryosphaeria marconii (Cav.) Charles and Jenkins. 

Perithecia globose, perforate, diseased area pale olive buff to gray, 14.0 to 160 {i in 
diameter; basidia bearing microconidia mostly dichotomously branched, septate, 
hyaline; niicroconidia polymorphic, ovate, elliptical, or terete, continuous, hyaline, 
4to5>^ hy lyi to 2 ji\ macroconidia fusiform or ellipsoid, continuous, hyaline to glau- 
cous, 16 to 18 by 5 to 6 /i; basidia of macroconidia slender, generally 12 to 15 /i in 
length; asci clavate, 8-spored, 80 to 90 by 13 to 15 paraphyses filiform; spores 
fusoid, hyaline to pale light grape green, 16 to 18 by 7 to 8 Microconidia, macro- 
conidia, and asci produced in the same peri the cium. On Cannabis sativa. 


I Ftmghi Parasslti delle Piante Coltivate od Utili. 


^ Briosi, Giovanni, and Cavara, Fridiano. 

1887, ExsiccaUx. 

^ddiano, Appunti di patologia vegeule (alcuni funghi parassiti dt piante cultivate.) In Att i 

2I V. I, p. pb. im. 

Synopsis fuagorum in America borcali media degentium secundum observa- 
J^Tram. Amer. Phil, Soc., n, s., v. 4. p. 331. no. 1741. 18^4. 

Sylloge Fungomm ... v. a.p, 433. Patavii. iSSj. 


baccardo, p. A, 


Saccardo, p. A. Sylloge Fungonun 


V. I, p. 456. Patavii, 1883. 



84 


Journal of Agricultural Research 


Vol. in» No. , 


In view of the serious nature of the disease and its sudden appearance 
in America it has seemed best to present this preliminary paper. The 
true parasitic nature of the fungus was evident from its effect on the 
growing plants, but its parasitism was further demonstrated by the suc- 
cessful isolation of the fungus from the interior tissue of thoroughly disin- 
fected stems. Owing to Umited time and opportunity for extenave field 
observations, many questions relating to the pathological phase of the 
subject remain unsolved. Problems pertaining to the method of infec- 
tion by the fungus, its manner of dissemination, and control measures for 
the disease are still subjects of investigation by the Office of Pathological 
Collections and Inspection Work. 


PLATE XI 

A hemp plant, showing upper branches attacked by the fungus Boiryosphaeria 
marconii. 








A more accurate method of comparing first- 
generation MAIZE hybrids with THEIR PARENTS 

By G. N. COLUNS, 

Boianistf Office of Acclimatization and Adaptation of Crop Plants, 

Bureau of Plant Industry 

INTRODUCTION 

That the crossing of two distinct varieties of maize usually results 
in an increase of vigor and larger yields in the first, or F^, generation 
has come to be generally recognized. The amount of the increase, how- 
ever varies greatly in different hybrids, and in many cases the increase 
is not large enough to be determined by ordinary experimental methods, 
if it exists at all. 

So far as known, no case has been reported where a decrease below 
the mean yield of the parents has been adequately demonstrated. It 
is highly desirable to know the conditions under which significant in- 
creases occur, but thus far little light has been thrown on this important 
point. If really incompatible varieties exist, a study of their behavior 
in hybrid combinations should afford a favorable opportunity to learn 
something regarding the conditions necessary for large increases. One 
serious obstacle to learning the factors involved in the increased yields 
of first-generation hybrids is the difficulty of accurately comparing the 
vigor and yield of a hybrid with that of the parent varieties. 

Hybrids in maize are made either by hand pollination between indi- 
vidual plants or by planting in alternate rows the varieties to be hybrid- 
ized and removing the tassels from all the plants of one of the varieties. 

The customary method of comparing the behavior of a hybrid with 
its parents is to plant the hybrid seed in rows or blocks alternating with 
similar areas planted with the seed of the parents. If the series is re- 
peated a sufficient number of times, reliable averages may be obtained, 
but in actual practice the number of repetitions is usually limited by 
lack of seed or space.^ 

In making a comparison between a hybrid and its parents where the 
hybrid is made by planting the varieties in alternate rows, the question 
arises as to what seed will best represent the parents. If the original 
seed of the parent varieties is used, it will be one year older than the 
hybrid seed, and the uncertain element of deterioration with age is in- 
troduced.* By saving the seed from the plants used as a source of pollen 
in making the hybrid, fresh seed of the male parent can be secured, but 
if fresh seed of the female parent is obtained, it must be grown at some 
distance from the place where the hybrid is made. To use seed grown 
under different conditions introduces an element of uncertainty that 


* In experiments with maize extend tnt; over a number of years in many different localities, we have 
lOMd that with rows loo feet long and the series repeated lo times, it has seldom been possible to detect 
with assurance differences in yield of less than lo per cent. 

' For a discussion of this point, see Hartley. C. P., Brown, E. B,. Kyle, C. H., and Zook, I,. E. Cross- 
breeding com, U. S. Dept. Agr., Bur. Plant Indus, Bui. aiS. p. 13-16. 1913. One and two-y^r-old 
of selection No. 119a, the variety used as male parent in the Maryland experiments, occurred side by side 
43 times. The average superiority of the new seed was 7 ± t.3 per cent. 


J^raal of Agriailtural Research. Vol. HI, No. i 

D^Pt. of Agriculture, Washington, D. C. Oct. is, 1914 

G- 3 S 


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86 


Journal of Agricultural Research 


Vol. HI. No, , 


may be as serious as that incurred by the use of old seed. If the condi- 
tions of growth where the pure seed is produced are more favorable 
than those under which the hybrid seed is produced, natural selection 
will be less rigorous. There is also the possibility of direct effect of en- 
vironment on the yielding power of the seed and the possibility of new- 
place effect. 

A further disturbing factor lies in the differences between the indi- 
vidual plants that produce the hybrid seed and those producing the pure 
seed which is to represent the parental varieties. When seed from a 
large number of plants is used, these differences tend to counterbalance 
each other and give an average of value for practical purposes, but in- 
formation which might extend our knowledge regarding the nature and 
causes of the increase may be completely obscured by this method of 
averaging. 

Some of these difficulties can be avoided if the hybrid seed is obtained 
by hand pollination. By this means seed of both parent varieties of the 
same age as the hybrid seed and grown under similar conditions can be 
secured. Inaccuracies due to diversity among individual plants will, 
however, be increased, since the number of plants involved will necessa- 
rily be smaller, and, as before, differences in the behavior of individual 
crosses which might throw light on the nature of the increases will be 
masked if conclusions are based upon averages. To avoid this last diffi- 
culty, the individual hybrid ears may be kept separate and an ear-to-row 
method of making comparisons with the parents may be applied. 

Differences in the breeding value of individuals are now appreciated in 
the breeding of pure strains and have led to the adoption of the method of 
separating the offspring of individuals into progeny rows. The results 
here reported show' a diversity among the hybrid ears that result from 
crossing different plants of the same parent varieties that is even greater 
than that usually found between pure seed ears of a single variety, and 
the evidence indicates that individual diversity in hybrids will be found 
as important as in pure varieties. 

In comparing an individual maize hybrid with its parents account must 
be taken of the fact that to behave normally maize must be cross-polli- 
nated, and to secure cross-pollinated seed of the parent varieties two 
plants of each variety must be used, but only one plant of each variety 
can be represented in an individual hybrid ear. To avoid in some 
measure these sources of inaccuracy the method follow'cd in the experi- 
ments here described is suggested. 

DESCRIPTION OF METHOD 

To compare the behavior of two varieties, which may be called A and B, 
with that of a hybrid between them, two plants were selected in each 
variety, Ai and A2 in the one variety and Bi and B2 in the other variety. 
The following hand pollinations were made: Ai XA2, A2XB1, B1XB2, 
and B2 X Ai. The result is two hybrid ears and one cross-pollinated ear of 
each variety. It is believed that the mean yield produced by seed from 
the two hybrid cars compared with the^mean yield produced by seed from 
the two pure seed ears gives a fair measure of the effects of hybridization. 
By making tw'o hybrids involving all the plants used in producing the 
pure seed ears individual differences that affect the yielding power of the 
pure seed cars are similarly represented in the hybrids. Thus, in both the 



First-Generation Maize Hybrids 87 

Oct. »5. 


arents and the hybrids the average yield represents the mean yielding 
^ wer of the four parent plants, the only difference being the way in which 
the individuals are combined. 

To secure the most accurate comparison of the yield of the four ears, 
ne seed from each of the ears was planted in each hill. The different 
kinds were identified by their relative position in the hill. To place the 
seeds accurately, a board 4 inches square was provided with a small, 
nointed peg 2 inches long at each comer. These pegs were forced into 
the soil at each hill, making four holes, one for each of the four kinds, 
only one seed being planted in a hole. The board was always placed with 
two sides of the board parallel to the row. It was necessary to exercise 
extreme care in dropping the seeds to avoid changing the position of the 
kinds. The best way to obviate mistakes of this kind is to make all the 
holes of a row in advance and to go down the row with one kind of seed 
at a time. 

At harvest time the seed produced by each plant was weighed and ■ 
recorded separately. All hills that lacked one or more plants were 
excluded and the comparison confined to hills in which all four kinds were 
represented. The method of handling the yields was to determine the 
mean yield of the four kinds in each hill and to state the yield of each of the 
four plants as a percentage of the mean of the hill in which it grew. The 
percentage standing of each kind in all the hills was then averaged to 
secure the final expression of the relative behavior of the four kinds. 

This method of comparison is similar to the ingenious plan originated 
bv C. H. Kyle/ for use in ear-to-row breeding. Kyle's method is to plant 
each of the ears to be tested in a separate row and in each hill to plant 
one seed of a standard, or check, ear with which all ears are compared. 
Since comparative and not absolute yields are desired in the study of 
hybrids and with only four kinds to compare, the introduction of a check 
in the present experiment would have increased the space occupied by 
the experiment without lessening the experimental error. 

APPLICATIONS OF METHOD 

The hybrid tested by this method was a cross between the Egyptian, a 
white sweet com, and the Voorhecs Red, a related sweet variety with red 
aleurone .2 The two hybrids secured in accordance with the foregoing 
method were designated Ph96 and Ph97. The use of the Voorhees Red 
variety as one of the parents made the comparison unusually difficult. 
This variety produces a considerable percentage of albino seedlings, and 
since no albino seedlings reach maturity, the result was a large number of 
hills with less than the full complement of plants. Eighty-four hills were 
planted, but only fifty-eight matured plants of all four kinds. 

The comparative yield of the four kinds is given in Table I. To illus- 
trate the meaning of these determinations, let us take the yield of the 
Egyptian variety. The number 112.8 indicates that the yield of 58 
Egyptian plants averaged 112.8 per cent of the mean yield pee plant of 
all fojr kinds — that is, 12.8 per cent above the mean. 


' Kyle, c, H. Directigas to cooperative com breeders. U. S. Dept. Agr., Bur. Plant Indus., B. P. I. 

10 p,, igio. 

of Egyptian com used iti this experiment was from cnrmitercial seed secure*! from J. 
tnorbum Sc Co. in 191 1. The uriK;iuul siiuk*? td the V^x)^ht‘es Ret! was an cur kindly supplied by Proi. 
oyron D, Halstcd, of the New Jersey State Agricultural Extwiimcot Station, in 1907. 



88 


Journal of Agricultural Research 


Vol. in. No., 


The mean of the two parents is 84.2 ±3.0 per cent of the general yield. 
The mean of the two hybrids is 1 15.9 ±3.3 per cent. The mean yidd of 
the hybrids is thus 31 .7 db 4-5 per cent higher than the mean of the parents 
and this increase is ascribed to the effects of crossing. 

Table I, — Yield and height of the Egyptian and Voorhees Red varieties of sioeet corn 
and two hybrids between them 


IDetemunations expressed as average percentages of the mean of the four hinds.] 


Variety of com. 

j Yield. 

Heijht. 

Hg^yptian 

Per cent. 
n2. 8±4. 6 
55 - 6 ± 4 .o 
S g-ois. I 
142. 8±4.3 

Per cent. 

84. 0 i .9 
100. 0±I. 2 
103. 6±n 

Voorhees Red 

Hybrid Fhg6 

Hybrid Ph97 



A striking feature of the results obtained is the difference between the 
yield of the two hybrid ears, which amounts to 53.8 ±6.7 per cent. Had 
the ear PhQh alone been taken as representing a hybrid between these 
varieties, the hybrid would have exceeded the average of the parents by 
only 4.8 per cent, a difference upon which no reliance could be placed. 
If, on the other hand, the ear Ph97 had been taken, the difference in favor 
of the hybrid would have appeared as 58.6 per cent. 

The relative height of the four kinds was determined in the same 
manner as the yield — that is, the height of each plant was compared 
with the mean height of all the plants of the hill in which it grew, the 
latter being taken as 100. The average heights expressed in this way 
are given in column 2, Table L 

The average height of the parents is 97.6^0.7 per cent of the general 
mean. That of the hybrids is ioi.8±o.8 per cent. The difference is 
4.2 ±1-1 per cent. There is, then, a distinct increase in the height of 
plants as a result of crossing, but the increase is much less than the 
increase in yield, and the difference between the two hybrids is much 
less than was the case with the yield. 

It has usually been found that the increase that follows crossing affects 
the vegetative characters even more than the reproductive. If height 
be taken as an index of vegetative vigor, the reverse would seem to be 
true in the present cross. 

Increased vegetative \ngor may have resulted in an increase of the 
branches rather than of the main stalk. To definitely settle this point, 
it would have been necessary to weigh or measure all of the suckers. 
This was not done, but the number of suckers was recorded for each of 
the kinds, and the difference, though small, indicates that a part of the 
increased vegetative vigor of the hybrids was expressed in the production 
of suckers. A total of 18 suckers was produced in the two pure-seed 
rows, while 35 were produced in the two hybrid rows. The association 
between vegetative vigor and yield is further shown by the fact that the 
hybrid Ph97 exceeded the hybrid Phgfi both in yield and in the produc- 
tion of suckers. It should be borne in mind, however, that an increased 
yield and an increased production of branches may not always be thus 
associated. It is to be expected that under some conditions excessive 



Oct, IS. 19*4 


First-Generation Maize Hybrids 


89 


branching may result in a decreased yield. Hence, if some hybrids show 
reduced vields, this fact alone should not be taken as proving an excep- 
tion to the general rule that the first generation of a hybrid shows 
increased vigor. 

The method of comparison here used brings the plants into close com- 
petition, and it maybe urged that the differences between the kinds are 
^ a result unduly accentuated. With a view to detecting a possible 
effect of competition, the yield of the plants in hills with four plants was 
compared with plants of the same varieties in hills with less than four 

^tid Ph97 the yield per plant was slightly higher in the 
A-nlant hills than in the 3 -plant hills. The differences were, however, 
insignificant. In Phpb the yield of the plants from the 3-pIant hills 
exceeded that from the 4-plant hills by 67 grams per plant. The number 
of 3-plant hills was so small, however, that little confidence should be 
placed in the difference, which was but three times the probable error, 

^ An attempt was made to secure a more accurate comparison by cor- 
recting for the differences in the yield of the different kinds, thus making 
it possible to compare the yield per plant of all the 4-plant hills with that 
of all the 3 -plant hills. The average yield per plant in the 4-plant hills 
was 211 ±7 grains. The average yield of the 3-plant hills was 227 ±10. 
The difference of i6±i2 grams is therefore not significant. 

With such a large experimental error it is of course not impossible 
that the crowding of the plants has a tendency to reduce the yield, but 
if so the difference is too small to be measured by the means employed, 
If crowding operated to accentuate differences, it might also be expected 
to retard the dale of llowering. The average number of days to flowering 
was, how^ever, the same in the 4- plant hills and in the hills with less than 
four plants, being 72.4 days in both. Thus there is no evidence that 
the growing of the four kinds close together affects the relative yield of 
the kinds, and when ample space is provided bctw'een the hills, viz, 
4 by 5 feet, as in this experiment, it is believed that this source of inac- 
curacy is insignificant. 

The conditions of the experiment here reported constitute a severe test 
of the method of comparison by individual hills. The kinds tested were 
very dissimilar, while the soil of the experiment was unusually uniform. 
The gain in accuracy secured by using the hill as the unit of comparison, 
instead of averaging the yield of all the plants of a kind, may be measured 
by a comparison of the standard deviations or the coefficient of variability 
observ'cd when the yields are compared by the two methods. 

When the yield of each plant was compared ivith the average of all the 
plants of the same kind, the coefficient of variability was 5.42^:0.17. 
When the yield of each plant was compared with mean yield of the hill in 
ivhicli it grew the coefficient of variability was 5.05 ±0.13. There is, 
thus, a slight gain in accuracy, notwithstanding the exceptional uni- 
formity of the soil where the experiment was tried. With less uniform 
soil conditions the advantages secured by making the comparison on the 
basis of individual hills would increase. 

The dates when the first staminate flowers opened and when the first 
silks appeared were recorded for all the plants. The average number of 
days from planting to flowering is shown in Table 11 . 

60300®— 14 7 



90 


Journal of Agricultural Research 


Vol, III, No, X 


Table II . — Average time from planting to flowering of varieties of maize 


Variety. | 

Number of 
days to first 
pollen. 

Numbered 
days to first 
sillcs. 

Egyptian ... 

73 .o±o. I 
72. l± . 2 
72. oi: . 2 
72- 5 ± ■ 2 

1 ' 
73-9± o .3 
77- .3 

73 - Si -4 

73- 6 ± .4 

Voorhees Red 

Hybrid Ph 96 

Hybrid Phg; 



With respect to the appearance of the staminate flowers the only 
significant difference is the slightly later flowering of the Egyptian variety. 
With respect to the appearance of silks, the Voorhees Red, the low- 
yielding variety, was distinctly later. The average time between the 
opening of staminate flowers and the appearance of silks was less than 
one day in the Egyptian and five days in the Voorhees Red variety. 
Both hybrids were intermediate, with 1.5 and 1.1 days, respectively, 
between the average time of the appearance of pollen and silks. 

A further comparison of the hybrids with their parents with respect to 
minor characters brings to light a number of striking differences. A 
comparison of the characters measured is made in Table III. 


Table III.^ — Comparison of minor characters of maize hybrids with their parents 


Character. 

Eg>T>tian 

Voorhees 

Hybrid 

Hybrid 

At'crage of 

Average of 

maize. 


Red maize. 

Phi;6. 

Ph 97 . 

parents. 

hybrids. 

Height cm. . 

206 

± 1 

6 


2. 6 

1S5 ±3-4 







Number of suckers , , 

. 3 


04 

- ii± 

- 03 

■ 14L -03 

-48± .08 

• i6oi: 

022 


3 ± -041 

Total number of 













1 ^ ^ 



15-3 ± 


16. 4 * . 13 

10- 8 :n . 14 



0.8 

16. 6 


Exsertion of tassel a 









cm. . 

4-3 

i 

3 

4 - y ± 

■ 3 

V 2 ± .2 


4.6 

± 

20 


± .17 

Length of axis of tas- 
sel b cm. , 

Length of central 


± 

3 

16.6 ± 

• 3 

lf>- 4 ± -3 

14 - I ± . 3 

14. 1 

t 

>9 

15. 3 

± 20 

spike * cm . . ! 

Number of primary : 

2S. I 

± 

H 

i 

i ± 

. 8 

24 - S ± r 

29 - T ± I- 1 

25- ^ 


33 

37. 1 

± . 74 

branches in tassel. ,1 
Number of secondary 

14. 4 

± 

'' i 

19- 3 ± 

■ 3» 

20. I ± . 35 

15-4 ± -17 1 

16- 9 

± 


17.7 

± .72 

branches in tassel. 

5 

± 

I 

6. j ± 

. 2 

7- 2 — ■ 3 

1 4 - 7 i ; 

t-b 

± 

35 

5. 9 

± .i3 

Length of longest leaf , ' 
Number of nodes 

59- 3 

± 

5 : 

84 ± 

.3 

89- 6 i; I 

! 9*- 9 ± . 7 ; 

sis. 6 


47 

Of. 3 

± .63 

above longest leal. . 
Number of nodes 

5-6 


0 

4-5 ±' 


4 -9 -f 1- 3 

5-1 ±1.0 , 

S- > 

± 

7 

5 

i .73 

above ear 

S-3 

± - 

•S ' 

4-9 1 

■ 4 

: 4. r ^ - r. 

4-9 rr .0 . 

5- > 

* 

Jf> 

4-S 

± . 4 f 


o Measured from the top of the upiiermost leaf sheath to the lowest tassel branch. 

* Measured along the axis from the insertion of the first to the insertion of the last primary tassel branch. 
® Measured from Lusertioa of last tassel branch to tip of tassel. 


In all of the characters measured, with the exception of “Number of 
nodes above the longest leaf” and “Number of nodes above the car," 
there was a measurable difference between the two parents. In the 
“Number of suckers” and in the four tassel measurements there was also 
a significant difference between the two hybrids. The mean of the 
hybrids shows a close approximation to the mean of the parents in the 
total number of leaves, exsertion of tassel, length of the central spike, 
number of secondary branches, and number of nodes above the ear 
and the longest leaf. The characters in which the hybrid exceeds the 



Oct JSf 


First-Generation Maize Hybrids 


91 


parents are for the most part those more cjosely associated with vigor — 
viz, height, number of suckers, and length of leaf. The differences 
j^etWen the two hybrids are such that without exception Ph96 stands 
closer to the Voorhees Red variety and Ph97 closer to the Egyptian 
variety. It is probably a coincidence that in both hybrids the resem- 
blance is to the female parent, 

CONCLUSIONS 

So large a proportion of first -gene ration maize hybrids have been 
found to give increased yields and the increase is frequently of such 
magnitude that the utilization of this factor of productiveness becomes a 
practical question. It is therefore highly desirable to understand the 
reasons why some crosses give favorable results and others give little or 
no increase over the yield of the parents, A necessary step in this 
direction is to develop a reliable method of measuring the effect of 
crossing, apart from other factors that influence yield. 

The development of satisfactory methods of comparing the yield of 
first -gene ration hybrids with that of their parents has been retarded by 
(t) a failure to fully appreciate the importance of individual diversity 
in hybrids, (2) the abnormal behavior of self-pollinated maize plants, 
and (3) the difficulty of securing for comparison hybrids and parents 
with identical ancestry. It is believed that the method here described 
avoids these difficulties and affords more accurate means of comparing 
first -gene rat ion niaize hybrids with their parents. 

The method is illustrated by an experitnent in crossing two varieties of 
sweet com in which it was found that the progeny from one hybrid ear 
yielded nearly double that of the other hybrid ear involved in the ex|>eri- 
ment. To have taken either ear alone would have led to entirely erro- 
neous conclusions regarding the increase secured as a result of crossing. 
The increase in x'ield due to crossing as measured by the method here 
proposed was 31 per cent. 



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