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ALBERT R. MANN LIBRARY

AT

CORNELL UNIVERSITY

ae Wes eee Gee One

DATE DUE

DEMCO 38-297

Cornell University

Library

The original of this book is in the Cornell University Library.

There are no known copyright restrictions in the United States on the use of the text.

http://www.archive.org/details/cu31924052338088

To Dr. T. L. Lyon, the author wishes to express his appreciation for the kindness in directing the investi- gation herein treated.

And to Dr. J. A. Bizzell, who made the chemical

analysis of the soil solution.

THE CAUSE OF INJURY TO MATZE BY WEEDS.

A MINOR THESIS

Presented to the

DEPARTMENT OF EXPERIMENTAL AGRONOMY CORNELL UNIVERSITY

For the Degree of

MASTER OF SCIENCE IN AGRICULTURE

by

Clement Ellis Craig, B. S.

June, 1908.

fi;

(Gf

ee Cee

ee eee oe)

CONTENTS

INTRODUCTION

HISTORICAL Effect of Weeds on Yield and Quality of Produce Effect of Weeds on Soil Moisture Composition of Weeds, Corn,Millet and Cowpeas

Effect of Weeds on Fertilizing constituents

of the Soil :

Effect of "Weeds" Growing in Corn on the Total Salts and NO3 Gontent of the Soil

franspiration

The Relation of Transpiration to Plant Food Transferred to the Plant

Capillarity

Influence of Texture of Soil upon Moisture Content and its Relation to Yield of Corn

Diffusion of Soil Nutrients

Drought Limit

Interruption of Water by Plants

Effect of Weeds on Light, Warmpth, and Protect- ion from Air Currents

Effect of Weeds in Producing a Toxic Substance

Page

19

27 30

34 36

53 55

CONTENTS

Effect of Weeds by Root Interference Effect of Scraping on Soil Moisture Effect of Scraping of Yield of Corn Effect of Mulching

EXPERIMENTAL Purpose of Experiment General Plan of Experiment Detailed Outline of Experiment Map of Plats Description of Plats Fertilizers Applied

Preparation of Land, Planting and Cultivation

Moisture Determination

Determination of Fertilizer Constituents in

the Soil Weather Sonditions Growth Injuries Sustained

Harvesting

Effect of Stand on the Weight of the Stalks

Yield of Com Fodder by Rows

Page 56 57 59

62

65 = 129 65 65 66 68 69 69 70 72

73 74 75 76 76 77 82

CONTENTS . Page

Determination of Dry Matter 90 Yield of Corn, Milley, and Say Beans 93 Average Moisture Content of the Soil for

Different Periods 99 Differences in Moisture Content of the Soil

for Different Periods, between the Ends

of Plats and where Corn Grew; also the

Variation in Yields. 103 Average Fertilizer Content of the Soil for

Different Periods 107 Results secured from First Sowing of "Weeds",

Plat 5: 109 - lil

yield p. 109; moisture in soil p. 110;

NOg content of soil p. 110; comparison

of the reduction of moisture and NOg 9. lil. Results secured from First Sowing of "Weeds",

Plat 9: 112 - 114

yield p. 112; moisture p. 113; NOg con-

tent of soil p. 115; comparison of the

reduction of moisture and NOg p. 114. Results secured from Second Sowing of "Weeds" 114

Results secured from Third Sowing of "Weeds" At?

CONTENTS.

Results Secured from Mulching;

Comparison of moisture and NOg con-

tent of the soil

Results secured from Scraping

Comparison of the moisture and Nog

content of the soil

Comparison of Mulched and Scraped Plats

Variations in Fertilizer Constituents

Yield of Nitrogen in Crops

Amount of NOS Remaining in Soil

Capillarity of Different Plats

APPENDIX.

Moisture and Fertilizer Content of the Soil,

in Detail (Table A) Further Soil Studies

Poor Space and Specific Gravity

Poor Space, Suggestions for Determining

Rate of Evaporation and Loss from Drainage:

from platinum dishes p. 155; from cyl- inders of soil p. 155; the "fairly uni- form level" in cylinders of soil p. 163; rapid fall at end of the “fairly uniform

level, p. 165.

Page 117 - 119

118 119 - 121

119 121 diel 124 - 127 126

Le?

130 - 145 146 - 169 146 152 153 - 169

INTRODUCTION

— > te fon Sal

That wesds cause injury to erops is a fact about which there is no difference of opinion. The exact cause of this injury, however, is not so well understood. Two reasons &re usually assigned, namely, the loss of moisture and plant food. Some experimenters emphasize the former, while others lay greater etrees cn the latter. Some seem to consider the two causes as equaliy injurjous. That weeds lower the moisture content is the common experience of farmers and there is also very conclusive experimental data on this point. The belief that injury results from loss of piant food seems to be based chiefly on reasoning from general principles and from the chemical analysis of weeds. Another cause assigned, based on experimental data, is the lowering of the soil temperature. One asserts that the lowering of the temperature hinders the efficieney of the roots and iessens the decay of organic matter. Sheding of the crops is another cause assigned. Again root interference is proposed ; and the possibility of a toxic effect has bern suggested.

Thus it will be seen that there are many explanations

either singly or in combination, offered for the well-known

phenomenon, that weeds injure crops. Two of these causes,

however, in the opinions of experimentalists stand pre-

eminent ; namely, injuries due to loss of soil moisture,

and to loss of plant food. The chief attention was, there~

ei fore, directed to these causes,

The thesis is divided as follows :

i. Historical 2, Experimental 3. Appendix. In the historical part, the literature is reviewed and discussed. * In the experimental part, an account of the experiment is given, together with discussions chiefly in the lisht of the historical treatment. In the Appendix, a limited study of the soll under

experiment is made.

HISTORICAL

Effect of Weeds on Yield and Quality of Produce.

The Minnesota Station (Bul, 68, 588)"in 1898 pianted corn

in drills in two piats in @ similar manner, the piats being

run in duplicate, On ons plat the corn was cultivated

thoroughly, no weeds being a@ilowed to grow, and a loose

mulch of earth two or three inches deep was mainteined

throughout the early part of the summer. The other plat

received but slight cultivation, the weeds being allowed

to grow freely until July 21, when they were removed by hand,

and the soil cultivated." The weeds grown were mostly e

pigeon grass, and were mature when harvested. The results

are shown in Table I.

fable I ; Showing Effect of Yeedsa on Yield of Stover

and Ear Corn, Rate per Acre.

Corn Weeds Far Corn Stover Ear Corn Total and Stover

Well cultivated 4824# B703#f 12762 12762#

Poorly cultivated 35404 25924 3653# 69so# 10529#%

A yield of 3540 pounds of weeds reduced the yield of corn fodder (stover and ear eorn) 5773 pounds or 45 per cent ; the reduetion in the yield of ear corn was 2232 pounds or 46 per cent. The percentage of ear corn was nearly the same in both cases. The rate of reduction in

yield due to weeds was 1.69 pounds corn fodder for each

pound of weeds. These results refer to weights at harvest~

ing. Had dry matter bean determined doubtless there |

would have been found & greater per cent of dry substance

in the pigeon grass than in the corn. But the yieid of

corn fodder on the pleats is compsérable, and shows a marked

reduction. The New Hapshire Station (Bul, 71, 54)

compared two plats of eorn, both cultivated ; but in one

witch grass was allowed to grow, while in the other the

grass wags cut with @ hoe. The results follow in Table II. Table II ; - Showing Effect of Witeh Grass on

Cultivated Corn - Results Rate per Acre.

Kind Culture Stover Shelled Corn Lbs. bus.

Hood 11843 81.6

Not Hoed 9188 61.4

The grass caused @ reduction in yield of both stover and shelled corn. The yield of stover in the plat not noed was 77.6 per cent of that where hoed and the yield of shelled corn 75.2 per cent, thus showing a slightly greater reduction percentagely of shelled corn than of stover. Ths same Station (Bul. 71, 50) compared corn with no cultivation, weeds being permitted to grow,with

eorn cultivated, The rasults follow in Tabie III.

Table III : Showing Effect of Weeds on Yield of Cora

Kind of Culture Stover Shelled Corn lbs. bus.

No Culture, weeds fadwWing 4420 LT wl,

Cuitivation, frequent 12016 80.6

Cultivation, ordinary 11496 79.1

The weeds caused a great reduction in yisld both of stover and shalied corn. The yield of stover where wsede grew was 38.4 per cent as much as where ordinary cultiva- tion was given, and of shelled corn 21.6 per cent. Manifestly the quality of shelled corn was lgwered.

The South Carolina Station (Bul. 61, 11) grew cown

peas in corn for two years with the results shown in Table

IV. Table IV: Showing Effect of Cowpeas on Yield of Ear Corn : 1898 1899 Average bu. bu. bu. Corn, no cowpeas 58.0 66.8 68.4

Corn, cowpeas in drills between rows 60.0 69.9 64.9 Corn, cowpeas broadcast i" " 64.0 73.2 68.6

The corn was planted in rows four fest apart, one stalk to the foot in each case. Peas sown in drilis

showed an increase over no peas both years and peas broad-

cast showed a still greater increase. Whether the in- crease is due to peas being aA leguminous crop or to some other cause is a question. The results seem to suggest the importance of distinguishing between “weeds" when studying their effect on either the soil or the crop.

At the Cornell Station during the summer of 1905, Cates conducted experiments to determine the effect of “weede" on corn, The “Weeds" were rye, miilet, and miscellanecus weeds. TableVis adé@pted from Corneil Bul. 247, 186, and shows the yield of both corn and “weeds. The table is arranged in Jjenes I, II, and IIIf, and shows the effects of rye, aitiews and miscellaneous weeds respectively. In each series, plats 1 and 4 are checks. In the colum "Productive Capacity, Corn Fodder" is shown what presumably would have been the yield of corn fodder had no "weeds" been grown on the plats. These figures for plata 2 and 3 are@ caéleuléted from the checks 1 and 4 where no "weeds" grew.

"Plates 1 and 4 were cultivated throughout the whole period of growth, viz., about once in ten days from June 14 to August 22, On June 14, piat 2 was cultivated when Series I was sown to rye, series II to millet, and series IIT

‘:

allowed to grow to weeds without furthsr cuitivation.

Plat 3 was cultivated June 14 and again June 27, when seach

series was treated as plat 2."

T able V ;: Showing Yields per Plat of Corn and "Weeds"

Green Weight Field Cured Series Corn with Rye No. productive aor Rye otal inerease(+)Stover Bar % Ear Plat Capacity Fodder Decrease («) Corn Corn Corn fodder to Podde lbs. lbs. lbs. lbs. lbs. lbs. lbs. 1 ch 216.9 216.9 216.9 59 46.3 A4 2 224.3 105.2 75 180.2 w4A 1 38 21.5 36 3 231.7 131.1 78 209.1 22.6 38 3540 48 4 ch 239.0 239.0 2359.0 63 48.9 AS Series II with Millet No. Productive sore illet Total nCPeaSeTe) Plat Capacity Fodder Decrease (~) Corn fodder lbs. lbs. lbs. lbs. lbs. 1 ch 122.5 122.5 38 33 46.5 2 2S od 49.1 100 149.1 424.90 30 3 9 4 ch 1350.2 130.2 40 38 49

Series Iii Corn with Weeds No. Productive Corn Weeds Total Increase fe) Plat Capacity Fodder Decrease (-) Corn Fodder lbs. lbs. Lbs. lbs. Lbs.

1 oh 103.8 103.8 103.8 33 0-35 51.5 2 126.6 53.9 42 95.9 “30.7 26 11 30 3 149.4 104.1 45 149.1 ~ 25 42 32 43

4 ch my ep a Oy oe & 172.1 A? 88 55

Series I, giving results with rye, shows a decided decrease in total green weight of produce, Series II with millet shows an increase, and Series III with weeds shows a decrease, Had dry matter been determined it is probable that, if the results had been averaged for the three series, the total produce where "weeds" were grown would have excecded that of the checks. Allowing for the probable difference in dry matter between corn fodder and miilet, the results in Series II show a very decided increase in total produces where millet was grown in the corn. The corn fodder as indicated by the green weight suffered a much greater injury in this series than in series I and III.

Of field-cured etover where "weeds" grew the injury is not nearly proportionate to that of total fodder. The yieid of plat 3, Series II is practicaliy equal to that of the checks. ut the yield of ear corn is much reduced in every case. The per cent of sar corn to fieid-cured fodder is iess in every case where “weeds" grew except in plat 3, Series I. This reduction is most marked both in weight and per cent of ear maize in Serivs II where millet grew. There is dese injury in ererycase to ear corn from the later sowing of “weeds” (Plat 3) than from the first sowing (Plat 2) : Manifestly, the lowering of the quality

further emphasizes the injury.

10.

While not directly applicable to corn, perhaps, some

results from German and Scandinavian sources

with

miscellansous crops wiil be helpful as indicating general

principles. From én abstract in Fuhling's Landwirthsch-

aftliche Zeztung, XLIV (1895), 355 is derived Table VI :

Table VI : Showing Effect of Weeds on Crops

Kina Past No Weeds With Weeds erns. %@ whole gerns. % whole plant piant Grains 349 ae 2686 20.8 Peas Straw 130i 1018 ° Grains 850 37.9 479 34.1 Field Beans Straw 1390 919 Av. tuber 575 35.8 Potatoes All tubers 27775 12775 Roots 13680 70.4 1819 84.4 Kohlrabi Leaves 7009 1390 Roots g000 79.4 338 50.7 Garden Reets Leaves 2333 329

Injury

per cent

23.8 22.4 44.7 34.6

54.0 89.4 85.7 96.38 85.9

The number of potatoes where no weeds grew were

483 and with weeds were 357.

The injury in every case is marked being the most

severe with the root crops. The percentage of injury was

uniformally greater with the grain and roots than with the

il.

straw and leaves.

From @ Scandinavian source the results in Table VII are taken (FE.5.R. 15, 683)

Table VII : Showing Effect of Weeds on Yield :

Results given in kiloprams per Hretame.

Crop Part No Weeds With Weeds Crop and Weeds Total Crop Wecds Decrease(-) kilo kilo kilo kilo

Hay 6180 2890 1740 4630 -1550

= Grains 2246 833 4975 ~1066 Barley

Straw 3795 8407 1735 Potatoes Tubers 22101 11330

The decrease in yield of crops is marked in every case, a yield of 1740 pounds lowering the hay yield 3290 pounds. 1735 pounds of weeds lowered the yield of barley grain 1413 pounds, and of barley straw 1358, making a total of 2801. The percentage of injury to the srain was much greater than to that of straw. The decrease in total yield was also marked. This is espscially interesting since it is usually supposed that both hay and bariey have relatively large water requirements, as weil as weeds,

The foregoing data, while giving unmistakabie indica- tions, would have been more valuable, especially for the

purpose of a soil study, had dry matter been determined.

However, presence fodder ; was much

taken as

12

except wheres cowpeas were <rown in the corn, the of "weeds" in every ease lowered the yield of corn and usually the percentage of ear corn to fodder reduced. The data showing the total yield if

reported, also usually show @ decided dsecrvase,.

Rut had dry matter been determined, the writer is of the

Opinion that the resuits would be very conflicting.

The

effect of weeds on low-growing crops in Europe is

more marked than on corn in this country, This may be due

partially at icast, to the greater shading. Whers the

yield of waeds are reported (p.//) in these European tests,

the total yield is much reduced.

43,

PLfect of Vecds on Moisture, Experimentera are

agreed thet one of the injurioue effects of weeds on erors

is the robbery of scil moisture, Warrériton states (Physical Properties of Soils, 125) that weeds are moat injurious in @ dry climate, It is further genoraily supposed thst wesds require more coisture for the croduction of @ given aneunt of dry matter than do moet S@ricul tural plants. aye and Smith (Minn, 98, 548) itn referring to pigson grass (hich was used in on experiment toe determine their #ffect on corn) seams to voice ths genarsi belief

asp £9 @ll weeds by stating, that it is quite probable that these weeds use mors water in producing & pound of dry matter than doas corn,

The Kinnesota Station (Vinn. 88, 588) in the experiment just referred to (Also sex p. 4) found that the moisture in the corn plat woere nu weeds crew veriad from 36 to 20 par cont (data approgimated from graphic tabie) “hiie where weeds were growing in the corn the variation woe from 49.5 to 7 © a difference between the minimum of 13 % against whe7vweeds grew, These variations occurred betwaon June £9 ond July 23 just ufter the weeds were pulled. On August & the moigstura in the wead-free pint reachea 17 2, which wae the iowsat of the season,

Assuming that this was about @e Lowest t.%) oflare 0 nat.

i4,

the corn could extract the moisture from the soil, it appears that 10 % more moisture was availabie for the weeda than for the corn. Tha rapidity with zhich the weeds

consumed the moisture is shown ae foiluws ;:

Date Rainfail % Moleture (i) July 7 1.44 in, 49.5

- i3 32.5

" AG 18.9

" is 255

8 id 14.5

" 96 7.9 ;

(1) Per cent moisture approximite? from graphic etatement.

Since the weeds were pulled July 21 the lowset moisture content was probably reached on that date. These woisture determinations were made by ths ¢leectrical method.

King (Ru, Soils, 26, 44) determined the moisture content on the surface foot of two soiis which were in wesdy fallow. The results were averages from thirteen fields in #ach case. The Ssima siit loam contained 6.83 % and the Goldsboro compact sandy loam, 3.64 % moisture.

At the Corneli Station (Bul. 247, 186) experiments were conducted with rye gid miliet, and weeds in corn.

The data gives the average per cent of moisture taken at intervals between June 27 and Auguet 15. Table VIII is

quoted :

15.

Table VIII : Percentage of Moisture on Cultivated and

Weed Plate :

Plat Treatment Series I Series II Series IIt M@ize with Maize with Maize with yy millet weeds L Cultivated 24.7 20 eh 26.8 2 "Weeds" after June 14 2°.0 24.8 Z2ied 3 "Weeade" after June 27 23.6 2:i.9 22.3 4 Cultivated ; 26.3 28.38 24.6

These resulte show 4 de6crease in every case where “weeds" grew in corn. Fad the season bean ary and the Gata given in detail doubtless @ sreater variation against

"we-ds" ac:bome periods would »4 shown.

16

Composition of Weeds, Corn, Miliet, Soy Beans, and

Cowpeas.

Cameren (Bu. Soils, 2%, 6 ) observes, that different crops and even the same crop under slightly varying condi- tions remove not only widésly different amounts,but widely different proportions of mineral constituents from the soil,’

Snyder (Soils and Fertilizers, 194) states that, ‘the amount of fertiiity remcved in weeds is usualiy greater than that in agricultural plants because the weeds have a greater pover of obtaining food from the ail, Again, the same author (Minn. Bul. 101, 244) says that, "weeds' neve large amounts of water and proteids. There is more protein in dry matter of purselane, vig weed, Lambs quarter, cheese weed, and catnip, thén in either aifalfa or clover. The drain on land by these weeds is beeause of the nitrogen they sontein,

The Florida, West Virginia, and Minnesota Stations heave made numerous analys#s of weeds. Table /X , showing

data on the composition of weeds as well as analysés, of some

agricultural plants for comparison, 18 45 foilows :

17

fable /X ‘: Showing Composition of Weeds, Corn Fodder, Millet, and Soy Beans =< Dry Matter.

Plant Number Authority WN. PoQ5 Ke2d0 Ash Analysis % a z “f Weeds 49 Average W. Va.19 1.62 .83 2.52

Poke Weed 1 Max.Comp. " 3.538 .65 8.00

Broom. Sedge 1 Min. *" id 278 421 68 fall Ragweed 1 , 1.36 .414 1.79 Weeds 15 Average Minn.101 2,81 16.51 244 ° Pig Weed Max, W * 4.26 Field Shuttle Min. W . eot Lamb's Quarter Max. Ash 18,34 Goldenrod Min a 6.89 Pigeon Grass 2.60 Lea tT Purselaxeé Max. Comp. Fla. 11 4.05 26402 Cotton ' Head Weed Min. s ” ol 5.66 Corn Fodder 35 oe 1.256 4.7 Millet 1 ‘Afeads “42, partly filled 38 2.05 8.6 Millet 1 In bloom os 1.41 §.8 Millet 1 Winn.Rept. 1894,/3% 1.18 10.17 Millet 12 Dry fodder 0.8.5. il, 14 «=1.30 6250 qowpesa & " Hay 2.98 8.50 Soy Beans 6 Green fodder * 1.92 9.50

Soy Beans 1 Cut Aug. 30 "76 2.42 £50

18

The tabie shows a wide variability in thse composition of weeds, This atrongiy suggest the necsesity of noting the characteristics of the particular weed with which any experiment is conducted to determine their effect on another crop. Further, it suggests possibuiities in soil studies since by the proper selection of weeds to grow on the soil uséful variations may be secured.

The nitrogen content cf millet ssems to be slightly higher than in corn fodder, and the ash content is decidedly higher. Toubtlegss the composition of miiiet varies as widely as does that of corn, Soy beans are d«cidedly

higher in both nitrogen and ash than corn fodder and cowpeas.

19

Effect of Weeds on Fertilizing Constituents.

It has been noted above (p. /7) that many weeds possess a very high nitrogen and ish contsit. It wou.d appear that they might cause injury by removine either nitrogen or the mineral elements. On i&nd where phosphoric acid or potash or nitrogen is highly beneficial to crops, it wouid sesm reasonable that a weed with @ high ash 4nd nitrogen content would causes injury by removing the deficient element or élements whatever they might be. Put in the discussion undsr this head, nitrogen will recsive -the greatest snare of attention, since nitrates ceasa to forn after the soil molsturs reaches a certain iow timit, and since the nitrates in the soii show a rreater variability than the other #ssential elements, Gonsiderable attention will be paid to phosphoric acid, and but little will be given to potash. The potash requirement of soiis is not so variable as either phosphoric acid or nitrates, and data is not so available.

Snyder (Soils and Fertilizers, ii5) states, "Nitrifica- tion cannot take place in @ soil deficient in moisture. AS in S14 fermentation processes, 60 with nitrification, moisture is neesseary for the chemical changes to take placed. In a very dry time nitrification 1s arrested for the want of rcter."

Warrenton (Physical propertiss of Soils, 85) refers

to experiments by Schloesing Jr. (Compt. rend. CXXV, 824)

upon the sffeet of amount of water on the nitrification

of Ammonium sulphate. The experiments wery made en artificial mixturss of sand and clay in various propor» tions, including @ smeis: quintity of ehnik. The same percentage of water was added to exch mixture for the m&in line of the experiment. A further variation wes secured by adding more water to the more clayeynixtures. The rate of nitrificution, where the same amount of water was added, was more rapid in the sand than in the clay. "By increase ing the percentage of water in the soils containing the most clay, the rate of nitcification was raised to that observed in ths sandy soiis. He (Sechioesing Jr.) con- cludes that the different rate of nitrification is mainly due to the different thickness and therefore availability of the water film coating the particl~s of thé various

mixtures,”

20.

Where weeds or any other crop rapidly lower the moisture

in the soil, it would seem that there would be less nitrate formed than where the moisture condition isa good.

Ying (Bu. Soils 28, 52 ) gives the variubility of water sclubis NO, and HPO, in the surface four feet in eight etates ap foiiows ;

NO; varies in the proportion of 1 to 8

mPO4 " i" " " nm" R 4&4

21

In ¢ach case l represents the amallest amount of the respective constituent found.

In another table (p. ) is siven the renze found in @ight soil types.

NO3 varies in the proportion of 1 to 5.8

HPO, * a % " ei * ge

K - » : ot ee

Cameron and Beil (Bu. Soils 30, 67) state that

Yenaly ses of & number of extracts obtained from several types of soil of widely different origin and composition have yielded gan avsrage for potassium (K} of 27.3 parts, and for phosphoric acid (P04) 8.5 parts per million solution, The approximate uniformity of the individual rssuits makes it Qppear improbable that a furthsr accumulation of data would change these averages figures materially.”

In August and September (Bu. Soils 26, 49, 56,) thirty- two determinations were made of the water soiubie acid redicies in the soil under corn. There was 4a wids varia tion of soil types, studied in various states. The data is the sum of results for four fest and is accordingly given in parts per four millions (ppym) dry soil. The range of NOx, ppA{ m was 3.17 to 334.32 , 12 ren below 10 pp. m. , 37% of the determinations snowed isse than 2.5 p.P.M. NO, per foot. The rénge in BPO, was 2,44 to 39.56 ¢.p.thme

These show a wide variability for both NO, and HPO4,.

22

The acid radicals were determined ©>: in the soil under ootten for the lst, 2nd, 3rd, and 4th feet,’ Norfolk sanity soil (Bu. Scils 26, 39). The results follow in Table xX.

Table XM : Amount water Soluble WO3 and HPO4 in Soile

under Cotton in Norfolk Sandy Soil, Goldstruo, N.C.

Surface Foot 2nd Poot Month Heo Oz HPO, H,, 0 NO; H Oy April 10.13 28.70 186.20 16.42 30.01 11.30 Mey 9.96 50.00 10.56 13.01 9.03 4.28 June 6.95 37.58 9.86 11.39 4.78 7433 July 3.41 2.99 10.21 7.29 1.74 8.82 August 5.26 £2.54 272 8.46 32a 1,94 Sept. 3.74 1.30 2.88 8.93 -98 2.24 % rd Foot 4th Foot April 16,28 22.70 9.70 19.19 38.40 9.30 May 15.75 8.07 3.61 16.55 14.93 3.23 June 13.85 6.51 6.70 15.61 10.72 4.82 July 11.73 7.66 6.94 14.95 12.88 8.98 August 10.99 4.60 077 14.16 12.30 279

Bert. 12.61 4.88 1.55 14.81 14.76 2239

23

These results show in a general way that the NOs lowers with the moisture. The results in the surface foot in May and June, however, show @n increase, “uithough there is e Slirht decrease in moisture. But for this period there is « decided decrease in M0. in the second and third feet. In July when the lower soil s*sms to be unabl+ to permit any material amount of NO, to be transferred to the surface the fall in this radiclée was extreme, The moisture for this period was very Low. In Auguet the mcisture in ths surfacs hid increased considerably, but there was no corresponding incr:-ase in NOg. In the fourth foot there Was considerahie reduction ef NOs, in May, and a Blight reduction in moisture. After this period the amount of NO.

3 content. Tt is hardly probable that this was beneath the

wasp fairly constant with @ slight decrease in moisture

action of capillarity had there been sufficient moisture in the surface, The roots of the cotton piant doubtless penetrated somewhat into the third foot of soil, but did not reach the fourth foot. The data shows a valuable reserve in this soil beneath three feet, accumuiated by leaching from the surfsce which under the proper conditions of capillsrity would be of material advantage to the pant. The HPO 4 was considerably higher the first month than later at e@ch depth, and lowest in August. It has been

noted that the moieture content was increased during this

24

month @nd presumably the Y should haves been also. Wag there &n increase in N. not shown in the table which caused & greaier consumption of HPO»? And HPO 4 being the less ciffusible, if it improbable that for a short period it was the limiting factor réther than NO. ? In general the 4PO4 decreases with the depth, but would not seem to bs a@ limiting factor except possibly in August.

The results (Ru. Soils 26, 47) on the Poccosam soil show @ decided faii in NO, in the surfaes four feet, not» withstandine an increase in noisture as showg in Table XI.

Table X/: Moisture and NO., Content in Poccosan Soil

Where Corn was Growing.

Date Moistursa NO, HPO, he pp 4m pp. 4m Aug. 37 2065 dou ¢ BL 14.20

In a wooded tract of large trees on Goldsboro compact sandy loam, th: NO, lowers very much more rapidiy than the moisturs in each of the surface four feet of soil (Bu.

Soiis 26, 45). The fourth foot, just referred to above, is drained as ecmpletely of its N95 as the aurface foot. Me difference to which the roots penetrate, perhaps at least

is a factor in causing the variation. The PO, is much

25

more abundant in the surface foot than below. While the minimum is not as low as in the Norfolk sandy soil, diffusion would seem to be less effective, which gives rise to the suspicion that is may have been equally as difficult for the plant to secure as was NOy. As in the Norfolk sandy soil, the lowest proportion HPOq, in each of the four feet occurs on one date, which in this case is May 23.

The above series of data indicates the gensral while doubtless

4° ¢ deficient in some cases, does not generally seem to show

variability of NOg and of HP9O4. The HPO

the variability which NOs does. It would be expected, therefore, that any plant growth which made large demands on these substances, would make rapid and large changes upon the soil content of these radicies,

The effect of weeds growing a@ione upon the acid radicles as compared with those where crops were cultivated is shown by King (Bu. Soils 26, 44). The results which

follow are given for the surface four feet :

26

Soil from p.p. 4m. pep. 4m. Single field, best care 18.95 26.05 20 fields, less care, average 27.53 35.51 13 fields, weedy fallow, : 6,30 39.54

Goldsboro compact, sandy Loam ;: Single field, best care 17.85 Best? 20 fields, less care, averace 25.94 22.64 13 fields, weedy fallow, " 9.33 20.45 Wooded tract 17.54 23.23

Hs,

While there may be @ question about the results being strictly comparable, the poverty of NO3 is very striking, and especially so if it remembered that thsess results are in parts per four million (pp 4m.). The HPO, shows a dewided increase when weeds are growing in cons case, and a very slight decrease in the other instance. It would seem clear that the NO3 is entirely too iow for proper pliant growth,

The Cornell Station (247, 187) gives the total sOluble salts and NO, recovered where rye grew in eorn and NOg when millet wae likewise grown. The following table

ghows the adapted results :

27

Table XII: Eféect of "weeds" Growing in Corn on the Total Salts and NO, Content of the Soil. Series IT, Corn with Rye Series II Corn with Millet

No. Treatment Totai salts Total salts NOg ppm NOg ppm Plat ppm June 27 ppm Aug,25 Aug, 25 Aug. 8

1 Cultivatea, no "weeds" 600 329 160.9 23.0

2 (i) "weeds" sown June 14 644 180 LS. 70S

3 OWnacan” sown June 27 55f 226 29.9 7.4

4 Cultivated,

no "weeds" 519 329 165.0 eae

(%) "Weeds" refer to rye and miliet respectively.

The total galts show 4 decrease on Aug. 25 as compared with June 27, In plats @and 3 wheneweeds grew the reduc tion was much mors marked than on the checks, @nd of these more marked where the wesds were sown earlier in the season. Whether the essential ehements varied to correspond with the total ealte is &@ matter of conjecture. Put the variation of the NOs dus to "weeda" was very marked. The variation between the check plats is also great, due doubtivss in a iearge measure to being taken at different dates, There was further a great difference in the NOg in the cheek

piats, Aug. 8.

28

Hosford, under Professor Hunt's direction (Cornell 247, 190-192), approached the probiem in a different manner. Sodium nitrate was applied to the end of a plat (462) Table XII, where miliet was growing in corn. This part of the plat is designated as 462 N, after the fertilizer was applied, The growth on the whole plat was ssriousely checked as compared with the check plats where corn was growing @Lone and receiving cultivation, When the sodium nitrate was applied, the moisture in this plat, judging from the averages of soil moisture, was not low snoygh to cause the

laek of growth, but the NO, in the soil was running very

3 low. "Twice the amount of nitrate of soda necessary to supply 86 parts per miilion of dry soil to 2,909,990 of soil or to a depth of 8 inches was applied to 35 hilis of the maize plat, known as 462 N.on July 6, 14, 21, and 27, or four applications in all. At the end of the first week or on July 14, both the maize and the millet were much greener than the ref of the plat (462) net so treated, but it could not be said with certainty that the growth was ereater although it seemed « shade ionger ; on July 18, however,

the hills were distinetiy larger than the other hills of

the millet plat, and as green as the plants on the eulti- vated plat."

The water soluble nitrogen is shown in table xXIIT,

29

Table XIII: Variations in Water-soluble Nitrogen.

Date 461 Cultivated 462 Millet 462 N End of 462 plat in maize whieh was fertilized. PP @ PP a PP m@

May 31 56.4 40.0

June ll 80.0 80.90

June 22 73.9 60.0

July 2 96.0 10.0

July 8 68.5 11.5 21.8

July 19 52.7 7.5 48.0

July 30 12.3 3.8 « £699

Aug. 16 25.9 743 320.0

Aug. 21 10.5 9.6 218.2

Aug. 29 6.2 2.8 282.5

There can be little doubt that the inereased size and vigor of the plants in plat 262 N was due to the inersase of NOg in the soil.

Ineidentaily, it may be noted that the NO. in check plat 461 probably ran too low for good plant growth on Aug. 21 and 29.

30

TRANSPIRATION

The loss of water from the soil when plants completely cover the ground is chiefly through the pianta. Generally, weeds lower the moisture more rapidly and to a lower limit than corn (see discussion above). Plants also vary in the amount of water required to produce 4 pound of dry matter. Warrenton (Physical Properties of Soils, 53) has eolleeted data which follows in Table XIV :

Table XIV : Water Evaporated by Growing Plants for

One Part Dry Matter Produced :

Results obtained by

Lawes and Gilbert Hellriegel King Wollny

Beans 214 Feans 262 Maize 272 Maize 233

Wheat 225 Peas 292 Rarley 393 Millet 416

Peas 235 Barley 310 Potatoes 423 Peas 477

Red Clover 249 Red Clover 330 Red Clover 453 Sunflowers 490

Parley 262 Wheat 359 Peas 477 Buckwheat 646 Ruckwheat 371 Oats 557 Oats 665 Lupine 373 Rarlay 774 Rye 377 Mustard 843 Oats 402 Rape 912

31

Wide variations oceur in the amount of water required to produce @ given weight of dry matter in different plants. In the two columns where corn occurs, isss water is required than for any other plants given. Millet occurs only in Wolliny's results, and requires 74.25 % more water than corn, Peas, on which data is given in the table, shows 235, 292, 477, and 477 parts, respectively for cne part dry mateéer, The figures given by Lawes and Gilbert show a greater economy Of water than the others. Is this seonomy due to the moist climate of England, to the manner ef conducting the experiment, or to somes other cause ? The results from the Serman investigators di’fer widely.

King (fu. Soils, 26) conducted experiments on trans- piration from the corn plant on four different soils. The s0il was placed in barrels and @ constant supply of water maintained one foot from the surface, Evaporation from the soil surface was included in the transpiration results. When the eorn made 4 very poor growth, the proportion of water required was about three times 4s great as when the growth was 2ood, Manifestly, where the evaporation is included in the results, the data is untrustworthy &s showing the transpiraticn. Yet the data has practical value and

supports King's general observation, that where the trans-

32

piration (ineluding evaporation) is Large, there is @ Larger proportion of dry matter produced than when the transpiration is emall, The inclusion of evaporation from the surface with the transpiration by some experimenters, and its exclusion by others, together with different rates of

growth would be sufficient without other varying factors to cause the difference observed by the investigators quoted.

King (Wis. 8 Rept, 126) caleulated the amount of water required to preduce @ pound of dry matter uncer field con- ditions. Bariey required 402, oats 591, arfd corn 301 pounds of water, Variations due to evaporation and capiliarity wore included in the data, Hays (Ninn. 68) ealculated that wheat under field conditions required 261 pounds to produce & pound of dry matter.

Warrenton (Physicai Proverties of Soils, 52) observes that, the relation in question (between transpiration and dry matter produced) appears to be fairly definite so long asp certain conditions remain constant, but to vary under a wide range of circumstances. Further (p. 53) : "Two circumstaneses seem especially to influence the relation of water suppiy to produce ;

1. The amount of water supplied

2. Its riénness or poverty in plant food.

33

These two circumstances are palatively connected. Fhen the S0il contains little water, the solution in the soil is com- paratively concentrated in character, When much rain has fallen, the supply of water in the soil may be ampice, but

it contains very littie plant food. "The presence cf

much soluble saline metter in the soil is probably 4@ check

to @ rapid transpiration of water by plants."

34

THS RELATION OF TRANSPIRATION TO PLANT FOOD TRANSFERRED TO THE PLANT,

<> See One Gem On et Ot om Ge mR ow me

There seems to be two means of transferring plant food to the plant, viz., diffusion, and the mechanical transfer in the stream of water, The older piaént physiclogists seom to lay a ereater stress relatively on the formeethan do later investigators. Storer, conforming to the visws of the older investigators, cites the Yardian ease, and plants growing in the greenhouse where the air is moist, as showing the importance of di’fusion. He assumes that transpiration is not sufficient to cause the required trans- fer cof pliant food, May not the passage of water through the plant due to root pressure be greater than is assumed ? And may not the plant food in the artificial soiis usually employed under such eircumstancss be more abundant, thus, perhaps, requirins less water to produce 4& given amount of ary matter ? Ref@ering to the mechanical transfer of plant food, Losw (Bu. Piant Industry 45, ll), states that,” the surplus of mineral matter found in p.ants,nutrient as weil as indifferent compounds,- depends to a@ great extent uron

the intensity of the current of transpiration, which explains

35

why herbaceous plants show @ higher percentage of ash for the dry matter than do the ieaves of woody plants.” Warrenton (Physical Properties of Soils, 51) states, "The greater the evaporation (transpiration), the greater the transferrence

of plant food from the soil to the plant."

36

CAPILLARITY

me

The writer under Professor Fippin's direction deter- mined the capillary rise of water in four air dry soils of different textures. Soil 1 was secured by separating a coarse, sandy s0il with & helf mom. sieve, that which failed to pass through being retained. Soil 2 wes secured from that which was sliminated in securing Soii 1, and which failed to pass throursh a tenth m.m. sieves. Soil 3 was @ silt loam, and was not passed through a sieve. Soil 4 was a caked ciay loam, which wés broken down with @ redler and. passed through @ half m.m. sieve. Giass cylinders 40 c.m. internal diameter were prepared by firmiy tying @ dan of folded cheesecloth over one end. The soil was cérefui.y placed in the tubes, avoiding the formation of air spaces. The cylinders were s6ét in pans in which water was maintained at &@ depth of about two inecnes. The results on Table XV refer to rise above the water level.

Table XV ; Capillary Rise in Solis of Pifferent

Texture: ~ in Inches.

37

Capillary Rise at Different Periods

oe iO mm. l hr. 8 das. 7 das. 13 das. 27 das. 48 des. oil

i 7 8.5 11.9 12.3 13.3 14.7 16.2 2 8.5 10.7 13.2 °14.8 15.7 17.2 19.0 3 3.5 7.1 88.8 655.5 65.0 72.0 or top

4 1.7 16.1 18.1 22.5 28.7 35.7

The coarse soils 1 and 2 show athe most rapid rise in the beginning, but fail~ far behind toward the end of the experiment. Soil of medium texture permits the water to rise rapidly, diminishing toward the .Lact,e when it reached the top of the cylinder. Noubtlees in time the riee would have begn considerably higher had the column been longer. Soil 4 showed a slow rise, and judging from the results in capillary tests by the California Station, it is probable that it would never have reached above 48 inches. Ved it been convenient to determine the rise in moistened soil, the capillary rise would have been greater and perhaps the comparative results would have been comewhat different. These differences, however, indicate the great variations in the capillary power of soils - differences which shouid be eliminated as far as possibie in experimental work, When the gol is put under speeiai stress, such as groving

"weeds" in corn, the variations due to this cause might

38

reasonably be expected to very seriously modify results. Warrenton (Physical Properties of Soils, 101), quotes experiments on capillarity made by King (Wisconsin Station) when the water was maintained at different depths beneath the surface, The results follow in Table XVI. Table XVI : Fate of Capillarity, where Vater was Maintained at Different Tepths from the Surface,

Pounds per Square-foot Surface,

Soil Nistance Water Level Teneath Surface i ft 2ft. 3 ft. 4 ft.

Fine Sand 2.37 lbs, 2.07 1.23 91

Clay Loam 2.95 1.62 1.09 99

t

The evaporation or amount transferred to the surface by capillarity wes sufficient where the water was four feet beneath the surface "for the most luxuriant growth."

These results, however, are not secured in the field since erops suffered with the water table within five feet of the surface, The roots would easily penetrate to within four feet of the water tabise. Warrenton assicns ag a reason for this that in the laboratory the soils are usually screened so that the particles are of a fairly uniform size, while in the field there is @ greater varia-

tion ; and that the water level in the field does not #ipply

39

moisture as readily as artificial supplies in the laboratory. The objection that the soils used in the laboratory are different from the Field, soils, however, does not apply to the Wisconsin results. ‘The same author (p. 105) further states ; "The practical effect of capillary action in raising water to the surface of the soil to the level oecupied by plant roots, has apparently been very much exagerated ; its influence on the distribution of water in the soil is never- theless very iarge."

Some Florida trucking soils (Bu. Soils 13, &, 9,) however, seem to pessess 4 remarkable power ‘of maintaining a sufficient, although very low, percentage of moisture. "The soil. is a coarse white or yaliow sand underlaid by a coarse sandy subsoil. It Looks like a barren sea sand or a coarse sharp building sand, but that it is very productive is shown by the iarge and vigorous csrowth of pines, the luxuriant growth of frase, the great quantity of truck erops which can be produced during the season, and the enormous growth of begear weeds which take possession of the land after the crop is removed.” The surface is rolling, varying from 25 to 50 ft. Standing water is 15 to 20 feet beneath the surface. After a rain the surface ineh or two ig soon as dry as dust, but the moisture 3 te 68 inehes

beneath the surface never falis below 3 % and perhaps 4 %

40

to 5% is optimum. At 6 % the soil is quite wet. No

shoratge of soil moisture occurred during the period of

observation, although there were periods of 15 to 20 days

without rainfall, fechanical analysis shows 94.87 % medium

and fine sand in the surface soil, and 95.28 % in the subsoil, ‘nost of the remainder was coarse sand. There is thus an

unusual uniformity in the size of the soil particies, a

condition which Warrenton suggests is favorable to eapillarity

Yet this author thinks possibly the remarkabis results

in this soil may be due to condensation. The fact that

it is situated in a peninsula, together with the depth of

the water table, wouud give credence to this supposition.

Rut Whitney, in support of the theory that the result is

due to ca&pillarity, cites soils in dry climates of Southern

California and Texas, where it is not unusual for crops to

thrive for a period of five or six months without either

rainfall or irrigation.

This difference in ¢apillary power suggests an explana- tion for Hosford's resvits (Cornell 247, 189) where the largest yields of corn fodder were secured where the soil moisture was the lowest. The resuits are given in Table

XVII, which is quoted as it oceurs is the bulletin.

41

Table XVII : Influence of Texture of Soil upon Moisture Content and its Relation to Yield of Maize. South Series Nerth Series

Water per cent Maize Fodder lb. Water oxr cent Maize Fodder

17.8 762 14.7 903 16.9 73l 13.8 904 25.1 778 11.9 859 14.6 O72 i226 L002

Hunt, in discussing the rcveults (p. 189) observe 3 "The differeness in the psreentage of moistufre in these plats are dus to the eharacter and perhaps the topography of the scil, the lowsr percentages being on the sandier and higher ground. In general the lower the percentage of moisture, the larger the yield of maize. It is extremely unfortunate that thse proportion of water soluble nitrogen was not determined by these piats." Yhiie the amount of soluble nitrogen is suggested 4&8 an expian&tion of the differenee in yieid, the relative coarseness of the soil of plats producing the best yields, would in the light of pesos ebtained in the laboratory, and observed in the Florida soils, indicate a higher capillary power,

The size of soil particies which have the greatest

capillary power appears to be larger than is usually supposed.

42

RELATION OF CAPILLARITY TO TRANSFER OF FERTILIZING CONSTITUENTS,

ae ee oy ee om

King at the Wisconsin Station (sce p.3¥), found that after evaporation experiments had run for some tims, saits accumulated on the surface in sufficient amounts to ninder the loss o8 water. The same investigator, when discussing the high salt content in ths upper four feet of some soiis, observes ; "It is the writer's judgment that the relatively high salt content for the soils of Georgia dnd South Carolina are to & eonsiderable extant due to 4 protracted drought, which had prevailed in the regions where the samples were taken, and which, through capillary rise and long ané strong svaporation had concentrated the saits in the zone sampled.”

Warrenton (Physieal Properties of Scils, 191) states that, ‘salts may be concentrated in & soiid form or «8 & strong solution at the surface ; this is especially the case after active nitrifieation, after Grourht, or especially and to the greatest extent after the application of 4 dressing of sa@iine manure. Opposed to this tendency to accumulation at the surface we have the action of rain which

fe tends to carry ail soluble salts into the subsoil.

43

The alternate movement of the water upward and downward perheps explains the sudden increase of soluble nitrogen noted at times date in the season, Where rain occurs after an accumulation on the surface of nitrates désrived either from the soit or from an artificial application, the nitrates beneath the surface wiil increase, Probably if the soil sampis includes the surface soil, such sxd7%em fiuctuations would not occur, There 18, however, another possibility in @ high rate of nitrification dus to 4a good moisture and temherature condition. If the plants shovid cease to use soluble nitrogen some time previcus to taking the soll sample, ‘there would be an additional cause for un increase of this

constituent.

44

DIFFUSION OF SOIL NUTRIENTS,

Warrenton gives the relative diffusion of salts 4s determined by Mérignac, as shown in Table XVIII.

Table XVIII : Helativa Diffusion Cosffiecients of Salts.

Ralative Piffusibility Relative Diffusibility of Acide of Pasis Potassium Salts Chlorides Suiphates Nitrates

Chicride Li4 Potassium 1.56 1.46 1.55 Nitrate 100 Ammonia 1.25

Sulphate 69 Soda 1,90 1.00 1.090 Cerbonate 50 Caleium — 65 66

Magnesium 055 o DL 064

There seems to be a diserepancy in the results in the relative diffusibility of the chloride and nitrate of po- tassium being in ons case 1.14 and 1.00 respectively, and in thse other 1.56 and 1.55. Ths table, however, shows that galts containing tne bases potassium and ammonia ané the acids chlorine and nitrogen are relatively highly diffusible.

When the satis are diffusing together, the rate is giightly different from that where diffusing separately. "Me rate of diffusion of the more diffusibio sults is

generaliy very neariy what it would be if diffused alone,

45

whiig the rate of diffusion o8 the less diffusible sait is distinetly diminished. The relative diffusibiiity 18 aso sometimes affected by the strength of the eolution employed

While phosphoric acid is not shown in the table, it prohably has 4 Low rate of diffusibiiity.

The abundance of the water greatly affeets diffueion,. In water cuitures, proportions of viant food nutrients occur far below the amounts required, if they were oniy taken up by the piant in the proportions occurring in the solution. In sandy soils, therefore, the giffusion is better than in clayey soils on account of the gereater thickness of the water film. The hindering effect of adhesion wouid 4iso be relatively less in sandy soils. But it is found that in heavy soils, even, the nitrates are nearly eompietely taken up. King (The Soil, 117) states that “at the time the crops sre growing, the roots remove the nitrates, whene these roots are found, so thoroughly that the measured amounts at any one piacs is smeli, the plants tending to pick it up as rapidly as it may be formes. In the results of ths same author (Bu. Soiis 26), previously quoted, where wesds were growing on two types of soil the

nitrates were almost completely removed. There ls eon-

siderable water retained in field soils in all cases, hence,

by diffusion only, can the nearly complete removal of nitrates be uccounted for, Usualiy the phosphoric acid does dot fali reiatively so low in soii as nitrates. This may be due to the siower diffusion, or to the continuous solubility gsither in the Pieid or in the Laboratory, or te all combined.

While the mevement of soil nutrients for any consider abie distance in a@ reasonabie length of time is due to the mechanical transfer by the water of caplllarity or nereo- lation, the transfer to the rootlets after the root zone is reached is probably chiefly due to diffusion. Capillary water passing to the surface may bp this means be largely or nearly wholly divested of the salts which the piants require. Under such cireumstaneses the analysis of the surface soil for soluble plant food would gives littie indication of ths nutrisnts used by the plant.

Ths amount of piant food nutrients in a soil sample may not even approximately represent the amount used by the piant. Howsver, the amount of excess wouid probably in most cases be some indication. Where the amount was abundant, the piant would be well suppiied, but the amoukt might run down to a certain fairly or equaily low

limit, and the plant be nearly or equally as well supplied.

47

The regults of nitrogen determinations in drainage water (Ru. Soils 26 , Rothamstead Vemoirs, V. 91) from plats of wheat variously fertilized are interesting in this connection. This lend responds abundantly to nitrogenous fertilizer. The NO, ag nitrie acid found in the drainage water and the yields are shown in Table Xix.

Table XIX : NO ag Nitric Acid in Drainage Water,

ané Yield of Wheat at The Rothanstead Station.

The Amount NO, p.p.m. Arranged in Ascending Order.

NO3 Yieid ° "heat DePeM, Lbs. 3.9 1726 San 1988 8.5 3348 13.9 3587 14.9 5013 15.14 449.3 15.3 3716 16.2 5304 17.4 4967 18.4 6920 19.2 4716

The inerease in yield is correllated with the inerease

of NOg in the drainage water tiil i5.1 D.p.m. HO3 is reached,

48

after which the results very although the average is above that reached where there was 14.9 p.p wm. NOg, (This stétement is not strictly corrget sincs the r-suits were obtained from draingse water which passed through the sub- s0il some distence before entering the drain, Doubtless t*s amount of WO. given ig smaller than would have been secured had the determinations been madé where the roots were feeding ; but the ee@mpurative results wov.d probably heve not been far dirferent.) The difficulty in securing soluble nitrogén when the amount of NO; in this soli is below 14.0 p.%.m. Lf indicated, Vany facfors wou.d affect the limit below which plants would suffer for iack of soluble nitrogen, one of which would he the closeness of the roots of the piants, Tt if probabiy, the limit for corn would be higher then for wheat if the soi. moisture, temperature, a :c other conditions were the came,

When any erop with # ciosé roct system is growing with corn, is not the corn at an increasing disadvantars as the

limiting fertilizéng constituent was Lowered in the soil ?

49

DROUGHT LIMIT.

The drought timit, or the per cent of moisture in the soil, whef’ pients ceases to secure cuffileisnt moisture Por prowth, varies widely with ths soil and to 4 isss desree wath the planta,

The Fureau of Soiis eonducted evaporation experiments under uniform conditions upon different types of soil. The sviis were artificially saturated and gmail amounts were ured. The i958 1n welgnt was about uniform tili the optimum molelure Wes reaecned, efter which there wus a progressive Geerease in Loss till the hygroscopic moisturs was reached. There arpewred to be no Gefinite point at which the rate of evaporation changed till the soil became air dry. The Grought iimit, therefore, aprears to be ie reiation between the needs of the piant and th» progressively decreasing ebaiuty of the soii to supply moistursé, rither than any aefinits point at which the soil fails to give up moisture,

Numsrous determinations by King, Whitiney,and others show thy wide variation in the capaeity of soils in the fisid to give up moisture to plants.

Vawerich (Physical Properties of Soils 63, 64) deter- mined the wilting point of plants in different solis,

The piante were grown in very smail boxes tiil fully develop-

ed, and then piaced under conditions of very little evapora.

50

tion till they bsrin to wilt. The soil was then mixed and the water d-termined. The @iredry soii was 4180 placed in a saturated atmosphere to determine the hyrrog- eopic moisture, The results follow in the adapted table XX. Table ¥X : Wilting Point of Plants and Hygroscopie Moisture in Different Soi.s Employed.

Moisture per 100 Dry Soil &Pilting

When Plants Hygros. Point above

Soil wilted Moisturs Mygros. Mcisture. Coarse sandy scii Lee iai5 30.4 Sandy garden soil 4.6 3.99 ‘ 53.3 Fins humus send 6.2 3.98 55.8 Sandy logm Val 5.74 37.26 Peat 49.7 42,30 12.8

Ths wide variability of soils in their capaeity to give up water to piants is ¢liown, but ths wilting point is much below thet found by Whitney, King, and others under field eonditions, The p.ans employed in the experimsnt: would affect tne results. There 16 4 suspieion thst tha naoieture coniéent chown in these reeilts ig tco iow, due to rhe gmail containing boxes used, 4nd to nixins the soil Before determining the moisture. Tia 8014 ahovs where the roots were Peeding possibly approached the hygroscopic

wundition. Ths Wilting point 18 much nearer the hygros-

51

eopie moisturs than the results obtained by the California Station.

tne droueht Limits for weeds is lower thén for corn.

ta

(Sse discussion under Effect of Weeds on Moisture)

52

INTERRUPTION OF WATER PY PLANTS

Weber (Physical Properties of Soils, 129) estimated that in the forests of Switgzeriand, Prussia, and Bavaria

trees interrupted the falline moisture 4s forlows ;:

Larch 15 per cent

Birch 1 om Om”

Spruce Fir a = ° Seotech Pins eo SH! at

When weeds eover the surface, and the rainfall is in gaali amounts, the loss from this scurcs may at times be very muterial. Even when the rainfail is considerable the amount intercepted may overhciance the protection

against evaporation.

53

Effect of Wesds on Light, Varmth: and Proteetion from

Ait Currents.

In @ German experiment (&. S$. R. 16, 883 ; Fuhting's Landw. Ztg. 53) weeds growing in potatoes, beans, and maize lowered the temperature o to 4° C. through "shading and transpiration,"

The reesuits of aun experiment at the Minnesota Station (Bul. 68, 585), where the temperature of the soil where no vegetation was -rowing was compared with that where wheat was growing thouch not strictly comparable with weeds growing in crops, wouid nevertheless be of some value for this purpose, There the wheat was growing the temp-rature wae about 5° lower than where the ground was bars.

Manifestiy where weeds szrowing an eorn exeiudse the light from ths Lower leaves, the efficiency of this part woulé be leesened. Since soil bacteria require absen' a of light, if it possible that nitrification wiii occur @leeer to the surface than where weeds are not growing in corn, providing the moisture eontent remains the seme ?

Suppose a few small weeds were growing in corn, but having @ darce shading capacity for the p:ant food and water consumed ; wouid the surface soil have a better moisture condition for nitrifieation ? In ordinary fieid conditions

the scant moisture for mueh of the growing ss4son hinders

54

mitrification on the immediate surface,

If a limited amount of small weeds under the same eonditions shouid cause an inersase in nitraies, wiil ° there be @ sufficient inereass to more then balancs the amount of nitrates consumed by them ? There would he probabiy less temporary loss of food constituents by aceumulation on the surface,

It would scam, on the cther hand, that the lessening of the temperature of the soil mizht be detrimental, but this séems to be uncertain, If detrimenta: in & northern

. Latitude, wili if necessarily be true further south ?

Shade by lowering the temperature lescens evaporation from the curface of the soil. Corn whiie lessening evaporae tion does not accomplish thie result 418 weli 48 when weeds aré growing with it. Weeds Likewise S@ecist the corn in hindsring the movement of the Gir over the: surface, thereby lessening svaporation from the surfsce., Ying, (Wis. Rpt. hl, 309) found thut isss water was evaporated from 4 pan when placs] to the iseward of @n oak grove, hedge, and elover field. Thige w8s probably due both to ths lessening

of the velocity of the wind, and to the atmospherd: &cquir-

ing @ome moisture from the windbreaks,

55

Effect of Weeds in Produeing a Toxic Substance.

Aecording to an cl@ theory recently revived, piants producs in soils 4 substance which is injurious to plant zrowth. The work by the Tursau of Soiis sexms to etronsly indicate the correctness of the theory. It is claimed that plants vary greatly in the toxicity produced and that soils have different capacities in overeoming this unfavorshle condition, If the theory be true, is it not reasonable that some weeds would cause toxicity for a cultivated pliant ? .

Clark and collaborators (Corneil Bul. 247, 198)

found that scils denominated "poor spots” on account of the poor crops produced, contained a high content of nitrates. This soil when transferrea to the crsenhouse end puiverized, produced better pliant growth than that csnominaicd "gocd soil". "Good soll" refers to the soit whieh produced good crops under field conditions. Wag the poor production in the fieid dug to a toxic substancs which wus siiminated by eeration or sous other agency when transferred to the greenhouse ? Was there any relation between the conditions

producing hish nitrogen content and the injurious influence ?

56

Effect of Wesds bv Root Interferenes,

Paunnel (F.°.F. XK, 1048 ; Ia. 39, 52) states cqut “eome weede @re injurious because the network of roots prevents the fuil development of ths roots of the grain mea Other observers have assumed such injurious

effects, trvt so far os the writer is arere no conciusive

exp6ériments have been conducted.

5”

Effect of Serapine on Soil Moisture.

Warrenton (Physieal Proverties of Soils, 193) states that during six winter months, (“cetobsr to Merch) the evaporation from & water surface neer Lindon xse ¢.8 inches, and from a bare field at Fothamstead was 4.8 to 5.2 inenes, During the six summer months the evaporation yas 15,9 inches from the former and 11.1 to 11.5 inches from ths iatter.

differenes

oy rs

At the Pisoconaian Stetion (ept. 6, 205)

in moisture wes determined betweon ro.ied @and cuitiveted

plats. This sand was paoved in the eyring and the plats . ternated,. The results follow in Table Y XI.

Table XXI : Comparison in Moisture Content between

Rholied and Cultivated Land ; First Foot.

Date Roliet a rf Pp

May 29 15.4 17.2

June g Ligh L669

June 17 12,0 °° 46.0

June 29 15.9 19.9

July 17 11,8 14.1

The seeond and third fest showed a difference in favor

of the eultivated piats but was less worked than in the first

foot.

58

Snycer (Solis and Fertilizers) determined the

difference in So1i moisture in corn wheres given shallow

cultivation and whera not cultivated, The rasultse follow in Teble XXIT. Table ATILT +: Moisturs in Corn Fisid :

*

With shailow No cultivation

surfacys cuitivation

Soil, depth 3 to 9 in. i462 8.2% » f 4 Mag ft ine 12.88 &

The diffarenes in favor of eultivation is marked,

59

Effect of Scraning on Yield of Corn,

The South Ca¥oiina Station (Bul. 44,2 compared ecOrm CuitiveLss with corn not cultivated, Ac. paats ware pianied on tha iavel, Ths results are shown in Tuble XXIII, Teble UNTIIT : Comparison of Vield Ear Corn Cuitivated

and Not Cultivated,

Treatmeit Sound Corn bu. Total bu. Custiveted, isvel and shaliiow Bis 1 58.5 Cuil 28 £1Ck¢e tArouehsut oy ar 60.9 Not cuibtivated, wed and grags, 49,7 56.5

cut with nowy

There is but a siight decrease in yie.d where ths piat W4e8 scrapdd. The percénoesze of sound corn i8 about the Same.

The Illinois Station (Bul iS, 419) eomared the effects of eeYreping vith cuitavetion ior wbree Ageaweangs yvrars. The land ws biack prairie loam twenty inehss desp, undere icid with yeliow elay. In 1887 (the year before the expsriment begin) crimson clovsr was grown on the aand.

The surface was seraped at the usual time for cultivation ap follows : First year five times ; seeond year three times ; and ths third year four timss. The Last sersping was given on July 24, July 16, and Tune 25 and 26 for the respective years. Care was taken to disturb the soil 4s

little as possible when removing the weeds. The resulta

60

foilow in Table XXIV,

Table XXIV : Effect of Scraping on Yield of Corn :

.

Ne. Kind of cultivation Yieid per acre Average 1388 i284 4590 bu,

PL at bu. bue Dus

i Hood, ordinary 96 2.5 69.4 81.1

e Kone, we-ds scraped from surfaes 99 ?72.i 69.1 78.7

3S Shaisow, once «fter tasseling 94.4 e2.° 868.4 1.4

4 Deep, "“ ss Ms 65,2 79.3 59.3 74.9 5 Shaiiow, ordinary 93,8 34.6 66.8 81.7 5 Deep, , 84.9 74.2 89.8 73.3 7 Shaliow, frequent 94.6 BO.9 Flad 82,2 & Deep, . S455 684.8 65.4 74.2

(For a continuation of these experim-nts, 6-o Bul.

Wel an

and 31)

The i+Suits &re consistent for piat experiments. The sera.paed yiat shows out &@ siishtly less yield than the pest vists. Noubtiess some weeds grew in the intervals betwen sera@ping ,end uPterp "Laying by". Shousd we assume Shat gone weeds crew and that @ smali amount of wesds are Getriment«l uccording to She.sr quantity, it would he easy to eouncwude that chis injury wouid be suffieient to cause the Slicht Grerseass in yleid when compared even with the

best yléicing pices. if the soii moisture was lowered in

thie plat t9 correspond with that on bare land and in eorn above notsd, it would seem that the yield is nut eorrerlated With the woisturs an the soil wriess rnlate ere scraped. It wouid further seam to indisets some compensating Pactor or factors,

It 18 usuaiiy surnosed that cuitivation favors nitri- fication. ‘Snyder, (foils nd Pertilizers), 1i4) states

ikon NEO «ho : bee a that cuitivation, purticulariy of ciay soile favors nitri-

tt fication inereasin=s the suppl: of oxyren in the soil.

if this bs trues, ware the Titinois and South {arolina soils surficientiy rich in nitrates under the sunnvosediy un-=

favorable conditions for the nitrates not to be @ limiting

Pactor ?

62

Effect of Mulching.

The Geneva Station (7 Rept. 189) compared moisture a in duplicate plate not crowing piante 2: follows : Weeds pulled, cuitivated differsnt cepths,and milched, The results follow in Table XXV,

weable SV 2 Brfect of Pot.ine “sede, Cultiovetion ana

Muiching on Soii Moisture shore no Piente Crew.

Untouched Cultivated Mulen “eods pil. 28) 7/2" 2" 4" i in. short oat straw, - ¢ ¢ fo Average tuy BeQe6b 32 26.20 27.10 17.41 19.00 19.37 Aug. 8 14.2 Loe d 16.1 iG6et 19.0

The mulched plats show &n excess of moisture over the cultivated prats, which in turn show an exeess over the untouched piets, The difference 1s more marked during the dry weather.

Ebermeyer (Physical Properties cf Sviis,lii) found that the evaporation from artificially saturated soil within the for-st covered by iitter was during the Bix gumuer months only 46 ver cent af mucn 2s where no litter was employed. It 18 possible thet unces evrtain cireum- staneers the sulch applies @bout crops by tencing to prevent the solid moistvre resachine such a low stetus may maintain @ condition by which capiliarity mey be sore active. After

the moisture reeches below & esrtain limit there may not only

63

be @ lack of upward c4piliarity but ioss may oceur from percolation,

Qn the other hand @ muich intercepts moisture and

should therefore not be too thick. This wouid apply with

especial force if the rainfall is in gm@ii ancunts,.

-- EXPERIMENTAL --

65 =

PURPOSE OF EXPERIMENT

In the experiment herein treated it was not proposed to study all the possible causes of injury which weeds produce when growing in corn. The chief efforts were confined to the effects of weeds on the soil moisture and the fertilizer con- tents of the soil. Further variations were produced in the experiment by scraping and mulching the surface of the soil.

As the experiment progressed other variations than those inclu- ded in the plan developed. Although a consideration of some of these other factors may not be strictly in line with the pur-

pose of the experiment, their inclusion is neverth8less believed

to be warrented.

GENERAL PLAN OF THE EXPERIMENT The plan of the experiment included the following

comparisons:

Fertilization VB No fertilization "Weeds" No "Weeds"

Small growth of "Weeds"" Larger growth of "Weeds" Cultivation " Mulch

Cultivation i Seraping of surface

Nitrate of soda, acid phosphate, and sulphate of pot- ash were applied to plats singly. For weeds millet was used in the main line of the experiment. Soy beans. were used as @ var- iation. One plat was mulched and one merely had the weeds cut

at the surface of the ground, taking care to leaver no mulch.

66

The moisture and fertilizer contents of the soil

were determined weekly on the ends of the plats where no corn

grew, and, at longer intervals, within the corn.

No.

Plat. (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)

(16) (17)

(18)

--BETAILED OUTLINE OF EXPERIMENT-- Corn, cultivated all season; check. Corn, plat scraped. Corn, plat mulched. Corn, cultivated all season; check. Corn; millet sown at first cultivation. Corn; Millet sown when corn was two feet, high. Corn, cultivated all season; check. Corn; millet sown when corn four feet high. Corn; soy beans sown at first cultivation.

Corn, cultivated 411 season; check.

Corn; soy beans sown when corn was two feet high. Corn; soy beans sown when corn four feet high.

Corn, cultivated all season; check

Corn fertilized with Na NOg; cultivated all season, check.

Corn, e , " 5 millet sown after corn

two feet high.

Corn, no fertilizer, cultivated all season, check.

Corn,fertilized with NaNOg; millet sown when corn

) four feet high.

Corn, fertilized with acid phosphate, cultivated all

season.

(19) (20)

(21)

(22) (23)

(24)

(25) (26)

67

Corn, cultivated all season; check.

Corn, fertilized with acid phosphate; millet sown when corn two feet high.

Corn,fertilized with acid phosphate; millet sown af- ter corn four feet high.

Corn ,cultivated all season, check,

Corn, fertilized with potassium sulphate, cultivated all season.

Corn,fertilized with potassium sulphate, millet sown after corn two feet high.

Corn, cultivated all season, check.

Corn,fertilized with potassium sulphate; check; mil-

let sown after corn four feet high.

-- MAP OF pLaTs -- Scale-- 1"=027!

= MN oo

14 u 15 2 16 3 17 4 18 5 19 6 , 20 g 21 8 22 9 23 10 24 ciel 25 +2 13

26

- 69.

-- DESCRIPTION OF PLATS --

The land selected for the experiment had been in corn two or three years previously. It was gently reliine, ap peared to be fairly uniform. Slight variations, where oc- curring appeared to be eradual changes. The highest point was on the northeast part, from which it fell gently away to the southwest. There was a slight depressinn in the southeast portion. The northwest edge bordered grass land which fell away more abruptly. The extreme difference in el- evation of the. experimental ground was perhaps rifteen feet.

The plats extended from north to south in two series. The north series included plats 1 tbo 13, and the south series plats 14 to 26. The plats were 18' by 75'. 45' in the middle was occupied by corn, 15' @n each end bare or occupied by millet or soy beans. A strip of 15' was left between the series extending the whole length of the experimental ground from east to west. The corn was planted in hills three feet apart, five kernals to the hill to the better secure a uniform stand of three stalks. Thus each plat contained six rows of 16 hills each. The spaces were left at both ends rather than at one end only,to the better secure composite samples which would be com- parable to the soil in the corn.

Every third plat was reserved as a check.

-- FERTILIZERS APPLIED --

The fertilizers were applied to the whole plat as fol-

aie’ A)!

lows: * Nitrate of soda at the rate of 775 pounds per acre

to plats 14, 15, & 17; acid phosphate at the rate of 775 pounds to plats 18, 20 and 21; and sulphate of potassium at the rate of 388 pounds to plats 23, 24, and 26. The essential ingredients applied were thus approximately of nitrogen and phosphoric acid (Pp05) 125 pounds, and of potash(Kp0) 174 pounds. Calculated in the terms in which the statement of fertilizer constituents are made (Table "A", Appendix)

The nitmgen equals 554 pounds NOs

Po0s Phosphoric Acid 167 * POy

Kp0 Potash 1445 " &K

* It was intended to apply 640 pounds each of nitrate of soda and acid phosphate, and 520 pounds of sulphate of potash, but because of a change in the length of the plats an error

was made,

-- PREPARATION OF LAND --=- PLANTING AND CULTIVATION The land had been plowed in the early spring seven to eight inches deep thoroughly turning under the corn stubble. On May 17th., after three days of moderate temperature, the land was in fair condition for working, although rather moist. It was prepared,fertilized,and planted according to the plan. The continued cold weather succeeding planting and a washing rain June 18th. made replanting necessary June 22nd. It was

not necessary, however, to replant a large per cent of the corn

a a

Crowe took up some of the corn on plats 10, 11, 12 and 1, which made it necessary to again replant these plats, Gr June 18, §oy beans were sown on plat 9 at the rate of one and one half bushels per acre. The stand b’ not being good the plat was replanted with a hand planter at the same rate July 3rd.

June 18th. millet was sown at the rate of one bushel per acre on plat 5. A washing rain occurring before they were cultivated in, the sowingwas repeated June 22nd.

July 24th. soy beans were sown in plat 11, and millet on plats 6, 15, and 20.

August 6th. soy beans were sown on plat d2, and millet on 17, 21 and 26. In all cases soy beans were sown at the ‘rate of one and one half bushels per acre and millet one busk- el per acre. Where millet and soy beans were sown, the ends of the plats as well as the part in corn were occupied.

The plats were given shallow cultivation June 22nd, July 5th. and July 30th. As it was dry after this and the mulch seemed efficient it was not deemed advisable to again disturb the soil. The cultivation could only be given in one direction. The ridges between the hills in the row were cut down as needed and the plats where corn only grew were kept free from weeds. Plat 2 was frequently scraped on the surface only, taking care to leave no mulch, and plat three had about a two inch mulch of straw after becoming compacted. The plats

on which “weeds! were grown were cultivated until the millet

and soy beans were sown.

-72

-- MOISTURE DETERMINATION --

All samples for moisture and fertilizer determination were a composite of six borings taken to the depth of 7 in- ches till July 30th. After this date the surface two inches was discarded. The soil augur wasused in sampling, serving the purpose well except when the soil became extremely dry in the ‘weedy plate 5 and 9, where it was difficult to get good samples. This difficulty, however, would seem not to affect the value of the results, since if there were any variation from the proper. results it would be on the side of conservatism There would be a tndency to secure a higher moiature and per- haps also of nitrogen content on these plats than the actual amount.

Regularity was observed in the locations at which bor- ings were made. The samples in the corn were taken in the center of the square between the hills in the first, third,and fifth middles. The first borings were made in the second cross middle from each end, the second from the third, etc. At the ends the first bbring was made three feet from the corn, the second four feet, etc. Care was taken not to walk on the part, where the future borings were to be made. Where slight ridges occurred the boring was made between the furrow and ridge.

The samples were taken to the laboratory where the

moisture was determined and estimated on the basis of dry soil.

- 73 -

-- FERTILIZER ANALYSIS --

(All chemical analyses of the soil solution given in) (this thesis were made by J. A. Bizzell, Ph.D.

The fertilizer constituent was determined from the samples used for moisture estimation. Nitrogen (NO,) was de- termined for plats 1 to 17; phosphoric acid (P04) for plats 17 to 22; and potassium (K) for plats 22 to 26 inclusive.

These were estimated in parts per million (p.p.m.) dry soil.

ae Plat &2 being a check served for comparison for both P04 ®

and K!0O content.

Dat

-- WEATHER CONDITIONS --

~ 74

—

Rainfall from May lst. to September 30th., 1907.

i]

May 3rd.

"

!

4th. 6 vs 9 10 11 15 16 18 19 26

Inches

02

15

«il 2.44 oL5

022

Date

June

I

i]

25 24 25 26 29 30

23 27

inches

05 33 15

Date Inches Sept. 1 10 e 3 an” " 3 035 "4 14 : 5 «39 a 6 02 u 8 mn es 9 1.06 " 16 04 " a1 022 "ig .07" "49 Ol Mm S20 02 e BL .06 « 23 036 "24 03 Hy 327 02 " 28 06 "29 .70 ~ 20 -10 3.96

ey J

- TEMPERATURE MAY 1ST, TO SEPTEMBER 30th. -

Mean Departure from highest lowest 0 normal y May 50.3° F. -6.7° F 85 F 27° op June 62.9 -3.3 93 41 July 69.7 -0.9 89 43 August 66.6 -0.6 93 44 September 63.2 42.6 86 42

The rainfall from May 17th. when the corn was planted till September 20th. was 12.11 inches. The latter part of May and the first half of June were dry. Rain was abundant the latter half of June and fair through the first half of July. From July 1th. till in the first part of September, when numerous showers occurred, there was only one rain of consequence, that being August lst. when .91 inches fell.

The rainfall was good through September. The temperature through May and June was considerably

below normal; the remainder of the season was about normal.

-~GROWTH--

The dryness during the early crop period pevented rotting of the planted corn while the low temperature serious- ly retarded germination and growth. Through July growth was fair. In August a severe drought occurred but fair growth

was made through September.

After the second sowing of millet and soy beans was

~TE —

made, July 24th., dary weather occurred which so hindered the Needs" growth, that the experiment was seriously impaired. There was a poor stand of soy beans in all cases although they were covered a fair Gest and showed good viability in the labor- atory .- -- INJURIES SUSTAINED --

Besides the unfavorable season curtailing growth and injuring the stand, a severe wind-storm broke off some plants and cattle injured the plats as follows: 12 and 13 were so severely injured as to throw them out of the experiment;

26 was nearly as badly injured; Ip, 14 and 25 were injured less than 26; some others were slightly injured. -- HARVESTING --

The injuries above noted made the harvesting a mach more tedious process than usual in order to secure dependable results. All hills in which there was an injured stalk, and all that were clearly replant, were discarded. Record was made by rows of the number of hills harvested with 3 stalks, 2 stalks, and one stalk respectively. The rows were weighed se- parately. The “weeds" in the corn and at the ends of the plats were harvested separately. In the corncrs two representative middles at each end of the plats were harvested. At the ends the edges were discarded and the surface harvested carefully

measured.

The harvesting was done September 20th. to 24th. The

Fe

variation in time resulted from the tediousness of the task,

the lack of a fully matured plan, and unfavorable weather.

~~ EFFECT OF STAND ON THE WEIGHT OF THE STALKS --

Since there were about eight per cent of the hills which cortained but two stalks, an attempt was made to deter- mine whether estimating yield on the basis of the number of stalks was justified. Accordingly the stalks growing two on a hill where three or more such hills were in a row were care- fully weighed. These were compared with the stalks in the same row growing three in a hill. The results follow in

Table XXXVI.

- 78 w

TABLE XXVI SHOWING COMPARATIVE WEIGHTS WHERE TWO AND

THREE STALKS GREW §N THE HILL

Two Stalks Three Stalks No. Plat | No. Row | No. Hills! Wt. per) No. Hills} Wt. per

' gtalk stalk.

{ ibe. | Lbs.

a: 1 3 1.33 | 3 1.03 4 3 1.21 8 1.07

2 4 5 1.07 5 1.05 3 5 4 1.53 10 1.58 7 6 3 1.72 8 1.73 8 1 6 2.21 8 1.53 10 4 3 1.58 | 9 : 1.49 5 3 1.25 4 1.62

ala 3 3 1.33 6 1.04 14 1 3 1.37 2 L e868 5 4 1.22 10 1.35

17 4 4 1.44 12 1.28 6 3 2.21 13 1.14

18 : 4 3 164} il 1.13 4 4 } .04 | le a:

5 5 .82 10 ! we |

6 3 696 : 13 81

19 1 3 1.04 13 "68 . fF g .46 13 ; ott

5 4 1.16 11 79

6 5 1.07 11 .97

20 2 3 1.28 11 1.0¢

mere rhe

- 79

(TABLE CONTINUED) (XXVI)

No. plat} No. Row Two stalks Three stalks No. a | Wt. per} No Hills; Wt. per ; : * t | i i i 4 4 ; 83 | 12 5 86 ; f 5 3 | 96: 10 : 1.07 : , Ba fe SS | S {1,08 7 i 1.05 an a 5 7 .6 | 8 § 90 | 2 7 ave 4 é | 87 i | 4 5S | 87 f 6 § 1.01 3 5 5 75 | 6 *) 1.08 ; : 6 | 3 1.08 12 | 99 24 i Ss $148 + to ££ 4.88 i F ; : 5 | 7 # 3.95 8 1.65 | ] ‘ 2 5 S b 2.12 8 1.56 4 25 5 | 3 1.42 6 1.44 26 4 3 1.87 3 2.14 | 6 3 137 2 1.58 | 2 —_ amend

-80-

Those plats showing a larger weight per stalk where only two stalks grew were 1, 8, 11, 17, 18, and 193; those showing about the same or varying comparative weights were 2, 3, 7, 10, 14, 20, 21, 24, and 25; those showing a smaller weight where two grew in the hill were 22 and 26. Plat #22 the north end of which was markedly the poorest part of the whole ground contained five rows with three or more hills with two stalks in a hill. In four of these rows the stalks were heavier where three grew in the hill and in the other row there was but lhttle difference. 20 and £1 showed about the same weights for stalks growing under the different conditions, while 18 and 19 clearly showed an advantage, where only two stalks grew in the hill. The comparative uniformity of results in plat 22, together with the gradual change in comparative weights as the plat is approached from the west would seem to indicate a corre- lation. But a glance at 26, where two rows were weighed and where the growth was good shows a much more marked difference in weights in the other direction. Conclusions are, therefore, not warranted.

The weight per stalk where two grew in a hill averaged 3.64 per cent more than where three grew in a hill. There was considerable variation. A comparatively few hills

had but one stalk. These showed a great variation in

oa en

weight. But since the average per stalk where two grew

in a hill was not far different from where three grew, and since the number where two grew were not a large per cent of the whole, it seemed hardly worth the trouble to correct for this error. Suppose ten per cent of the hills had two stalks, weighing ten per cent more per stalk than where three grew, the error would be but one per cent. This would fall far below the range of experimental error.

Under same conditions doubtless correction should be made where the number of hills with a smaller number of stalks are any considerable per cent of the whole. The writer is informed that at one station it is estimated that a hill with two stalks is calculated to yield 80%, and one with

one stalk 42 per cent as much as where three occur.

82 -

TABLE XXVII--YIELD OF CORN FODDER BY ROWS---GREEN WEIGHT #*RATE PER 100 STALKS

No. |No. No .Stalke Wt. rate per /Average Extreme etree Plat ;Row jHarvested 100 Stalks Wt. rate} variations) varia- per 100 from tions, stalks average 1 1 15 115.0 lbs.| Ibs. % % 2 17 114.7 3 27 | 101.0 ~10.6 4 30 110.0 | 5 27 115.0 © : 6 55 124.5 113.0 ~#10.0 20.6 241 32 114.1 . 2 30 138.3 af lB 3 i 5 35 117.1 4 25 104.8 -10.4 5 35 117.4 116.9 6 36 109.7 28.7 3 L 58 144.8 ~8.8 2 27 170.4 7.3 3 2g 170.4 4 29 147.4 5 58 157.2 é 35 162.9 158.8 16.1 * The weights of each row are not here given but the rates

shown are the rates per 100 stalks. The normal number of stalks is the same in each row. This method affords an easy method of

comparison. zs Column shows number of stalks harvested, out ofapossible 48.

aux Per cent calculatbam on basis of average.

BS? x

2 North End.

5 Number of stalks out of a possible 24.

TABLE XXVII CONTINUED ‘No. No. No. Stalks ; Wt. Rate per; Average Wt.) Extreme Extrem¢ Plat} Row{ harvested 100 stalks rate per variations jvaria 100 stalks | from av- jtions. erage. r Lbs . Lbs. 7o oo i 4 l 29 148.3 2 23 158.7 +10.1 ; 3 29 124.1 13.9 4 32 154.7 : i 5 38 145.4 ; i 6 38 133.8 144.2 ; 24.0! ie 235 76.1 : : 2 24 55.2 3 3 18 38.9 -34.8 : 4 19 39.5 | 5 17 42.6 | 6 } 22 105.7 59.7 +77 01 111.9) 6 1 37 144,6 | 2 45 144.4 3 47 142.5 -4.4 4 39 157.7 5 48 146.9 6 33 158.3 149.1 +6.2 10.6 "7 1 33 151.6 2 31 151.6 Bj 37 138.5 -21.9

- 84 -

*eStalke harvested out ef a possible 24.

Wr . #Only,middle four rows of the north part taken.

TABLE XXVII CONTINUED No. No. No. Stalks Wt. Rate per Average Wt. Extreme Extreme Plat Row Harvested 100 stalks rate per Variations Varia- 100 stalks from av- tions. erage tt ha 7 4 35 166.4 . ? 7” 5 32 162.8 6 30 172.6 187.28 +9.7 21.6 8 1 36 175.7 2 40 163.7 Yo) 45 176.7 4 34 156.6 " 5 37 199.3 +24.6 6 34 88.2 160.0 -44.9 69.5 29 1 HLS 80.4 +352.9 2 25 78.35 vo) 23 62.0 4 24 47.9 5 24 52.1 6 19 42.1 60.5 -30.4 63.3 10 1 32 143.8 2 42 141.1 3 36 128.3 -11.9 4 33 150.8 : 5 18 151.4 | q 6 26 156.7 al +8.9 ene!

ae:

TABLE XXVII

CONTINUED

No.

Plat Row Harvested 100 Stalks

il

14

15

16

ao non -& A o #&F AF YD FP OO ao FF AB DN YF OD oO FF A YD KF

41

et yen Maen aaa * RPE See Chr oe EIT Lie Ar vi BA CA ITAL SAR ee TAL

128.4 107.5 111.5 119.9 112.9

93.7 131.2 116.4 125.0 132.6 132.2 1353.3 137.0 134.4 141.3 139.6 134.1 130.9 129.1 123.9 LI7s7

a Lee aC Ma ARES CN a POLI ne habe EPA a bie neat Fashanst ts To Ie Ze

rate per variations Varia- 100 stalks from av- tions erage mm 70" re nag ne ie F $14.3 112.3 -16.6 30.9 -9 e 3 128.4 +3.8 13.1 +#2.5 136.2 -3.9 6.4 4+11.7

ORE ATA IO Pn EU IEEE PE le al MH

No. No. Stalks Wt. Rate per Average Wt. Extreme

i A a PD dan ¥ ar.

Extreme

No.

Plat Row harvested 100 stalks

2 86a

TABLE XXVII

CONTINUED — |

No. No. Stalks Wt. Rate per Average Wt. Extreme Extrem

16

dd

18

19

o am £ FW DO KY @ oOo FF AF UN YF oh oo FF RW DUE lel

34 41 44 43 46 46 44 47 45 39 48 44 44 40 45 45 45 35 40 41 43

rate per varia- varia- 100 stalks tions from tions | average

ne es we we 100.6

92.0 115.6 ~20.4 52.1 | 93.0 -24.9 148.1 +19.6

129.9 131.2 ° 125.5 115.0 123.8 44.5 119.2 $5505

91.7

90.9

75.0 -16.1

76.2

83.5 89.4 39.4 72.8

67.8 -21.2

92.9

97.5

86.0

99.4

86.1: +15.4 36.6

No.

No. No- Stalks Wt. Rate per Average Wt. Extreme

“EP

TABLE XXVII CONTINUED

Plat Row harvested 100 stalks

20

21

22

25

a fb Ho oP WAY HY OO Ph WY YP OT Ff wD PH

90.8 101.9 107.0

85.7 104.9 131.8 114.4 114.4 105.8

94.2 103.7

92.1

88.2

81.2

779

98.5

92.0 100.0 119.3 144.8 141.7

rate per 100 stalks

103.2

104.1

89.6

ne Soom ay

Extreme Variations varia- from av- tions erage

ease mg ys ye

-17 oH

$27.1 44.5

+9.9 °

“11,5 21.4

eat

$11.6 Le 7

$9.4

No.

24

26

Pecaeais tes

TABLE XXVII

Pe ae

CONTINUED

No. No stalks Wt. rate per Average Wt. EXtreme

aa fF FW DO FH hh oO fF A YD KF @ ao FF FF YD FP OO HO

26 52 36 36 37 38 35 350 35 25 26 24 28 25 25 15 28 19 15 14 12

Plat Row harvested 100 stalks

137.5 109.4 141.0 161.8 171.6 167.3 162.1 166.6 167.4 176.1 121.2 143.7 142.9 114.0 108.7 135.0 126.8 145.0 116.6 144.6 137.5

_seicrnesimethoatmianmsmainth anata td BN

rate per 100 stalks

132.3

166.1

134.4

134.2

variations from av- erage

+51.0

-19.2

+8.0 -13.1

Extreme varia- tions

26.7

5.9

50.2

21.1

= BO

After eliminating the first and sixth rows from the north ends of plats 5 and 9, the north ends only were taken, since the data from the south ends were not depend- able due to injuries sustaine@. The variation was as fol- lows: For plat 5, Minimum 11.6%, maximum 25%, and extreme variation 36.6%; for plat 9, minimum 20.3%, maximum 30%, and extreme variation 50.3%.

The table shows an extreme variation in green weight of stalks between the rows of the same plat from 5.9 per cent in plat 24, to 111.9 per cent in plat 5. E- liminating plats 5 and 9, the maximum extreme is,65.9%, oc- curring in plat 8, and the average variation is about 28 per cent. The number of stalks harvested in the row seems to have little influrnce in the variation.

Rows 1 and 6 of plat 5 being on the edges of the plats, where conditions for growth were better, should clearly not be counted in final yielde. To secure com- parable results rows 1 and 6 of plat 9 were also eliminatdd. Row 6, plat 8, being next to plat 9, is clearly not repre- sentative. Rows 5 and 6, plat 16, and row 1 plat 17 were markedly poor; but row 4 plat 16 and row 2 plat 17 were

TOE markedly good. rhe pierdd indicate that the south series beginning with plat 14 improved in productiveness to about the middle of plat 15, from whence a gradual reduction is shown till the border between plats 16 and 17 is reached.

A few rows beyond thie show an increase, after which there

ge AS

is a decided fall. No part, however, was eliminated in

calculating yields except in plats 5 and 9, as above stated. The variability noted throughout the table, and

especially in this apparently uniform land from plats 14

to £0 inclusive, where we believe no one not seeing the goow-

ing crop would suspect the lack of uniformity, indicates

the extreme caution which should be exercised in conduct-

ing plat experiments.

--DETERMINATION OF DRY MATTER--

For the determinationof dry matter representative samples were taken.Of the corn, two hills of three stalks each seks eros plats 2,3,5, and 10. Of millet and soy beans composite samples were taken; millet from plats 5 and 6, and soy beans from plats 9 and 11. The samples, While rather

small for the purpose are believed to give fairly approxi-

mate results.

- 91 -

Ce tmeeinee 2k, @ eH,

Ce ee

Pesce ee wearer = saaeomceae

TABLE XXVIII SHOWING DRY MATTER SS”

No. Plat ___ Kind of Crop Dry Matter | 2 Corn 21.42 3 v 21.58 5 " 24.69 5 Millet 33.71 6 " 17.50 :

Soy beans

9 Weeds & Grass 25.59 10 Corn 19.99 Lo Soy Beans 21,02 i

In Table XXIX, which follows, the weights in dry matter are given. For the plats where dry matter was deter- mined, the per cents shown in the above table were used in correcting from green weight. For the remaining corn plats except plats 9 and 11, the average of plats 2, 3, and 10 were taken. Plat 9 was calculated the same as plat 5, and plat 11, the same as plat 10. The remaining millet was cal- culated the same as the millet in plat 6.

In the column, "Production capacity of corn" the weights for the check plats are the actual yields. The in- termediate figures given refer to what the corresponding plat presumably would have yielded had it been treated as a check.

It is assumed that the change in productive capacity of the

eae

soil was gradual between the check plats. The calcu-

lation is made by taking one third of the difference be-

tween the consecutive check plats and adding or subtracting according to the trend of the variation. The productive capacity for plat 11 was calculated on the assumption that

the same variationpccurring between check plats 7 and 10 continued through plat 11; and plat 15 was similarly calcu- lated from check plats 16 and 19. This method would appear less reliable than where a check plat is in each side of the

plat for which the correction is made.

rn Ce eeemmamtial

r b

No. Plat Stand corn harvested A! 52.43 2 66.32 3 68.06 4 65.97 “#5 85.42 6 86.46 4 69.44 8 78.82 “9 94.44 10 65.97 oe 56.94 12 13 14 65.28 15 96.18 16 86.81 17 94.10 18 90.63 19 86.46 20 84.72 21 76.74 22 70.83 23 66.32

Per cent

aoe Ss

Variation

between rows

13.1

6.4 32.1 44.5 39.4 36.6 44.5 21.4 24.7

26.7

TABLE XXIX! YIELD-CORN, MILLET AND SOY BEANS.---

5 aaa

Production Capacity of corn

Lb. 3522 3800 4079: 4357 4497 4637 4776 4581 4386 4190 3995

3828 3522 3216 2910 2605 2671 2737 2803 3253

wo

TABLE XXIX: YIELD —<

2 mea ena

Per een

No. Plat Stand corn harvested 24 72.22 25 51.74 26 36.11

= Od =

CORN, MILLET and SOY BEANS '

Variation between "rows

Zo 5.9

50.2 ell

Production capacity of corn

tbe, 3663

4093

* The four middle rows of the north half only taken,as

South end was damaged by cattle.

serves geet commer

Sree,

TABLE XXIX : YIELD -- CORN, MILLET

t

sia eaiiadi sitive b t

{

Oo Oo YE DO a fF A ND FF

rae

BPP FP HY Pe YF HY FP orton w wove Oo

--Yield, Rate per acre-=

Corn Millet In Corn Ends

1609 3932 4999

4528 *180 2026

4913 191 772

3922 4155 L228 2182

3522 3735 negligible 369 2722

2605

AND SOY BEAN

Soy Beans In Corn

hb,

2090

554

S

Ends ta,

3700

894

eG Ve

TABLE XXIX : YIELD -= CORN, MILLET AND SOY BEANS

Ns -- Yield, Rate per acre--

> _ ;

i

No. Plat Corn Millet Soy Beans

In Corn Ends In corn Ends

t ; mu e his uly caren c7 7 er nie eee 21 3163 Negligible 740 22 2803 23 3991 % 310 24 5069 201 2665 25 4093 26 4075 Negligible 1156 é

}

oe ww

or na ws

TABLE XXIX: YIELD -- CORN, MILLET AND SOY BEANS Total exclud- Increase + Increase + ing ends. or or Decrease - Decpease - of total of corn a 3522 — oheck check 3643 -157 4952 £875 4357 check check 5321 #1044 -2888 4708 + 71 - 109 4776 check check 5104 #523 +332 4235 -151 ~ -2241 4190 check check 3844 -151 -685 3922 +286 4377 +549 +527 3522 check check 3735 $519 2722 one 2605 check chech 3362 +691 #472 3163 etre 2803 check check

caepecanta etme ne Take yee Ee

- 97 -

.

a ee

TABLE XXIX: YIELD -- CORN, MILLET AND SOY BEANS

semanas A ee ere aren ne Reamer Se Plaf Total exclud- y No. ing ends “Ph,

25 3991 | 24 5270 25 4093 * 96 40%5

~ 98 =

Nestor daar 0"

Increase + or

Decrease -

of total

neha tah a 6 eawowiaee MT, Sm agenNnaRe

Increase + or Decrease — of corn

Ota. +758

+1406

check

eee ee ey eee

ee reremmmounnsmre vom

en Ea wee oa

eae aboane ARES

po

TABLE XXX

o oa Xr’ owas fF WA NY HF

Do YF Be EF BF YF Ee YF YP BF 0 0 ON oO oO Fk A YY OO

= 69 <

tracer

SHOWING AVERAGE MOISTURE CONTENT?FOR DIFFERENT PERIODS. PER CENT DRY SOIL (DEDUCED FROM TABLE "A" APPENDIX)

July Sth., 16th,

24th. & 30th. Ends

d,

22.6 21.5 26.0 20.1 17.9 20.4 18.5 19.4 14.8 16.5 15.7 14.4 15.9 24.6 24.4 23.2 22.45 4 Aied 20.7 20.0

ce a nner Ried Hawn ET ae

Aug. 5th, 19th, 26th, &Sept.16

Ends. 2a 4

21.1 18.2 25.0 18.2

9.8 17.0 La? 17.4 10.0 15.2 13.0 13.0 14.7 23.1 21.5 22.5 21.5 20.4 19.9 17.4

In Corh,.

ie

18.0 15.0 17.9 12

9.7 13.1 14.1 14.7

9.3, 12.3 226 146 13.7 19.0 16.9 17.5 15.4 15.3 16.7 14.6

ee A EN ee ae

eecmar e

- 100 -

| TABLE XXX SHOWING AVERAGE MOISTURE CONTENT FOR DIFFSRENT _ | PERIODS, PER CENT DRY SOIL (DEDUCED FROM TABLE "A" APPENDIX) ; “ IR te aR wees Dikie seaintinlel: Sade- eebictie

migenens ar RONEN 1 cuewnreememe 2 ee | Se tial a aR Ne ne es

' No. July 9th. 16th. Aug. Sth, 19th, ‘26th & Sept. 1

; Plat e4th. & 30th. Ends - . Im Corn.

pEerem spe ae Sova a “ : aa ; ee Benda

i 21 20.9 19.6 14.5 22 19.6 17.9 14.6 235 21.0 1945 14.6 24 20.5 16.0 12.9 25 19.3 17.5 13.2 26 19 ~l 16.5 lee

- 101 -

be acento fe sees ore

“TABLE XXX SHOWING AVERAGE MOISTURE CONTENT FOR DIFFERENT ' PERIODS, PER CENT DRY SOIL (DEDUCED FROM TABLE "A" APPENDIX)

ech? mt ee mtg ne

i

August 19th and 26th

No. Difference Aor, Emds. 5 In Corn Diff. | Plat , Io 1 1 i Si 19.8 14.9 4.9 2 3.2 16.1 11.8 4.3 3 ere 24.2 15.8 10.4 4 4.5 16.9 10.3 6.6 5 Cet 5.9 5.7 0.2 6 3.9 15.1 9.7 5.4 4 3.6 16.3 11.8 ° 6.1 8 ed 16.6 12.0 4.6 9 0.7 7. 6.2 0.9 ' 10 2.9 14.6 10.5 43 i 1.5 12.4 9.7 2.7 12 Let 12,5 13.4 =0,9 13 1,0 14.3 18:2 isi 14 4.1 21.3 15.8 5.5 * 6 4.4 18.0 13.3 4.9 16 5.0 21.0 13.9 al 6.1 19.6 12.1 245 | 18 5.1 16.7 ys 7.2 | 19 3.2 18.3 137 4.6 20

2.8 14.4 11.5 2.9

mPa oR A tent gee

eR ee

3 € aecinmempee. +

ame,

“TT RABLE XXX

evemeneanemaryin pence

102 -

SHOWING AVERAVE MOISTURE CONTENT FOR DIFFERENT

PERIODS, PER CENT DRY SOIL SUREBORD FROM TABLE "A" siscsaowieic

nd

Difference ree

re Teme nice earns Aen some ee

" August 19th and 26th —

Ends | In Gorm Dift. a , 6

18.3 11.0 7.3 16.5 11.6 4.9 18.3 11.2 7a 12.5 9.0 3.5 16.3 10.5 5.8 15.6 9.5 Bt

Se See ree saci ere ee), gin a ematammnatin ce

iggihemae s+

~ 103 -

: + tore.

+ TABLE XXXI SHOWING DIFFERENCES IN MOISTURE CONTENT OF SOIL FOR DIFFERENT PERIODS, BETWEEN THE ENDS, AND WHEN CORN GREW | ALSO THE VARIATIONS IN YIELDS No. August 5, 19, 26 August 19 Increase+ Plat and Sept. 16 and 26th. or Caleulated Calculated Decrease - i from checks Found from checks Found eae I 2 peters ae F, sald -_ bette 2 3.6 ase 5.5 4.3 -1.2 3 4.1 Tad oid 10.4 4.3 4 4.5 6.6 | 5 4.2 0.1 6.1 0.2 -5.9 an: 3.9 3.9 5.6 5.4 = 22 . & 3.6 5.1 | 8 3.4 ” Beh 4.8 4.6 - 2 9 B.e ~ ie 4.5 (0.9 -3.6 “10 2.9 4.1 11 225 1.5 Sel Ze - 4 12 1.7 -1.1 Pad -0.9 -3.0 13 1.0 1.1 14 4.1 5.5 15 4.4 4.7 ' 16 5.0 Det 17 4.4 6st 845 7.5 41.2 18 3.8 5.1 5.5 7<2 +1.7 19 Sek 4.6 20 3.2 2.8 4.7 249 -1.8

i, piaiesesis GiiaicteGiada:” oy

ca ae nance

egemtm me

Leone

- 104 -

Pema TA AS ee oP cceareeneemameniceviete

rPABLE XXXI SHOWING DIFFERENCES IN MOISTURE CONTENT OF SOIt,

FOR DIFFERENT PERIODS, BETWEEN THE ENDS, AND WHEN CORN GREW

ALSO THE VARIATIONS IN YIELDS ea, a, as. Sa, Gh. el Sat eee Sate aeeGs taste No Aupust 5, 19, 26 August 19 Increase Plat and Sept. 16 and 26th. or * Calculated Found Calculated Decrease from checks from checks Found = Bee gaai a ck est 21 * Sek 5.1 4.8 Ted -2.5 22 3.5 4.9 | 25 3.6 4.9 5.2 7.1 $1.9 24 3.9 Sek 5.5 3.5 -2.0 25 4.3 5.8» 26 3.6 6.1 2 oo Na a ned ih Pit ne Teta ele Sa et ey Ue on eat il Eta se: % In this calculation it is assumed that changes occur

gradually between the checks. To illustrate the method take plat #2. One third the difference petween checks 1 and 4 added to # 1 gives 3.6, which is supposed to be the dif

ference between the moisture between the ends and in corn had

Do beegreated as a check.

- 105 -

ae ene aera ser

TABLE XXXI SHOWING DIFFERENCES IN MOISTURE CONTENT OF SOIL '

FOR DIFFERENT PERIODS, BETWEEN THE ENDS, AND WHEN CORN GREW ALSO THE VARIATIONS IN YIELDS "No. ~)~)”~*«é‘<i er Gent Stand =~—CODrry Matter Plat Increase + or decrease - Corn Total x 52.493 check 2 66.52 -157 3 68.06 +873 4 65.97 check 5 85.42 -2888 +1044 6 86.46 - 109 \ h 71 6 69.44 check 8 78.82 f 332 + 523 9 94,44 -2241 - 151 10 65.97 check 11 56.94 - 685 -151 ig 13 14 65.28 : 15 96.18 ¢ 327 + 549 16 86.81 check 17 94.10 +519 18 90.63 - 188 19 86.46 check

84.72 +472 Poet

[we] [o)

. eine]

Ty ek oe ENE LE TE

A ddan &

apres

106 -

TABLE XXXI SHOWING DIFFERENCES IN MOISTURE CONTENT OF SOIL

FOR DIFFERENT PERIODS, BETWEEN THE ENDS, AND WHEN CORN GREW

malt dnt a CRRA GAL ene a garantie

ALSO THE VARIATIONS IN YIELDS

ce rome fae sh

Norman 7

4 é i 5 ? 3 } med i i

No. Per Cent Stand Dry Matter Plat Increase + or decrease -

Corn Total

mL 76.74 +426

22 70.83 check

23 66.52 +758

24 72.22 +1406 +1607

25 51.74 check

26 36.11

- 107 -

Reese - Mmintamearealennmciie = erent ee

'RABLE XXXII SHOWING AVERAVE FERTILIZER CONTENT FOR DIFFER- | ENT PERIODS--PARTS PER MILLION OF DRY SOIL (DEDUCED FROM i TABLE "A" ener

Dee = ECE ee eR PR 8 Ant Se eB IO A

“No. duly 9, | Aug. Aug. Plat 16,24,30. 5, 9,26, & Sep. 16. 19 & 26 Ends Ends In Corn Ends In Corn oo NOg CONOR | NOs NOs NOz 1 80.1 90.4 53.0. 70.8 16.7 2 97.1 90.6 Tiss 52.8 52.5 3 68.2 85.7 29.5 97.5 23.5 4 97.0 123.7 24.3 87.9 16.5 5 48.5 2.0 3.6 1s? eS 6 «86.0 60.5 1741 50.6 gp BOs 7 81.8 93.2 29.6 66.9 9.6 8 85.7 89.4 33.7 88.8 24.8 9 63.4 5.9 5.8 2.6 5.0 10 56.0 89.5 24.8 59.9 22.8 11 51.8 77.9 26.2 55.0 27.2 . 36 52.4 58.4 55.4 61.8 62.1 (1s 57.3 96.8 36.1 75.9 35.6 | 14 200.1 77 205.6 157.8 143.7 | 15 240.6 229.8 166.7 150.9 148.5 / 16 140.2 160.4 Lig, 127.5 80.1 17 208.0 254.8 181.2 174.3 166.3 PO, PO, PO, PO, PO, 18 8.9 9.3 8.3 10.2 8.6 / 19 8.2 8.4 ‘845 9.3 8.5

Re ao oer NANCE ET ie

oa

Seem

- 108 -

“TABLE XXXII SHOWING AVERAGE FERTILIZER CONTENT FOR DIFFER- _ ENT PERIODS--PARTS PER MILLION OF DRY SOIL (DEDUCED FROM TABLE "A" APPENDIX )

“ N O. July 9 _ -_ Aug ‘ . Aug ‘ — Plat 16, 24, 30 5, 9,26, & Sep. 16 19 & 286 Ends Ends In Corn Ends In Corn ee Bog ends “Po, ; - Py — PO, sa 29 sii 20 ; 8.6 8.4 8.2 8.2 Biel | 21 7.9 8.9 8.8 8.1 7.6 22 7.95 8.8 Tat 9.6 7.0 aes is fe a iis 22 9.1 6.8 5.7 5.1 . 3.9 25 8.5 10.4 Tea 9.6 5.7 \ 24 8.7 7.6 7.2 6.0 5.5 ' 86 10.8 8.4 Bet 6.8 4.7

26 12.9 9.8 1047 10.9 10.9

Patan

- 109 -

DISCUSSION OF RESULTS

First sowing of "Weeds"

Plat 5 Yield

On Plat #5 millet was sown at the first cul- tivation June 18th,

TABLE XXXIII THE RATE OF YIELD PER ACRE OF BOTH CORN FODDER”

AND MILLET ee: ee "Weeds" Corn &"Weeds" WeMeers Seem ey Tg eam AS ANE AUR ig eke bat End . i tt In Corn In Corn Green Dry Green Dry Green Dry. Green Dry

Wt. Wt. Wt. Wt. Wt. Wt. “Wt. Wt. yy “tie Aba Ba the Bh the,

Normal

Productive 21413 4497 14829 4999

Capacity

Yield 6515 1609 14829 4999 11011 8932 17526 5541

Increase + or -3887 +1044 Decrease -

sees pater +. 2 NRT eg rer te ot mer SO neo aati tate mee AF Sirttne Teck aga TF Sea eset s

Calculated on the basis of green weight the total yield of corn fodder and millet was 3887 pounds less than the productive capacity of the green corn fodder; but calculated on the basis of dry matter the yield was 1044 pounds greater. The percentage of dry matter in the

YJ

we corn was 21% while in the millet was 35.71%.

- 110 -

TABLE XXXIV MOISTURE, CALCULATED ON THE BASIS OF DRY SOIL

PLAT 5 : Ends In Corn oe, Se : i

July 9,16,24 Aug. 5,19,26 Aug. 19 Aug. 5,19, Au Calculated 30. & Sep. 16 & 26 26 &Sep {6 19 oy

from % va fo 0 0 checks 19.6 18.0 16.7 13.8 10.6 Actual 17.9 9.8 5.9 9.7 5.7

The decrease in the moisture content if marked. The millet grew rapidly during the early period of growth. When it is remembered that the moisture in the checks was too ie nue of the time for best results, the poverty of

moisture in plat 5 is emphasized.

TABLE XXXV NITROGEN (NOz) PARTS PER MILLION (P.P.M.)

DRY SOIL (AVERAGE FOR DATES GIVEN ) PLAT 5 Ends” ; jin Corn July 9, 16 Aug. 5, 19,26 Aug. 19 Aug. 5,19 Aug .9 24” 2°30” & Sept. 16 R26 26 RSepl6 = & BE

P.Dell. babel. p.p.m. p.pti. p.p.m Calculated

from 92.0 113.6 80.9 26,1 14,2

checks

Actual 48.5 2.0 1.7 326 Ber

~ Ti =

There is shown a speedy reduction of nitrogen both on the ends and in the corn to a point which would

seem to seriously limit if not prohibit plant growth.

XXXVI COMPARISON OF THE REDUCTION OF MOISTURE AND NOz, PLAT 5

. Ends In Corn

|| July 9,16 Aug. 5,19,26 Aug.19 Aug.5,19 Aug,

og 50 A Sep. 16 & 26 «286 &Sepk6 19 &26 Foisture z ze ze Normal cal-

culated 19.6 18.0 16.7 13.8 10.6 from checks .

Actual Amt. 17.9 9.8 5.9 9.7 Def Nitrogen p.p.m. p.p.m. pP.p.m. p.p.mM. p.p.m. Normal Amt.

calculated 92.0 113.6 80.9 26.1 14.2 from checks

Actual Amt. 48.5 2.0 diet 5.6 2.2

The summarized comparison shows a much more speea- y diminuition of the nitrogen than of the moisture. The nitrogen contents lowers with the moisture not only in this plat, but holds true on the part of all plats whene crops were grown. (See Table "A" Appendix) But the ni- trogen lowers relatively much more rapidly when a large crop of “weeds" were grown. It is interesting to note that

the nitrogen content of the corn grown on this plat was only

- 118 - -84 per cent, ae acathy,

PLAT

#9 YIELD

On Plat #9 soy beans were sown at the first culti- woe

vation June 18th. and, later replanted July Sth. The stand

was not sufficient to prevent the growth of weeds and

grass. The soy beans, perhaps, constituted half of the

weeds harvested. No nodules were found on the roots.

WP ae a Sia yeneeld aha

ae ee

‘TABLE XXXVII THE RATE OF YIELD PER ACRE OF BOTH CORN FODDER

AND "WEEDS" Corn "Weeds" Corn & "Weeds" alte aensat y . End. In Corn Corn & "Weeds" Green Dry Green Dry Green Dry Green Dry Wt. Wt. Wt. Wt. Wt. Wt. We. wt. ade ee Bie Ee Oy he tha hoe Productive Capacity 20886 4386 14461 3700 Actual 8689 2145 14461 3700 8167 2090 16856 4235 Increaset or ~4030 -151 Decrease-

Calculated on the basis of green weight the total

yield of corn fodder and "weeds" was 4030 pounds less on

than the productive capacity of green corn fodder.

The basis of dry matter the yield was 151 pounds less.

Or,to state it differently, the

dry matter in "weeds

production of 2090 pounds of

" reduced this yield of dry matter

- 113 -

in corn fodder 2241 pounds.

mw

ment of results, green weight would have been entirely

Here as in plat 5 the state-

misleading.

TABLE XXXVIII MOISTURE CALCULATED ON THE BASIS OF DRY SOIL,

PLAT 9 Ends fi In Corn July 9,16,24 Aug. 5,19,26 Aur. i9"4ug. 5,19, Aue. & 30 & Sep. 16 & 26 26, &Sep.16 19&26 | Ve Qf - fe qt t ; Calculated from 17.2 16.0 15.2 12.9 10.8 , checks Actual 14.8 10.0 Tau 943 6.2

The reduction in the soil moisture as compared with the checks whene corn only grew was very marked even early in the season. It was evident during the greater part of the season that the moisture content was too low for normal growth.

TABLE XXXIX NITROGEN(NOZ) CALCULATED PARTS PER MILLION (P.P.M.) DRY SOIL (AVERAGE FOR DATES GIVEN), PLAT 9

July 9,16 Aug. 5,19,26 Aug. 19 Aug. 5,19, Aug, 19 D4, &'30 & Sep. 16 & 286 26& Sep.16 & 26

p.p-m. ppm. p.p.m. p.-p.m. p.p.m.

Calculated 64.6 90.7 62,2 26.4 1841 from checks

Actual 63.4

- 114 -

Here, as in plat 5 is shown a much more rapid

diminuition of nitrates than occurs in the checks,

.

TABLE XXXX COMPARISON OF THE REDUCTION OF MOISTURE AND

NITROGEN PLAT 9 Ends In Gorn July 9,16 Aug. 5,19,26 Aug. 19 Aug. wy Le Aug.19 24 & 30 & Sep.16 & 26 26 & Seplé &26 I qe I vi q Moisture Calculated 17432 16.0 15,2 12.9 10.8 from checks Actual 14.8 10,0 Toll 9.35 602

Nitrates NOg Calculated 64.6 90.7 62,2 26.4 1662 from checks

Actual 63.4 5.9 265 5.8 5.0

Here as in Plat 5 a much more rapdd reduction

of nitrates occurs than of moisture.

SECOND SOWING OF "WEEDS"

A drought succeeded the sowing of the second crop of "weeds" July 24th., which seriously injured this

part of the experiment. Millet was sown on plats 6,15,

20 and 24, and soy beans on Plat 11. The soy beans in

the corn grew as tall or taller than at the ends of the

plats.

- 115 -

TABLE XXXXI SHOWING RESULTS OF SECOND SOWING OF "WEEDS PRODUCTIVE CAPACITY CALCULATED FROM CHECKS. RESULTS IN

DRY MATTER No. Productive Yield in Corn Increases*Decreaset Plat Capacity Corn Millet Soy Beans Corn Total Corn |

lbs. lbs. lbs. lbs. as lbs, 6 4637 4528 180 -109 +71 15 3828 4155 222 +527 +549 20 267 1 3143 219 +472 +691 24 3663 5069 201 +1416 +1607 11 3995 3310 534 -685 -151

TABLE XXXXII SHOWING RESULTS OF SECOND SOWING OF WEEDS. THE PRODUCTIVE CAPACITY CALCULATED FROM CHECKS, CORRECTED FOR EFFECT |

OF FERTILIZER. RESULTS GIVEN IN DRY MATTER. | No. Productive Yield in corn Increase WaDecrease (- Plat Capacity corn Millet Soy beans Corn Total corn lbs. ~ Eke, lbs. lbs. ‘Ibs. __Ibs 6 | 4637 4528 180 -109 +71 15 3922 4155 222 +233 4455 20 2483 3143 219 +660 +879 24 4421 5069 201 +648 +849

um 3995 3310 534 -685 EBL

- 116 -

In Table XXXXI the comparison is made with the productive eapacity calculated from the checks. The method, however, is not logically correct fur plats 15, 20, and 24 since these were fertilized with sodium nitrate, acid phosphate and potassium sulphate respective- ly. Plats 14, 18, and 23, were fertilized to correspond with the above plats in the order named to dertermine the effect of fertilizers. An attempt was made to correct the calculated productive capacity from the checks by correcting for the effect of fertilizer. (TABLE XXXXII) The actual yield of 14 was taken for conpev deen gat plat EB.

The number for comparison with plat 20 is secured by subtracting 188 pounds, which is the loss apparently due to the acid phosphate in plat 18, from the normal productive capacity (26714 - 188# = 2443#) .

The number for comparison with plat 24 is se- cured by adding 758 pounds which is the gain apparently due to the potassium sulphate in Plat 23, to the normal productive capacity (36634 + 758# = 44217)

The results from the two methods are about the same except by the latter method (Table Xxx) the increase in plat 24 is less marked.

When millet was sown in plats 15, 20 and 24,

there was an increase in corn fodder, Plat 6 showed a

117 -

decrease in corn but an increase in the total weight. Where soy beans were sown on plat 11, the total showed a decrease,

It should be remembered that while the yield of weeds was small, young plants have a relativety large proportion of roots, and a smaller proportion of that ebove ground can be harvested. If this is considered probably every plat showed an increase in total yield.

But was the increase due to any Uawteipidiont effect from the light growth of "weeds", to the ealculated productive capacity being too small! It will bg very diffichit to determine the effect of a light growth of weeds in plat experiments since the weight of a light growth may easily come within the range of experimental error.

THIRD SOWING OF "WEEDS"

The third sowing of "weeds" made August 6th. failed to grow sufficiently for harvesting except plat 8. The millet gave a yield of 191 pounds dry weight (Table XXIX). Compared with the productive capacity the corn gave an increase of 332 pounds of corn alone, making a total increase of 523 pounds. Thisis in line with the re- sults obkained from the second sowing of "weeds".

EFFECT OF MULCHING

Plat #3 was mulched both in the corn and in the

= 116 =

ends. Weeds were not permitted to grow. The increase in dry matter over the normal productive capacity cal-

culated from the checks was 87% pounds.

“TABLE XXXXIII COMPARING THE YOISTURE AND NOz CONTENT

Ends In Gorn

July 9,16, Aug. 6,19, Aug. 19 Aug. 5,19, Aug.] 24 & 30 ee. & Sep.16 & 26 26, Sep.16 @ BE |

% I % Vi a Moisture Normal Calculated 20.9 192 17.9 1g.1 1148 from checks Actual 26.0 2000 24.2 17.9 1318 No @ om. p»p eM» e oM. e eM. ° em Normal Calculated 85.7 LOD w® 76.5 5569 16:5 from check Actual 68.2 85.7 97.5 29.5 A Dia

On the ends of the mulched plat the moisture ran considerably higher than on the checks. In the corn during

the dry weather, the moisture content ran nearly as low as

the calculated normal. There was thus considerably more

water used by the plants, which was reflected in the lar-

ger yield, During the most trying period of the drought

the corn on this plat seemed to suffer nearly as severely

as on any of the plats. The nitrogen content was greatly

lowered, as well as the moisture.

It was noted in the early season during a wet and rather cool period that the plants on this plat were growing more wagrreeky than, the cultivated plats near it. Presumably the soil under the mulch was cooler

and contained less air than where there was no covering.

EFFECT OF SCRAPING Plat © was not cultivated after planting but the weeds were prevented from growing by cutting them off at the surface of the ground, taking care to leave no mulch. The yield of corn fodder, dry matter, was LB7

pounds less than normal as calculated from checks.

“TABLE XXXXIV SHOWING THE MOISTURE AND NOg CONTENT OF PLAT 2

nine enhae

Ends In Corn July 9,16,24 Aug. 5,19,26 Aug. 19 Aug.5,19 Aug.19 & 350 & Sep. 16 & 26 26 & Sepié & 26 Ie I Ip % 4.

Moisture Normal 21.8 20a 18.8 16.6 13.4 Calculated from checks Actual 2143 18.2 16.1 15.0 11.8 NOz r i f Normal P»-peM. p.-p-m. e ie: e e « ° Pep mM.

from checks

Actual eo? .1 O06 52.8 TiLaB |

- 120 -

The moisture was somewhat lower than the checks. The nitrogen on the ends was not materially different except during the drought (Column Aug. 19 & 26) when it materially lowered. The nitrogen where the corn grew was much higher than in the checks. Since this can not be accounted for by a sufficiently decreased yield, what is the explanation? It is usually supposed that cultivation favors nitrification. Was nitrification more rapid in this plat than in the checks, or were more nitrates brought up from an accumulated reserve below? The nitBogen con- tent of the soil, Sept. 16, when considerable rain had fallen gives some indication that this latter view may at least partially account for the phenomenon.

(See Table A, Appendix)

In the early part of the season the growth on the scraped plat appeared to be considerably poorer than on the checks, yet the final yield was but 157 pounds ,or 4.1% lese than the calculated normal yield. It isfprobable that the calculated normal yield is slightly low, but even then there is not the diminuition in final yield that was indicated by the early growth. It would thus seem possible that on the scraped plat the moisture available was made

more efficient by an abundance of available nitrogen in

the soil.

~

= 121. =

-- COMPARISON OF MULCHED AND SCRAPED PLATS --

TABLE XXXXV_ SHOWING DEPARTURE FROM NORMAL AS CALCULATED FROM

CHECKS, IN YIELD, AND MOISTURE, AND NITROGEN (NOs) content in

No. Plat ment

3 Kulehed 2 Scraped

3 Mulched

Treat- Moisture Jul.9,16 Au

2 Scraped Moisture - 0.5

SOIL

B n d

& Nitro- 24 & 30 26,Sep.16 gen % Is

— 1.9

" rae i Bo P-D.Mm. ppm.

NOz so OS -10.9

" te 6 «15.8

8

In Corn

&- 5,19 Aug. 19 Aug.5,19 Aug.19

& 26 26,Sepl6 & 26 Yield =A Is g. #bs “267 ~1.6 -1.6 -157 46.3 42.8 +8.0 +873 P Mm. p.p.m. p.p.m.

“23.7 +28.9 $35.9

421.0 -4.4 +6.8

There was a greater difference between the moisture

of the ends and in the corn in the mulched than in the

scraped plats.

are evaporation and capillarity.

dant in the scraped than in the mulched plat.

There are many varying factors, among which

The NOw where corn was growing, is much more abun-

Was this

due to the moisture in the soil not being sufficient to per-

mit sufficient growth to use the availabié nitrogen?

lowered with the moisture.

5 and 9 where the first sowing of "weeds" was made.

-- VARIATIONS IN FERTILIZER CONSTITUENTS --

(See Table XXX7JZ )

The nitrates varied greatly.

In general they

This was very marked in plats

In these

- 122 -

plats the soluble nitrogen lowered much more rapiddly than did the moisture. While the moisture soon ran so low in these plats as to limit plant growth it is a ques- tion whether the poverty in nitrogen was not equally,

or even more, the limiting factor. Can the plant, by lowering its content of this constituent continue growth if moisture is available? That this can be done is indicated by the nitrogen of the corn fodder on plat 5 being only .84%, while this constituent in the corn fod- der of three other plats determined was nearly gouble this amount. Had the moisture and nitrates of the soil been equally limiting factors we would expect the content of this constituent to be about the same as in the other pitats.

In the other plats of the north series during the drought (see column Aug. 19 & 26) a great variation was noted even jn the checks (plats 1, 4, 7, 10, & 13), Plat 7 is notably low. Plat 1 has a moderate amount. This is the heaviest soil of this series. Diffusion be- ing hindered in consequence, what is the limiting amount for growth of corn or for checking the accumulation of nitrogen by the plant? Plat 2 (scraped) is high in Plat 16, which is a check in the second series

whup Fan FCOg come ’ is the highest in nitrate content of any unfertilized plat.

nitrates.

Plats 14, 15, and 17 fertilized with a heavy

application of sodium nitrate, failed, at least, to give

~ 123 -

any material increase in the crop. Evidently the

lack of nitrates in these plats can not account for the low yields. But the moisture ran low, which was doubtless one of the causes, of the cause, for the low yields.

It appears, therefore, that the lack of nitrates in the soil was probably a limiting factor, at least, in the amount of nitrogen accumulated by the plants in some

cases while in others ro such effect occurred from this cause,

A very interesting feature of the tablg (XXXIT) is the variation of NOg in the checks. Is it improbable that plat 7, for instance, is too low to supply the opti- mum amount of nitrates to the plant if the moisture and other conditions were favorable? what effect would this have on the composition of the plant? Sodium nitrate applied to timothy on the Mitchel Farm gave a decided increase in Yield (Cornell Bul. 241, 7)

The Pog content in the soil was about the same throughout the season, and is but slightly lower in the corn than at the ends. There was but little effect on the This corresponds with the fact that acid phos-

yields. phate gives but slightly increased yields on the Mitchel

Farm. Ay The Potassium (K) in the soil seems to show

a slight tendency to lower on the ends with the moisture,

- I24 -

while in the corn there is, percentagely, considerable de« crease. Where potassium sulphate was applied it seemed to be somewhat reflected in the yields. This corres-

ponds with the increase in yield when applied to timothy,

to which reference is made above.

-- YIELD OF NTTROGEN IN CROPS --

A chemical analysis was made of corn fodder from plats 2, 53, 5, and 10, of millet from plats 5 and 6, and of soy beans, weeds, and grass from plat 9, and soy beans from plat 11. Care was taken to select what appeared to be representative samples. Two hills of soe with three stalks each and small composite samples of millet and soy beans were taken. In each case the sample of millet and soy beans consisted of about equal parts taken from the ends and in the corn. It will be noted that the samples were rather small for the purpose. The calculated

results for the above plats, together with other plats

taken for comparison, are given in Table XXXXVI.

- 125 -

TABLE XXXXVI SHOWING NITROGEN REMOVED BY THE CROPS ON SOME PLATS. AND THE NITROGEN IN THE SOIL 2 - 7 INCHES SEPT. 16. YIELD AND NITROGEN CONTENT OF CROPS GIVEN IN DRY MATTER

Crop Yield Nitrogen

No. In Corn Ends Rate per acre % Plat Lbs.

2 Corn fodder 3643 1.49 3 a z 4952 1.39 4 ’ se 4357 #1.38 5 is e 1609 84 5 Millet 3932 Tw LB 5 i a a oe 2 Millet 4999 1.16 6 Corn fodder 4528 #1.58 6 Willet 180 3.04 4 Corn fodder 4776 #1.58 8 is s 4913 #1.38 8 Millet 291. #235 04 9 Corn fodder £145 sreeae 4 BO 9 #e2eSoy beans 2090 1.49 9 Soy beans 3700 1.49 10 Corn fodder 4190 1.37 ll a . 3310 #1.38 11 Soy beans 554 3045

xAverage per cent nitrogen content of plats 3 and 10 taken.

eeThe same per cent nitrogen employed as for millet in plat 6. eee, " '! ft " " Us " corn ” " 5 «

seaeSoy beans constituted about 50%, weeds and grass constitut- ing the remainder.

- 126 -

TABLE XXXXVI SHOWING NITROGEN REMOVED BY THE CROPS ON SOME PLATS AND THE NITROGEN IN THE SOIL 2 ~ 7 INCHES SEPT. 16. YIELD AND NITROGEN CONTENT OF CROPS GIVEN IN DRY MATTER. (Contimes )

. NOs Nitrogen removed Total Nitrogen Nitrogen in Plat by crop. Rate per acre removed by crop Soil 2 - 7" rate per acre Sept .16. Lbs. Lbs. Lbs.

2 54,28 54.28 41.6

3 68.84 68.84 10.8

4 60.13 60.13 4.2

5 13.52 c

5 45.61 59.13 1.8

5 58.00 58.00 6

4 62.49 62.49

6 5.47 67.96 264

7 65.91 65.91 10.0

8 67.80

8 5.80 73.60 5.0)

9 L756

9 31.14 48.30 Lat

9 55.13 55.18 B96 10 57.40 57.40 8.5

Al 45.67

- 127 -

The manner of securing the results are clearly open to objection, but they may show some indications. Plats 5 and 9, when compared with the whole,show a de- crease in nitrogen in the crop, but when compared with plats 4 and 10 respectively, the decrease is but slight except where corn grew in Plat 9. The corn in this plat is cal- culated the same as in Plat 5, which is probably too low since the corn yield was 33% greater in Plat 5. Allowing for this probable error, there appears to be about the same yield of nitrogen in the ends as in the cory on these two plats.

The nitrogen in 2 to 7 inches of soil is lower in these plats than any of the others. Plat 2, which was scraped, shows the highest amount of nitrogen in the soil of any of the plats, but the total nitrogen in the crop was low.

-- CAPILLARITY --

For the study of the differences in the capillary power of the soil the results from plats 1 to 13 were used, since the greatest variations in texture occurred in these plats. The variations from the approximate normal for the

different plats, and between the ends and in corn is shown

in Table XXXXVII.

- 128 -

TABLE XXXXVIT PER CENT AVERAGE MOISTURE, NORTH SERIES, (PLATS 1 T0 13) CALCULATED ON THE BASIS OF AVERAGE MOISTURE CONTENT ENDS OF PLATS JULY 9TH, & 16TH.

No. July 9 Aup. Sy 19, 28, & Sep. 16. Aug. 19 & 26. Plat & 16 Ends Ends In Corn Ends Ly Dorn

1 ee re 76.4 ms ae 2 22.55 81.0 66.6 71.50 bee? 3 26.3 95.2 68.0 92.1 52.5 & 21.4 85.2 64.1 79.3 48.2 5 20.8 47.3 46.5 £28.35 27.4 6 21eS 80.0 61.8 F1s@ « 45.6 7 20.05 88.0 70.8 81.4 56.0 8 20.45 85.0 Fils 81.4 88.9 9 16.65 60.2 56.2 42.9 3742 10 LT od. 88.9 71.6 83.7 61.8 11 16.35 79.6 70.4 76.2 59.6 12 14.9 87.5 94.7 84.0 90.0 13 16.3 90.4 84.0 88.0 81.4

For the basis of calculation the average moisture

contant of the ends for July 9 and 16 when the moisture

was presumably not far from the optimum was taken. This

was some too low for plats 5 and 9, but the error due

to thig cause is not material.

- 129 -

The most interesting features of this table are the results from plat 12, where there was only a very light growth of soy beans in the corn. Not only was the percen- tage of the optimum moisture higher than on any of the other plats, but was higher in the corn than in the ends, These averages can not be due to any aberrent determinations for an examination of the detailed data (Table "A" Appendix) shows that for each determination the same differences are shown. Some of these determinations were made before any soy beans were above ground. This is the more inter- esting on account of this being the highest plat of the whole experimental area. Had this been a heavier soil there would be a possibility of a water coming to the sur- face where the corn was growing from higher ground, but even under this circumstance the very slight difference between the elevation of this plat and the level of the land above would make such an explanation improbable. It appears, therefore, to bedue to strong capillary action. The protection against evaporation by the corn appears to

conserve more moisture than is transpired by the plants.

- 150 -

Table A: Showing Moisture and Nitrogen, (NO) &n Soil. Plats,1l=-15. Corn Planted May 17,1907. ENDS, July 9

ie Treatment, ary sotl,ary soil, sate: BE Cultivated all season, 24.5 7926 325 2 Scraped, 21.7 116.6 537 3 Mulched, 25.7 73.9 288 4 Cultivated all season, 22.1 98.0 443 5 Millet sown June 18, 20.6 84.8 412 6 Millet sown July 24, Blee 79.0 aT 7 Cultivated all season, 19.9 99.1 : 498 8- Millét sown Aug. 6, 20.7 100.0 483 9 Soy Beans sown June 18. 16.2 98.6 609 10 Cultivated all season, 17.4 54.4 313 1 Soy Beans sown July 24 16.5 ES, 0 321 lg Soy Beans sown Aug.6 14.9 54.8 367 13 Cultivated all season, 16.5 57.25 349

*ppm,is the abbreviation for parts per million.

- 131 - f

Table A{Cont. ): Showing Moisture and Nitrogen, (NO,) in Soil Plats, 1-15. Corn Planted May 17,1907.

Noe ENDS, July 16. ENDS. July 23. Plat, HoO0 % NOs ppm. NOs ppm. H0 % NOsppm. NOx Ppm. d.soil, d. soil, Hod. . d.soil,d.soil, #00. 1 23.4 84.5 361 21.3 78.0 366 2 25.4 91.0 389 21.6 97.0 449 3 26.9 39.0 145 26.7 84.0 315 4 20.7 88.4 427 19.8 110.0 555 5 21.0 72% 347 17.28 29.9 168 6 21.4 78.0 365 19.9 113.7 571 B 20.2 81.4 405 18.7 78.4. 419 8 20.2 61,7 305 19.1 101.4 531 9 17.1 60.5 353 15.0 75.6 504 10 16.8 33.6 200 16.2 84.0 519 11 16.2 26.4 163 15.5 73.8 a6 12 14.9 34.2 230 14.0 75.6 540 13 16.1 30.0 186 16,7 81.6 520

Pa

Table A(cont. ): Showing Moisture and Nitrogen, (NOz) in Soil.

Plats,1=13. Corn Planted May 17,1907.

ENDS, July 30. ENDS, Aug. 8 ' No. He0 % NOz ppm. NOsppm. Ho0 % NOx ppm. NOg ppm. Plat,desoil, desoil, Ho0. desoil, d.soil, 4H,0. 1 21.2 78.4 370 21.1 90.0 427 2 18.7 84.0 449 18.3 84.0 458 3 24.7 76.0 308 26.8 61.7 240 4 17.9 91.8 513 18.1 111.0 612 5 12.1 6.6 55 12.8 262 17 6 19.3 73.4 380 19,8 135.0 701 7 15.3 67.8 443 18.0 96.0 533 8 17.6 79.8 453 17.3 135.0 780 9 11.1 19.2 173 11.6 8.8 76 10 15.5 52.2 337 15.6 7301 468 11 14.5 54.0 373 13.6 56G6 416 12 13.9 45.1 325 12.8 66.0 515 13 15.2 60.0 395 14,4 56.1 390

- 133 -

é

Table A(cont%.): Showing Moisture and Nitrogen{NOz) in Soil.

Plats,1=-15. Corn Planted May 17,1907.

No. 30% PROS pom. NO; ‘ies H,0.% ae ee a. ppm Plat,dssoll, a. soil, H50. a: soil, dsoil, #50. 1 19.6 51.9 362 20.6 90.0 436

2 16.7 3J.2 223 17.1 7526 442

3 21.8 32.4 149 24.5 101.4 416

4 16.5 49.2 298 17.5 96.0 548

6 12.8 3.8 26 8.2 6.5 79

6 17.3 58.2 337 16.6 81.6 491

7 16.6 63.0 386 1741 84.0 490

8 17.9 67.2 375 17.2 111.0 646

SB: glee 6.6 57 8.4 4.0 47

10 «13.4 23.6 176 14.9 62.1 418

1% “4ay1 35.0 234 16.5 75.0 454

1 »3=-:14.7 28.6 194 12.6 72.1 577

13. «13.6 18.1 133 14.1 78.6 587

- 134 -

Table A(cont.): Showing Moisture and Nitrogen (NO) in Soil Plats,1le«135. Corn planted May 17,1907.

ENDS Aug. 19 IN CORN.

Plet,accont, aeonity Boon ao Pee

1 20.0 72.0 359 15.3 18.6 122.5

2 16.1 51.6 320 11.3 24.7 219

3 24.1 97.5 404 14.6 6.6 45 4 17.2 84.0 439 10.4 16.5 159

5 6. 2 doe 24 5. 5 2.0 36

6 16.0 60.0 375 11.0 11.5 105 7 16.5 54.0 328 11.9 8.8 ° 74

8 16.8 84.0 500 13.2 24.7 187 9 0 3.0 43 5.5 5.5 104 10 14.7 50.5 344 10.6 13.7 129 ball 12.1 55.0 456 9.2 22.0 239 Le 12.7 55.0 433 14. 2 66.7 469 13 14.7 78.6 535 12.9 29.7 230

- 135 -

Table A(cont. ): Showing Moisture and Nitrogen (NO.) in Soil Plats,1-12. Corn Planted May 17,1907.

TENDS... “fuge 26 IN CORN NG. Ho0% NOz ppm.NO.ppm. Ho0 % NOz ppm. NOzppm. Plat, d.soil,d.soil, H,0- d.soil, d,soil, H,6- a 19.6 69.6 355 14.5 14.8 102 180k Tea 54.0 336 12.4 80.5 670 3 24.4 9725 400 13.0 40.1 309 4 16.7 91.8 548 10.2 16.5 162 5 5.6 2.0 36 5.9 2.6 ’ 42 6 14.2 41.2 290 8.4 10.0 119 7 16.2 79.8 492 10.6 10.5 99 8 16.5 93.6 567 10.9 25.0 230 9 v2 2.0 27 7.1 4,5 62 10 14.5 69.5 477 10.5 31.0 2965 11 12.8 65.0 430 10.5 32.5 315 12 12.3 68.7 559 12.6 67.5 455

13 14.0 69.3 495 13.6 41.6 05

- 136 -

Table A(cont.): Showing Moisture and Nitrogen (NO) in Soil. Plats,1«13. CornPlanted May 17,1907.

ENDS Sept.2 ENDS. Sept. 16 rude, ae Ee” | eee,” ee i 18,9 69,6 369 23,& 130,0 547 9. 716.7, | 45.0 270 22.3 172.9 775 3 23.9 117.0 491 25.6 86.2 336 4 17.0 96.0 ° 565 20.8 208.0 1000 5 6.0 1,0 17 16.2 2.2 14 6 13.5 25.5 187 18.8 6.0 32 7 16.6 73.8 444 20.1 145.0 + 712 8 16.3 66.0 405 19.0 45.0 237 9 71 2.0 28 14.2 10.0 70 10 14.9 87.6 588 16.1 165.0 1024 11 11.8 5e,e 442 15.6 145.0 533 12 14.3 90.0 630 14.1 44.0 312 13 14.7 90.0 613 15.7 183.1 1168

~ 137 -

Table A(cont): Showing Moisture and Nitrogen (NO,) in Soil. Plats,1-13. Corn Planted May 17,1907.

IN CORN Sept.16 No. H50 % NOs ppm. NOgppm. Plat,d.soil,d.soil, Ho0.

1 22.6 126.7 560 2 19.5 150.0. 768

is

& 22.3 $8.0 175

4 17.7 15.0 85 5: 14.5 6.6 45 6 15.9 8.8 55 7 17.2 36.0 209 8 16.7 18.0 108 9 13.4 6.1 46 10 14.5 30.8 Le 11 12.5 17.5 140 12 15.0 68.7 457

13 14.8 56.0 372

- 138 -

Table A: Showing Moisture and Fertilizer in the Soil.

Plats 14=26. Corn Planted May 17,1907.

Ho. ENDS.July 9 Plat, Fertilizer Treatment HO % Fer.ppm.* NOpppm d.soil d.soil HGO

14 775# Nit.Soda Cult.all season, 27.2 238.8 878 16 776 " * Millet sown July 24 25.3 267.1 1056 16 None Cult. all season, 24.0 91.0 379 17 775# Nit.Soda Millet sown Aug 6 25.6 240.6 10258 18 ; P04

775# Acid Phos. Cultivated all season, 22.2 P 9.7 oe 49 None, ‘ « $3.7 7.8 mee 20 775# Acid Phos. Millet sown July 24 20.5 7ol 0 mee 21 775% " " " " Aug 6 22.6 1 ae 22 None Cult.all season, op re 6.5 -—

K

pe " " ¥ e 21.3 10.4 --- 23 388# Sul.Pot. = a , 22.9 9.1 --- a4 " i Millet sown July 24 22.6 10.2 --- 25 None, Cult.all season, 20.6 1352 -——— 26 388# Sul.Pot. Millet Sown Aug.6 20.0 19.5 ===

* Fer.ppm,abbreviates Fertilizer parts per million.

- 189 -

Table A(cont): Showing -ioigsture end Fertilizer in the Soil. Plats 14-26.Corn Planted “ay 17-13°7.

No. He0 a ver a HG 3PPm H,0 eee pin Plat,d.soll d.soil 30. d?soil d.soll .Hp0. 1424.8 89 :162.5 655 23.9 221.0 925 15 24.5 195.0 796 24.6 247.0 1004 16 25.2 130.0 560 23.7 162.5 686 17 «23.5 195.0827 22.1 287.5 1294 e221 1140 21.1 “7 19 3.. 21.5 947 21.8 8.5 29 © 21.0 13.0 19.7 8.8 21 21.6 8.4 21.4 7.8 22 «19.5 7.8 19.3 7.1

K K

22 «19.5 Tad 19.5 147 2321.4 5.2 20.7 12.0 24 20.6 G44 20.0 8.4 25 20.0 = -1449 18.9 7.8

26 20.0 9.7 eau 9.7

- 140 -

Table A(cont.): Showing Moisture and Fertilizer in the Soil.

Plats 14=26. Corn Planted May 17,1907.

ENDS July 30 | ENDS Aug 5. No. HpO % Fer.ppm NOsgppm. Ho0 % Fer.ppm. NO,ppm. Plat d.soil d.soil #,0. “@.soil d.soil H,0. 1422.5 9178.0 780 23.5 235.5 1000 16 23.1 263.5 1097 23.7 ° 227.5 960 16 21.8 177.4 814 “2.2 146.2 666 17 —s 21.0 169.0 805 21.3 295.7 1388 PO; PO; < 18 18.9 748 19.6 72 19.5 1865 7.2 19.5 6.0 20 18.8 6.0 19.2 6.6 21 18.2 8.4 19.3 8.4 22 «1843s 18.0 7.2 K K 22 89« «18.3 4.5 18.0 7.8 23 19.1 9.0 19.2 10.8 24 19.2 7.8 18.6 12.0 25 17.6 8.4 17.3 10.2

26 17.5 12.6 16.7 10.2

- 141 -

Table A(cont.): Showing Moisture end Fertilizer in the Soil. Plats 14-26. Com Planted May 17,1907.

In Corn Aug.5 ENDS Aug.12

No. Ho0 % Fer.ppm. NOgppm. Ho0 % Fereppm. NOz ppm. Plat d.soil d.soil HO. desoil d.soil Hod. 14 21.8 210.1 965 22.6 208.0 920 15 20.3 240.0 1182 20..8 159.0 764 16 20.1 120.0 596 21.35 151.8 710 17 18.1 282.0 1560 21.0 180.0 R58

P04 PO4 18 18.2 gus: 19.3 6.0 1918.4 702 18.9 7.2 20 17.4 9.0 16.4 7.8 ee 15.8 Tek ise Tee

K K’ 22 15.8 9.6 Alege 4.8 23 16.9 12.0 19.4 6.6 24 16.4 13.2 -: 15.6 7<2 25 14.7 8.2 16.9 5.4 26 14.6 13.4 17.0 9.6

- 142 -

Table A(cont.): Showing Moisture and Fertlizer in the Soil

Plats 14-26 Corn Planted May 4@7,1907

ENDS Aug.19 InCorn Aug.19 an tents | | ea ae toe 14 «21.5 156.0728 16.3. 150.0 920 15 18.8 126.0 675 14.0 132.0 ot 16 21.3 120.0 564 14.1 66.7 472 17 19.8 165.0 834 12.2 129.2 1060 3 (ante seh 1s? Pate 19 18.8 9.6 12,6 a1 *

20 14.8 77 11.5 7.7 ry eC ep 7.2 11.5 7.7 22 «216.6 — 11.8 6.0 a = 22 «616.6 4.2 11.8 3.8 23 18.6 9.6 11.4 6.0 24 14.0 6.0 9.3 4,5 25 16.2 6.0 10.3 4.4

26 15.6 11.0 9.5 6.5

~ 143 -

Table A(cont.): Showing Moisture and Fertilizer in the Soil. Plats 14-26 Corn Planted May 17,1907.

Ends Aug 26 InCorn Aug 26 Noe H,O % Fer.ppm NO_ ppm. He0 % Fer.ppm. NO ppm. Plate &.soil d.soil #50. d.soil d.soil H50. 14 21.1 159.6 756 15.3 137.8 ROB 161 17.3 175.8 1014 12,7 165.0 1300 16 21.1 Loc 60 640 13.7 97.5 BFE L? 19.5 182.6 942 12.0 207.6 1692 PO, PO4 18 18.6 10.2 11.8 9.0 19 18.1 9.0 13.9 9,9 . 20 14.0 &.8 11.6 ALE ok 17.6 9.0 16.9 7.5 22 16.5 9.6 11.4 0 K K 22 16.5 6.0 11.4 4.0 23 18,1 9.6 11.35 ee) 24 lied 6.1 &.7 6.8 25 16.4 6.6 10.7 E.0

26 16.6 10.8 9.4 1E.3

- 144 -

Table A(cont.): Showing Moisture and Fertilizer in the Soil

Plats 14-26 Corn Planted May 17,1907.

ENDS Sept.2 ENDS Sept.16 No. Ho0 % Fer.ppm. NOgppm. bod © Fer.eppm. NC,.ppm. Plat desoil d.soil HoO, desoil d.soil Hoo. i4 Shea 16220 &70 284 387 EF £580 15 16.5 126.0 76F: 25.5 720.0 1520 16 20.9 143,0 684 OCs8 240,£5 940 17 20.8 151.4 750 25.6 278.0 1470 PO, PO 18 18.8 9.0 24.7 10.4 19 18.4 9.6 23.6 9.1 20 12.8 7.0 Slee 10.4 21 16.2 10.2 Bee 11.0 22 16.9 ee 20.4 9.7 K K 22 10.9 8.4 20.44 Be 23 Lite? 10.2 ure 8 11.7 24 & 8 6.5 20.5 6.2 26 = s-«16.4 9.0 20.1 24,0

26 1E <3 11.4 19.6 7.2

- 145 -

@atle A(cont.)}: Showing Woisture and Fertilizer in the Soil. Flats 14-26 Corn Planted iiay 17,1907 In Corn Sept.16 No. H.0 % Fer.ppm. NOsppm. Plat desoil d.soil hoede 14 22.6 325.0 1440 15 20.5 130.0 634 16 22.2 162265 738

bg 19.2 210.0 1090

PO, 18 19.9 ee4 19 20.8 9.7 ° 20 18.0 7.8 21 18.9 10.8 22 19.3 9.6 K 2 19.3 E64: 23 19.0 Tel 24 17.4 4.8 25 1750 5.4

26 15.8 7.7

- 146 -

¥

-~ FURTHER STUDIES OF THE SOIL --

Some further studies were made of the soil in dif- ferent plats. Pore space, specific gravity, and rate of evaporation were determined. It was thought possible that a correllation might be shown between variations in some of these properties and the variations in yield, and that some changes might have occurred as a result of variations in treatment. There were also opportunities for some other observations.

-- PORE SPACE AND SPECIFIC GRAVITY a

Scil to the depth of 7 inches was taken in cylinders 7 inches deep by 6 inches in diameter. The capacity of the cylinders was carefully measured with water. Two ser- ies were obtained, the first November 20th. just after a thaw and the second November 2ist.

Unless otherwise stated the first series was taken at the north end of each plat just beyond where the corn grew, and the second near the middle of the plat. 22a refers to the north end of Plat 22, which was clearly the poorest spot of the field, and 22 refers to the middle of the plat where the soil was gradually changing to the de- cidedly better part of the plat on the south end. No freeze or precipitation occurred bétween the taking of the samples. Both series were weighed and the moisture was determined from

the samples taken on the side of holes from which the cylinders

of soil were taken.

- 147 -

The series taken November 21st. was also immersed in water for three hours, letting the water rise from beneath, removed and immediately weighed in a scale pan. The pore space for the series taken November 20th.(Table "B" Column 8) and November 2lst. (Table "C" Column 8) was calculated according to the following formula.

Capacity _ Wt. dry soil(gm) (1) Cylinder (c.c.) Sp. Gr. Per Cent

Pore Space Capacity Cylinder (c.c.)

The pore space for the series taken November 2lst. (Table "C" Column V) was also calculated by the following

formula:

Moisture in soil Water of Sat- (2) when taken(gm) + uration (gm) Per cent Pore Space

Capacity of Cylinder (c.c.)

The specific gravity was determined with a pyk- nometer from the samples used for moisture setermination in both series. The results from each series correspond

closely so the average of the two is used in the tables

which follow:

- 148 -

TABLE "B" SHOWING MOISTURE, PORE SPACE AND SPECIFIC GRAVITY, SAMPLE TAKEN NOV. 20TH.

‘* it ae IV Vv VI VII VIII No. Capac- ipo ta< Wt.Dry Sp. Volume Pore Space Plat ity ture soil gr. Soil aoe vA Cylin- in der soil Cas WA gms. Bote BBs t

1 3220 23.50 4457 2.64 1688 1532 47.5

4 3255 20.56 4319 2.63 1642 1618 49.6

7 3220 17.16 4398 2.64 1666 1554 48.3 10 3225 13.76 4187 2.67 1568 1657 51.4 16 3240 26.85 4137 2.62 1579 1661 * 6148 19 $240 25.02 4131 2.63 1571 1669 51.5 22 3220 23.02 4425 2.65 1670 1560 48.3 25 3235 22.46 4343 2.62 1658 1577 48.7

2 3225 21.39 4399 2.63 1673 15.82 48.1

3 3240 24.25 4564 2.63 1735 1505 46.5

3 3230 24418 4240 2.65 1612 1618 50.1

5 3195 20.34 4516 2.63 1717 1478 46.2

9 3245 13.97 4678 2.64 1772 1473 45.4 23 3245 23.91 4017 2.62 1682 1712 52.8

* The moisture here as in all other cases is calculated on

the basis of dry soil unless otherwise stated.

- 149 -

“TABLE "C" SHOWING MOISTURE, PORE SPACE AND SPECIFIC GRAVITY, SAMPLES TAKEN NOVEMBER 21ST.

I TT tI

No. Capac- Mois- Plat ity ture CGylin= in

der soil

1 3220 27 46

4 3255 25.89

? 3220 te

#Calculated according to formula 1, page 147

eeCalculated according to formu

IV V Wt. Dry Sp. Soil Gr. Ss.

4061 2.64 4058 2.63 4000 2.64 4489 2.67 3962 2.62 3945 2663 4240 2.65 4153 2.62 4110 2.63 4296 2.63 4056 265 4389 2.64 4225 2-65 4005 2.62

vr Volume SO2.4.

VII

C.C.

VIII Pore #1

%

C40.

de

52.55 52.60 52.95 47.68 55.55 53.70 50.46 51.25 51.53 49.60 51.73 48.78 50.65 52.88

la 2, page 147.

1595 1660 1668 1520 1702

‘1659 1529 1569 1644 1598 1612 1577 L587 1681

49,53 51.00 51.80 47.13 52.53 51.23 47.34 48.50 50.98 49.47 50.45 48.60 47.28

57.80

- 150 -

TABLE "D" COMPARISON OF PORE SPACE November 20 November 21 No. Location Pore Location Pore Space Plat of sample Space of Sample By formula By formula of, #1 #2 s LT TET. IV V VI a No.end 47.5 Middle of 52,83 49.53 of plat plat 4 " 49.6 " 52.60 51.00 7 " 48.3 e 52.95 51.80 10 . 51.4 ¥ 47.88 47.13 16 u 51.3 . ere) 52.53 19 " 61.5 " 53.70 51.23 82 ' 48.3 " 50.46 47.34 26 Ms 48.7 ‘i 51.25 48.50 2 . 48.1 * 51,55 50.98 3 ” 46.5 " 49.60 49.17 5 " 46.8 8 51.73 50.45 9 " 45.4 " 48.78 48.60 23 Middle of 52.8 am 5288 51.80 plat 3° Near mid- 50.1 dle of plat 22a . North end 50.65 47.28

of plat

5l -

The tables show inconsistencies indicating that the sampibs should be composite. Some of the differences might have been eliminated by determining the moisture content from the soil in the cylinders rather than from that from the side of the holes from which the samples were taken.

The Specific Gravity (Tables "B" and "C" shows an irregular tendency to slightly increase from plats 1 to 13. Plats 10 and 22, which represented almost the extremes in production capacity and presumably of tex- ture, had a slightly higher specific gravity than any of the other plats. There seems to be no correlation either direct or the reverse between the specific gravity and the productive capacity.

The pore space column X Table "C" is uniformly smaller than that in column VIII. While column X was calculated by the more direct method (formula 2, page 7147) it seems that some of the water was lost by transferring the sample to the scale pan.

Comparing the samples taken November 20th. and 2lst. (Table "D", III and V) both calculated by the in- direct but more dependable method, it will be noted that those taken November 20th. at the end of the plats imme- diately after a thaw had less pore space than those taken

the next day from the middles of the plats. Since noe

- 152 -

crops grew on the ends of the check plats, it would seem that the phenomenaymight possibly be due to the influence of the crop. But plats 5 and 9 show the same differences, and the ends of these plats produced practically the same crop as their middles.

The moisture content November 2lst.(Table "C",III) was contrary to appearances higher than on November 20th. (Table "B", III). No precipitation or freeze occurred petween the taking of the samples, On November 20th. the surface was sticky. The soil cylinders were sunk one fourth to one half inch beneach the surface, thus eliminat- ing this portion, but the soil beneach this was also notably more sticky than the day following, when it worked fairly well. It would seem that the freeze localized the moisture, and after the thaw it was redietributed. There wohld seem to be a correllation between this and the increase in pore space noted above.

On the whole, the plats which were not cultivated (Plats 2, 3, 5, and 7) show less pore space than the others. Had the samples been taken earlier in the season, perhaps the difference would have been more marked. Plat #2 has a higher per cent pore space than any of the other unculti- vated plats. The mulch had been removed from Plat #3 pre- vious to taking the samples. Further correllations do

not seem to exist.

~- SUGGESTIONS FOR DETERMINING PORE SPACE ~--

In the light of the experience gained in securing

the pore space here tabulated a few sucgoations are made. It aphbears that setting total weight and deterrmining rois- ture and specific gravity, and from this data calculating the pore space, is more dependable than the direct method by adding water. Only ore cylinder is needed thus ob- vlating errors due to lack of exact measurements. “ince the variabilitv is small it is essential that errors be eliminated as far as possible. Composite cvlinders of soil should be weighed in tre field and the sample for moisture and specific gravity determination taken from the whole of the samples aftr thoroughly mixing. Tf striking variation occurs probably this should be eliminated, as any compacting factor, such as the step of a horse, for instance, would cause a sample not to be comparable; If this eliminationis not resorted to a larger number of sam- ples should be taken from the plats when much variation occurs.

-- RATE OF EVAYPORATION AND LOSS FRO}! DRAINAGE --

Rate of evahoration from platinum dishes

Soil from samples taken for moisture determi-

nation Nov. 20th. (Table "B") was used. Platinum dishes were filled, packed by jarring uniformly, and struck. The samples were placed in a room 1 few feet from the

radiator. The results follow in taple "Es

TABLE

No. Plat

"mE" LOSS OF WATER BY EVAPORATION

Wt. Dry Soil

gms.

TF

211.99 215.29 LO Be 208.20 200.16 172.32

P01. 1S

" 191.96

204.61 196.23 187.42 186.18 198.48 200,64

Moisture

gms.

BEL

49.82 43.86 33.11 28.58 53.73 43.11 46.30 43.12 44.76 47.59 44.91 45.01 40.358 28 04

of fe

IV

25-50 20.56 Lf <le 15.73 26.85 25.02 25.02 22446 Sled 24.25 25.91 24.18 20.54

13.97

~ 154 -

Rate loss per 3 days 3 = 7

ems.

days

ems.

FROM PLATINUM DISHES

Gay For ee 7 - 10 10 - 13 13-17 H.o days days days at, end. 17 da. ems. gms gms gms. Vil VIII IX xX 2.23 89 -06 2.85. 1.78 42 -.01 2.01’ Land ell -.O1 1.47 66 05 =,01 1.43 2008 -86 202 Bie 1.81 24 00 1.89 1.89 255 -.01 1.93 LoD? 3.6 ~.02 1.90 1.97 . 5& OF evil Pa dee -69 00 2.16 1.90 40 -00 1.91 2.07 ol? 00 2.07 1.84 .24 -.01 1.65 ~193 4S ayn. Ayes

- 155 -

The rate of evaporation diminished fairly uniform- ly till the hygroscopic moisture was reached. The “drought limit" for corn appears to have been reached before the first weighing was made at the end offthree days. The data would have been more valuable had the weighings been made at closer intervals,

RATE OF DRAINAGE AND EVAPORATION FROM CYLINDERS OF ~- SOIL --

The cylinders of soil taken November 21st. (Table "C") for the determination of pore space were used. Im- mediately beneath the soil was cheese cloth, the whole being supported by galvanized wire netting one sixth inch mesh. The cylinders with accessories were supported on sticks in pans, allowing a free access of air beneath. Covers of glazed paper and boards were used, thus prac- tically eliminating the loss of moisture to the bottom of the cylinders.

They were placed in the room used for evaporation from platinum dishes under what appeared to be uniform

conditions. The results follow in Tables F, G, & H:

~ 156 -

TABLE F ORIGINAL DATA ON DRAINAGE AND EVAPORATION FROM CYLINDERS OF SOIL

No. No. Plat Cylin-

der

L Le

L af

“ 4

i vi

10 10

16 16

19 19

HOR oy

25 25

2 2

3 3

5 5

9 9

22a ae

23 23

poorest soil o

the middle of each plat

&

22a, was taken from the no

Capac- ity

Wt. Cylin-

der

Cylinder

rack Stead

Ty

Total Weight

wie, SOL1 at

o~-~ taken from

tn pi eld

f the field ocurred,

%

6

gus fee gms.

Moist- ure in field

Total Wt. saturated cylinder

Gms.

VII

6127 6186 61 39 6475 6112 6071 6237 6180 G22] 6361 6140 6442 6220

6155

rth ena of the plat where the

while £2 was taken from near

as was done with all the other samples.

- 157 =

TABLE "F"CONTINUED ORIGINAL DATA ON DRAINAGE AND EVAPORATION

FROM CYLINDERS OF SOIL.

Weight after No, 1 Hour 2 Hours 24 Hrs. 3 Days 6 3/4 9 3/4

Plat days days Gms. Gms. Gms. Gms. Gms. Gms.

I VIII IX X XI RIT XIII

1 5905 5895 5828 5722 5615 5047

4 5898 5892 5823 5716 5539 5466

7 5856 5840 5782 5691 5510 5399

10 6296 6284 6209 6101 5907 5791, 16 5890 5870 5800 5684 5615 5440 19 5862 5851 5784 5675 5508 5450 22 6007. 5992 5933 5820 5697 5625 25 5995 5984 5903 5790 5604 5527 2 5974 5964 5884 5775 5654 5586

3 6137 6127 6050 5940 5820 5755

5 5906 5895 5e17 5704 5549 5481

9 6254 6247 6172 6065 5868 57358

22a °° 6013 600% 5931 5804 5648 5577

25 5885 5864 5803 5704 5624 5425

- 158 -

TABLE "F" CONTINUED ORIGINAL DATA FOR DRAINAGE AND EVAPORATION

FROM CYLINDERS OF SOIL Weight After

No. Plat 22 Da. 27 Days 3% Days 41 Days 48 Days 57 Da. 67 Da.

Gms. Gms. Gms. Gme. Gms. Gms. Gms, I XVI XVII XVIII XYX XX XXI XXII i 5313 5214 5092 4987 4930 4847 4785 4 5219 5129 5087 4942 4888 4811 4757 9 5131 5050 4944 4867 4822 4745 4696 10 5507 5421 5318 5253 6210 8142-5098 16 5173 5066 4937 4855 4796 4714 4655 19 5145 5044 4923 4834 4773 4691 4633 22 5362 5264 5140 5045 4990 4913 4864 25 5274 5182 5069 4994 4945 4866 4812 2 5347 5254 5136 5045 4987 4905 4849 3 5538 5455 = 8328 5230 5f67 5077 5015 5 5233 5148 56042 4963 4910 4831 4773 9 5433 5335 5232 5165 5117 5052 5005 223 = 5294 5198 5080 4994 4928 4918

25 BLOT 5095 4987 4894 4836 4758 1702

- 159 - TABLE "G" SHOWING RATE OF LOSS OF MOISTURE FROM CYLINDERS OF SOIL

Rate loss moisture per day in grams

SUE +

H j ort i }

No. 4 end. 2- 24 Ist. 1-3 3-6 3/46 3/4- 95/4 13 te Plat Ist.Hr. Hr. Hrs. Day ' Day ‘Days 9 3/4 dato13 17 I III IV VO VE)ovar. viet ix ¥ i

1 222 10 67 299 || 53 28.5 22.6 18.5 19

4 288 6 69 368 : 53.5 47.2 24.5 19.4 19.5 7 283 16 58 357 45.5 48.8 37 22.7 22.0 10 179 a 75 266 1 54 Bly? 38.6 26.8 23 16 222 20 70 312 58s 45.1 25 ° 24 22.9 19 209 ig 67 £87 54.5 44.5 26 24 23.2 22 230 15 59 304 | 56.5 32.8 24 22.1 20 25 185 iia 81 277 ; 56.5 49.6 25.6 23.7 19.5 2 247 10 80 337 | 55.5 51.7 22.6 19.1 19.7 3 2244 10 77 311 55 = BR 21.6 17.9 1¢ 7 5 234 1 78 323 | 56.5 41.3 22.86 21.5 18.2 9 188 7 75 270 ! 53.5 62.5 43.3 30.2 27.2 22a 207 10 Fe 289 | 63.5 41.6 23.6 24.9 23.7 23 270 21 61 352» «49.5 48 33 22.5 28.0

- 160 -

TABLE G CONTINUED SHOWING RATE OF LOSS OF MOISTURE FROM CYLINDERS

OF SOIL Rate loss moisture, per day in grams Moisture retained No. 17 -22 22 - 27 27 - 34 days 34-41 41-48 48 -57 57-67 Gms % Plat Days Days Days Days Days Days I a XII XIII XIV. XV XVI «XVII XVIII XIX 1 19:46 19.8 17.4 15 &.1 9.42 6.2 252 6.25 4 21.2 18... 14.6 Leak “Feat 8.6 5.4 231 5.69 7 20.6 16.2 15.1 dd, 6.4 8.6 4.9 225 5.62 ig 21 17 <2 14.7 9.8 Bal 7.6 ° 4.7 140 3.12 16 20.4 21.4 18.4 11.7 8.4 9.1 5.9 245 6.18 19 22.8 20.8 17.3 ae eee 9.1 5.8 221 5.60 SB 21.6 19.6 oh g's 13.6 7.9 8.6 4.9 157 3.70 eS 19,8 18.4 16.1 10.” 7.0 8.8 5.4 202 4.89 2 16.6 18.6 16.8 13.3 8.0 9.1 5.6 272 6,62 3 17.6 16.6 Anak 14 9.0 10 “6.2 248 5.77 B “pL 17 15:61 Liles 726 8.8 5.8 246 6.07 9 22.8 19.6 1477 9.6 6.9 7.2 4.7 141 3.21 22a 21.4 19.2 16.8 12.3 G44 125 2.96

28 18.6 18.4 15.4 13.3 8.3 8.7 5.6 229 5.72

TABLE "H" No. Wt.dry Water in Water in Plat Soil Saturated soil as soil taken from field Gms. Gms, fe dry soil 4% I II rit IV Vv 1 4061 1596 39.30 27 646 4 4058 1660 4091 25.89 7 4000 1668 41.70 22.11 10 4489 1520 33.86 15.20 16 3962 1702 42.96 28.07 19 3945 1659 42.05 27.88 22 4240 1530 3608 23.75 25 4133 1570 37.99 23.04 2 4110 1644 40.00 26.87 3 4296 1594 37.14 25.29 5 4056 1613 39.77 24.96 9 4389 1578 35.95 16.36 92 4225 1527 36.14 25.18 23 4005 1682 42.00 24.15

- 161

MISCELLANEOUS DATA ON TEST WITH CYLINDERS OF SOIL

Water lést in 54 days

Gms.

Water in soil at end of 34 days

VII VIII IX

561 35.15 13.81 501 50.18 12.35 473 28.36 11.82 363 25.88 8.09 527 30.96 1330 ; 511 30.80 12.95 433 28.50 10.21 459 29 «24 Ediaisleds 559 34.00 13.60 561 35.19 13.06 575 51.93 12.70 368 25.32 8.39 387 25.34 9.16 514 50.56 1%.83

- 162 -

The loss from these cylinders was aided by gravity which assistance was continued throughout the experiment, th though in a diminishing degree as the experiment progressed. When the first few weighings were made it was noted that the cheese cloth extending beyond the under edge of the cylinders was moist under the samples from plats 2,3,7 &

10, and that this condition continued largest in the case of the latter. This assistance to evaporation rendeted

by the cloth would serve to increase the variation between the finer and courser soils.

After the loss from sensible percolation had ceased, the further loss rapidly declined till what seemed to be a fairly uniform level was usually reached. This fairly uniform level gradually became less pronounced as the soil became coarser till in plat 10 it was somewhat indefinite.

Table "G" shows the loss of water for the first hour to be very variable, plats 10, 25,and 9 being the lowest. By referring to Table "C", Column VI, it will be noted that where the pore space was determined by tak- ing the sum of of the water retained from saturation and the water in the samples as taken from the field (Formula 1), these plate give the lowest determination (of pore space) of any other plats except the two samples from plat 22,

Too much importance should not be attached to the variation in these latter samples since the various data show that

they often vary from what would be expected.

The correllation between the relatively small

- 163 -

loss the first hour and the low per cent pore space in- dicates that too much water was lost before the saturated samples were placed on the scale pan. This supports

the conclusion stated above that this direct method of

determining pore space is not dependable.

TABLE "I" } COMPARING MOISTURE CONTENT IN CYLINDERS WHEN THE FAIRLY UNFFORM LEVEL WAS REACHED WITH MOISTURE IN THE ENDS OF PLATS IN THE FIELD JDEY 9TH, 1907.

No. Plat Moisture when Moisture Calculated level reached of end plats from checks gt £ an 1 25.0 24.5 4 Bose 2201 7 G12 19.9 10 16,47 17.4 16 24.0 24.0 19 23.8 21.7 22 19.9 21.3 25 20.35 20.6 2 24.5 24.4 24.4 3 25,0 23.8 5 23.5 2246 9 LP ot 18.2 224 Pe.6

23 23.8 22.9

= 164 =

The amount of moisture which is shown in the table was determined at the end of 6 3/4 days for plat 22a, 9 3/4 daye for plats 1, 4, 2, 3, 5, and 23, and at the end of 13 days for plats 7, 10, 16, 19, 22, 25, and 9. By inspection of the table it will appear that the selec- tion of the points for which the catculations were made was slightly arbitrary. It would seem probable that the

level was reached in some cases between the dates at which

Areleerren the data was taken. But the closeness of agreement the

per cent’ moisture as calculated from this data with the moisture in the field July 9th. when the moistuPe was supposedly about the optimum indicates,that this is a fairly dependable method at tat in this soil, not- withstanding its variations, for the determination of the optimum moisture content. After the loss continued on the "fairly uniform level" for some time the rate of loss began to decrease slowly at first, then rapidly. The

moisture in the soil just before the most marked fall

occurred is calculated and show in Table "J".

- 165 -

TABLE "J"! AMOUNT OF MOISTURE IN THE SOIL WHEN THE FIRST RAPID FALL OCCURRED AFTER PASSING THE FAIRLY UNIFORM LEVEL, AND THE MOISTURE CONTENT IN THE CORRESPONDING FIELD SOIL GROWING CORN

Me si es

No. Plat Moisture When fall occurred im Boal in calculated growing corn from checks Aug. 26 4 z a 1 elegey = 14.5 4 10.2 10.2 i 9.9 10.6 ’ 10 8.9 10.5 16 13.30 Los7 19 13.0 13.9 ne 8.0 11.4 25 oie Rea 10.7 2 11.3 1361 3 10.8 11.6 5 10.7 10.1 9 8.4 9.2 22a 9.2 23 10.5

The moisture is calculated at the end of 41 days (Table G, XIV) for plats 1, 4, 7, 22, 2, 5, 5, & 23;

at the end of 34 days (XIII) for plats 10, 16, 19, 25, 9,

- 166 -

and 22a. These points as in the case of those for op- timum moisture content were all selected before the cal- culations were made. On the whole the results are usually below those found in the corn at a time when most of the plats were suffering for lack of moisture. Plat 10, however, was perhaps not suffering as much as the others, if indeed it was suffering at all, since capillarity appears to have been stronger in the soils of the coarser plats. The differences between the two columns are greatest in plats 1 and 22. The method appears to be fairky dependable for the determination of the relative drought limit

in these soils, but the results were not as conclusive as those for the optimum moisture. However, the greater variation in the resuhts for the "dought limit" may have been due as much to variations from the drought limit in the corn as in the results from the cylinders of soil.

The differences in the rate of aapillarity together with other factors would make it impossible to secure results in the field which were more than approxi- mations.

While these two results are below the drought lim- it for corn they are above that for some other plants. It should be remembered that this drought limit is considerably below the point where plants can make a vigorous growth,

Perhaps if capillary water is excluded, the water available

- 167 -

for the vigorous growth of corn would be that from slightly above optimum to the end of the "fairly uniform level".

The results gotten at the end of 34 days for all the plats (Table "H" IX) show a surprising consist- ency, with the exception of plat 22, which is somewhat low. From this it would appear that by calculating the moisture retained at the same time for all the plats about, or just previous to the most abrupt fall in most of the plats the results will not only give the relative so called drought limit for corn, but will be approximately the amount which will be available for corn. Plat 22, however, is the exception; yet this is not marked. Whether these results can be obtained with different soil types, or whether a variation in the conditions of the evaporation test would affect results can only be determined by fur- ther experiment.

The results gotten at the e nd of 67 days (Table H, XI) show differences in the same direction as at the end of 34 days, but the differences are per- centagely greater. The samples from plat 22 (22 & 22a) ran about the same as that from plat 10, It will be re- membered that the samples from plat 22 were takan from the poorest part of the whole series under experiment. Sam- ple 22a was taken from the north end of the plat Which was representative of the poor spot and 22 from the centre of

the plat ( as in the case with the other samples experi-

mented with) which was in the edge of this spot.

- 168 -

The yields show this plat not to be the lowest in production, but this is due to the south end being con- siderably better than the north end.

In conducting tests by this method, where data is secured at short intervals, uniform conditions should be maintained, especially as regards temperature. This is especially important as the drought limit is approached for the w#ability of the water film is increased as the temperature rises thas assisting drainage. The increase in Column XVI over XV (Table "G") is pebably dug to this cause.

But where it is desired to get only approximate results, as may be desired when selecting land for plat experiments, it would seem unnecessary to take such painstaking care. The optimum moisture could be gotten from the soil taken from the field at the proper time, and taking samples in cylinders for drainage and evap- oration according to the method above described. Make weighings of two or more samples till the last fallbe- gins to occur, then weigh all the cylinders and calculate results. It would perhaps be unnecessary to saturate the soil in the cylinders.

The determination of the moisture capacity of the soil detached from the field would seem to be of

value as a reconnoisance method for the selection of land

- 169 -

for field plats. This would perhaps usually give a fair indication of the uniformity of the land. But in the opinion of the writer a record of the growth of the same crop by plats for the yar preseeding the commencement of the experiment would be far more dependable. It should be remembered that the moisture capacity is only one

of the factors which affect the amount of water which the plants receive. Capillarity is a most important factor and varies markedly in different soils. On the other hand the productive capacity determined by growang a previous crop is subject to error from experimental var- iation, difference in seasons and change in productive capacity, even relatively, from season to season. Under some conditions this latter variation may be very marked. Where it is not possible to secure the yiplds a previous season, the determination of the moisture capacity would

aqme seem to be of, value.

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