Advances in agronomy volume 10

HARLAN, Geneticist,AgriculturalResearchService, United States Department of Agriculture, and Professor of Agronomy, Oklahoma E.. JORDAN, Soil Scientist, Eastern Soil and Water Management

u< OU_1 58850

CO

Call No. i 5*/ H*** * AccessionNX 3 t) fl

AGRONOMY

ADVANCES IN

AGRONOMY

Prepared under the Auspices of tlie

AMERICAN SOCIETY OF AGRONOMY

VOLUME x

Edited by A (i. NORMAN

University ofMicJiigan, Ann Arbor, Michigan

ALLHIGHIS RESERVED

WITHOUTWRITTENPERMISSIONFROMTHEPUBLISHERS

ACADEMIC PRESS I\C

NEW YORK 3, N ^

library ofCrm^rmCatalogCardNumber- 50-5598

I'RINlfcl) INTHE UNITEDSTATESOFAMERICA

W.S.GHEPIL,SoilScientist,WesternSoiland Water ManagementBranch,

UnitedStatesDepartmentofAgriculture,KansasStateCollege,

GEORGE H.DUNCAN, Professor Emeritus, Departmentof Agronomy,

LEONARD E ENSMINGER, Soil Chemist, Department of Agronomy andSoils,AlabamaAgriculturalExperimentStation,Auburn, Alabama

A L HAFENRICIITER, Plant Materials Technician (West), Soil

Oregon

II.R HAISE,Acting Head,Irrigation Practicesand RequirementsSection,Western Soiland Water ManagementResearch Branch, AgriculturalResearch Service, United States Department of Agriculture, Fort

JACKR. HARLAN, Geneticist,AgriculturalResearchService, United States

Department of Agriculture, and Professor of Agronomy, Oklahoma

E G HEYNE, Professor of Agronomy, Kansas State College, Manhattan,

Kansas

J. G HIDE, Professor of Soils, Department of Agronomy and Soils,

HOWARD V JORDAN, Soil Scientist, Eastern Soil and Water ManagementResearch Branch, Agricultural Research Service, United States De-partment of Agriculture, State College, Mississippi

E

J. KAMPRATH, Director, Soil Testing Division, North Carolina Stale

College, Raleigh, North Carolina

P.F.KNOWLES,Associate ProfessorofAgronomy, Universityof California,

Davis, California

A L.LANG,Professorof SoilFertility, DepartmentofAgronomy, sityofIllinois, Urbana,Illinois.

Univer-M Univer-M MORTLAND, Associate Professor in Soil Science, Michigan State

WERNER L NELSON, Midwest Manager, American Potash Institute

In-corporated,West Lafayette, Indiana.

R V OLSON, Head, Department of Agronomy, Kansas State College,

E C STAKMAN, Collaborator, Plant Pest Control Division, Agricultural

ResearchService, UnitedStatesDepartmentofAgriculture,and

Spe-cial ConsultantforAgriculture for the Rockefeller Foundation partment of Plant Pathology and Botany, University of Minnesota,

GEORGE STANFORD, Chief, SoilsandFertilizer Research Branch, Division

of Agricultural Relations, TennesseeValley Authority, Wikon Dam,

Alabama

C G STEPHENS, Head, Soil Survey and Pedology Section, Division ofSoils, Commonwealth Scientific and Industrial Research Organiza-

tion,Adelaide,SouthAustralia

S. B WEED, Assistant Professor of Soils, North Carolina State College,

Raleigh, North Carolina

LEROY H ZIMMERMAN, Research Agronomist, Agricultural Research

Agriculture, and Universityof CaliforniaExperiment Station, Davis,

California

This isthe tenthvolume of theseries It is withfeelings of both

passage of years, and gratification that this venture has found wide

ac-ceptance.TheEditorismuchindebtedtothemanyableinvestigatorswho

have been willing readily to prepare authoritativereviews of theirfields

ofinterest. Suchreviews doindeed advancethewholeprofession. Ninety

overlapping From time to time it is anticipated that there will be

thereader an accountandevaluationofrecent activities.Toadegreethechapter by Nelson and Stanford is of this nature and supplements theinformation on fertilizers and fertilizer practices presented by Jones andRogers in Volume I.

Perhaps it is also appropriate to repeat that in selecting topics for

review, and in discussing with authors the scope of their contributions,

edi-tors' definition of what constitutes agronomy is catholic; they will beguidedin theirchoicemore by whatinformationmay beofusetoagrono-

spread of race 15B of wheat stem rust.

dealing with regional agriculture. There are few areas that present agreaterdiversity ofagronomic problems than theGreatPlains.Olson and

his colleagues have discussed these comprehensively

Anotherfeature ofthis serieshasbeentheinclusionfrom timetotime

oflongerarticles inthe generalfieldofsoilclassificationand morphology.Stephens and Donaldhave prepared an account ofthesoils ofAustralia

andhave gone furtherthantheauthorsofsomeother papers ofthistype

bydiscussingcrop responsestomajorandminorfertilizerelementswhichhave been spectacular because of the unique character of certain defi-

ciencies therein

AnnArbor, Michigan A G NORMAN

November, 1958

IN THE GREAT PLAINS

COORDINATEDBYR V.OLSON

III Pasture and Range Crops by JACK R. HARLAN 15

VII. Wind Erosion Problems byW. S. CHEPIL 56

BEHAVIOR AND FERTILIZER USE

BYWERNERL.NELSON AND GEORGE STANFORD

II Diagnostic Techniques as a Guide 73

V. Time of ApplicationandResidualValueof Fertilizers 100

BY E C.STAKMAN ANDH A.RODENHISKH

I. Why Race 15B Is Notorious 143

V The ExplosiveSpread and EstablishmentofRace 15Bin1950-1951 146

VIII Vicissitudes in Breeding Rust Resistant Wheats in the Past 149

X. TheVirulence of 15B for Previously Resistant Varieties 152

XII Increased Complexity in Physiologic Races of Wheat Stem Rust Since

XIII. Race 7of Oat Stem Rust Also Explodes in 1950 158XIV Shifting Populations of Physiologic Races of Other Pathogens,Especially

III. The Australian Soil Landscape 173

IV. History of Fertilizer Use in Australia 200

VI Deficiencies of Other Major Elements 216

CASTORBEANS: A NEW OIL CROP

FOR MECHANIZED PRODUCTION

BY LEROY II.ZIMMERMAN

II. Mechanisms of Ammonia Sorption 326

III Reactions of Ammonia with Soil Constituents 327

IV Nonbiological Oxidation of Ammonia 335

V Factors Affecting SorptionandLoss in the Soil 336

VI Effects ofAmmoniaonSoil Propertiesand Organisms 342

NEW GRASSES AND LEGUMES FOR SOIL

AND WATER CONSERVATION

BYA L 1 1\FENRICHTER

THE ROLE OF SULFUR IN SOIL FERTILITY

BYHOWARD V.JORDAN ANDL E. ENSMINGER

II. Role of Sulfur in Plant Metabolism 408

V Removalof SulfurfromSoils 421

VIII. New Developments May Change the Supply-Requirement Balance 430

CORN PLANT POPULATION IN RELATION

TO SOIL PRODUCTIVITY

BY G H DUNCAN, A L. LANG, AND J. W. PENDLETON

Page

III PlantsGaininGrain-ProducingEfficiency asPopulationIncreases 440

IV Populations Which Give Maximum Grain Production on Soils of High

VI. Changesin Plant Characters Associated with Higher Population Rates 451

VIII. OtherFactors AffectingOptimumPlantPopulation 465

II Principles Relating to Liming Soils 476

IN THE GREAT PLAINS

II FieldCropsbyE.C.HEYNE

A Field Crops of the Region . 8

1. The Utilization ofForage by Ruminants . .21

5. The Properties of Grass Seeds . 22

6 BetterWaysofGetting Stands 22

V Soil FertilityProblemsby H.F. RHOADES

1 Losses from Dryland Soils 37

2 LossesfromIrrigated Soils 38

1 Relation to Kind of Soil 39

2 Relation to PastCroppingandFertilizer Practices 39

D Status ofOtherNutrientElementsinGreatPlains Soils 41

H Factors Influencing the ResponseofGreatPlains Cropsto Nitrogen

VI. IrrigationbyH R. HAISE

A INTRODUCTIONThe GreatPlains of the United States constitute a large segment of

nearlylevel togentlyrollingland interspersedwithsomeroughways and some sand dunes The area extends through the center of thenationfromtheCanadianborderto southern Texas.It isboundedon the

drainage-westbytheRocky Mountainwatersheddivideandincludesa largeportion

of tenstates. The exact easternboundary of theGreat Plains is not welldefinedandhas beendelineated invarious ways In general,this bound-

ary approximately corresponds to the zone separating the true prairie,dominated bytall and mid grasses, from the mixed prairie of short and

from thosewhich donot Thearea currently recognized by the U.S partmentofAgriculture1

De-tobetheGreatPlainsareaisindicatedin Fig 1.

It is thisareatowhichthediscussions in thischapterpertain

The GreatPlains area provides a tremendous forcein American

these statesproduce about 60 per cent of our wheat and 35 per cent of

ourcattle.

Since its settlement byadventurous easterners, for the most partlessthan one-hundred years ago, the Great Plains area has been confronted

stemmed primarily from periods of drought, intense winds, low prices,and overproduction, interspersed withperiods offavorableclimate, high

being

Duringperiodsoffavorableweatherconditions there hasbeena

tend-ency for new land to be plowed from its native grass. Throckmorton

(1955) has estimatedthatalmost ninemillion acres ofgrasslandandother

1

FIG 1.TheGreat Plains areawith normal annualprecipitation in inches (

period 1944 through 1955.Almost anequal acreageofland was returned

be-tween weatherconditionsandchangesingrasslandacreages.Forinstance,

re-vegetated In1955,adroughtyear,onlyabout300,000acreswerebroken

while about650,000 were revegetated either by reseeding orby natural

revegetation

During theearlier history of the GreatPlains there was an influx of

settlers in favorable years. Farmers and investors accustomed to more humid conditions placed a high value on land, which caused high landand manynon-resident or"suitcase" farmers Inless favorable pe-

riodstherewasan exodusofpeoplewhichresulted inlandabandonment.Theonlypeoplewhoremained were thosewho haddevelopedstable sys-

temsoffarm and ranchmanagementorthosewhowerefinanciallyunable

tomove

For the past twenty years many efforts have been made to stabilize

have been established and agricultural researchhas been intensified. In

1935 the Great Plains Agricultural Council was established, initially volvingonly the southern Great Plains This council meets at least once

in-annuallyandiscomposedof representatives ofallstate andnational

been responsiblefor manystudies and reports on Great Plains problemsandhasbeeninstrumentalinpromotingagriculturaladjustments,research,

andgovernmentalactionprograms

Theimpactofefforts to stabilizeconditions inthe Great Plains isginningtobefeltinmanyways.Thebestillustration ofthisfactliesinthe

be-comparative economicandsocialeffectsofthe droughts ofthe1930's and

the 1950's. Whilethelatterdroughtdid notaffectas largean area as theformer,in manyareasit was moresevere Yet, partlybecause of agricul-

govern-mental programsandfavorable economicconditions in the nation ally, the effects of the drought of the 1950's have not been nearly as

gener-severeasthoseofthe1930's.

To many,thesolution to theproblemsoftheGreatPlains hasseemed

tobe toreturnallthe land to grass and to convertfully to a range

fertile land capable ofproducing yields of40 to 45 bushels per acre in

exceptionally favorable years the solution seems quite different. This

farmerfeelsthatmuchofthe landintheGreatPlains is better suited for

wheat production than anyother area oftheUnited States and thatlimited production shouldbepermittedinthe yearsthat arefavorablefor

un-crop growth Undoubtedly many cultivated areas of the Great Plains

shouldbe revegetatedinthe bestinterests ofall concerned.Italso seems

likely,however,thatthereisapermanentplaceforthe grainandlivestock

farmerwhoisa carefulmanager and who willbuild upreserves in good

yearstocarryhimover the unfavorableseasons

The problems mentioned above indicate the great need for

in thefieldofagronomysince theproblems are so closely related to theproductionof cultivatedandrangecrops.In thelater sections ofthischap-

ter the authors point out specific agronomic problems and the present

B CLIMATE The averageannual temperature andnormal amount of precipitationfortheGreatPlainsarea areshownin Fig 1 Itcanbeseenthattempera-

rain-fall islow throughoutthePlains.Thornthwaite(1941)classifiesthe easternpartofthisareaasnormallyhavinga drysubhumidclimatictypeandthe

westernportionasbeingsemiarid

Becauseof variations inthemovementofmoistordryandhotorcoldairmassesover theregion,theGreatPlains areaissubject toextreme cli-

maticvariations.Theseare evenmoredetrimentalto agriculturethanthe

lowaveragerainfall. Tropicalairmasses, whichnormallyflownorthward

over thePlains and meetcold airmasses, usually comefrom thedry

pla-teau ofMexico and result in little precipitation Occasionally, however,

moistairfromtheGulfofMexicoswerveswestwardfrom itsusual easternpath, resulting in heavy precipitation in thePlains. Accordingto

north-Thornthwaite (1941) severe rainstormsanywhereinthePlainsmaybring

afifthinasinglehour.Onthe otherhand,periodsaslongas120daysmay

occur duringwhich norainfalls. Hailstorms arealsocommon during thesummer months Precipitation throughout the area is greatest in spring

Extreme variations inannualprecipitationoccur tliroughout the area

Palmer (1957) has classified the year-by-year climate for 60 stations in

theGreatPlainsover aforty-yearperiod accordingtoclimatic types.Data

forfiverepresentativelocationsareshowninTableI.Thesedataillustratethe greatvariability of climatic conditions At each location the rainfallsurpasses that ofa semiarid climate frequently enough to encourage thedevelopment of a cultivated agriculture Ensuing periods of semiarid oraridclimatemay provedisastrous to agriculturalendeavors

completewithoutmentioningwind movements which hasten

about 8.5 miles per hour at a 2-foot height Velocities of 28 miles perhour for a duration of one hourmay be expected every two years and

TABLE I

Climatic Variability atFive LocationsmtheGreatPlains' 1

Percent of yearshavingindicated climatictype

Data fromPalmer (1957).

every fiftyyears Thelevel of atmospheric wind movement tends to be

higher during periods of drought than during periods of favorable cipitation.

pre-C SOILS

TheeasternedgeoftheGreatPlainsregionas definedin Fig.1 closelycorresponds in thenorthern portion to the eastern edge of the Chestnut

(Brunizem) soilsandthe Chernozemsoils. In theSouththisline followsthe eastern edge of the Reddish Chestnut soils. The western portion of

theGreatPlains region,wherelowerrainfall conditionsexist, hasBrownsoils occupying most of the area with Reddish Brown soils occurring in

Texasandthesouthern partofNewMexico All ofthe zonalsoils oftheregion thushave developed under lowrainfallconditionsandhave a cal-

cium carbonate accumulation zone at some point in the soil profile. Ingeneral this zone is formedcloser to the surface as the climate becomes

drier. In fact, soils in the extreme western portion may have calcareoussurfacehorizons

In additiontothe zonalsoils,severalazonalandintrazonal soilgroups

exist throughout theregion. Wide belts of alluvial soils occur along the

ThesoilsoftheGreatPlains have developed froma variety ofparent

and sandstones form parent materials for soils in various places, Thorp

et al. (1949)havediscussed the parentmaterialsandsoilsofthe northern

Great Plains in more detail and North Central Regional Publication 76

(1958) describes thesoils inthe fourGreatPlains states inthat region

information hashinderedthis practice. As of January 1, 1957, therewere

only 18counties intheGreat Plainsareawith completedrecent standard

Departmentof Agriculture in 1956began acceleratingits soil survey

ac-tivitiesoverthesouthern half oftheGreatPlains wherethe most critical

Because ofthe nearly level togently rollingtopography of the Great

exist, the greatestportion of the Plains has surface soils of finertextures

fields mayhave only one or two soiltypes present Data taken from the

1954CensusofAgricultureshow that 83.2per cent ofthe land ofthe

showa higher portionofthelandascroplandsincemostareaswestofthe

land

II Field Crops

E. G Heyne

Kansas State College,Manhattan, Kansas

A FlKLD CROPS OF THE REGIONThequestforgoldinthesixteenthcenturybroughtCoronado intothe

Southern GreatPlains This "gold"wasdiscoveredintheform ofthefieldcropsoftheGreatPlains inthe nineteenthandtwentiethcenturies Itcan

be mined every year, generally in profitable quantities, and should be

con-tinuedbecause of parallelprogress in bettersoil management, improvedfarm anduse of and Each of

these threesubjectsisaninterestingdevelopmentas pertainingtomodernfarminginthisregionbutonly afew commentswillbemade onthelatter

subject

Allthefieldcropsthathavebeengrownornowarebeing producedintheGreatPlains are plant introductions Most ofthe areawas originally

covered withtall grasses intheeast which give place to short grasses in

not toosandy have beenturnedbythe plow Weareawarethattoomuchmarginal land hasbeen broken fromthe nativevegetation.However,many

ofthese areashave provedsuitable forthe productionofdrought-resistant

humid area, and alternated with fallow in the drier andmarginal areas

SomeoftheseimportedcropsgrownintheGreatPlainsincludecotton,

broomcorn), themillets, alfalfa, swcetclover, field peas and beans,

Wheatisgrownthroughouttheentire region;cottonand sorghum

areaimmediatelynorth,cornand wheatinthecentral portion,andwheatandflaxare perhaps themore important crops in thenorth At one timenorthwesternKansaswasthelargestexport centerofcorninthat stateand

the nearby areas of northeastern Colorado and southwestern Nebraska

cen-tral Nebraska, especially under irrigation, and is grown as far north as

Montana Sugarbeets thrive under irrigation in Colorado, Montana,

Wy-oming,Nebraska, andKansas.Alfalfadoes wellthroughoutthe region onboth drylandandunderirrigationandinyearsoffavorableweathercon-ditions, large quantities ofseed are harvested in Oklahoma, Kansas, Ne-

College text books on field crops (Martin and Leonard, 1949) give

moreinformationthanadequatelycanbepresentedin thisdiscussion.The

tenGreatPlains stateshave anabundanceof cultivated acresandproduce

of United States acreage and production of some of the important fieldcropsofthe tenstates in which theGreatPlains arelocated are given in

TableII.In the ten-year period 1945-1954, overhalf ofthenation'swheat,

sorghum, andflaxandaboutone-thirdormoreofthe alfalfaseed, cotton,

barley and sugarbeets were produced in this region Acre yields werelower thantheUnitedStatesaverageascanbe observedincomparingthepercentageofUnitedStates acreagewiththe percentageofproduction In

is whatmight beexpectedinanareawheredrought isa continuous duction hazard Large scalefarming and modern machinery tend to de-crease per acrecosts ofproduction.Evenseedcostsareless.Forexample,20

pro-to30Ib. ofwheataresufficientto plantanacrein someparts ofwestern

Kansas whereas in the more humid areas as much as90 Ib. of seed areneeded Detailed changes in important crops by counties is given by Weaver (1954) forNorthand SouthDakota, NebraskaandKansas

TABLE Jl

inComparisontoTotal UnitedStates Production, 1945-1954a

Production

Asmanyofthesecultivated acres aremarginal lands, the percentage

ofabandonmentishigh.The abandonmentofwheatinthe regionduring1945-1954 averaged 12.3per cent whilefortheremainingwheat landsin

theUnitedStatesitwas5.6percent.Thesefigures forcornwere2.3and

per cent respectively Abandonment figures for the drier areas of the

GreatPlainsare For insomewestern Kansascounties

farmers harvested only6 to 8 acres ofwheatfor every 10 acres planted

during 1916to 1952

the kinds offield crops being produced now (1957) are perhaps fairly

whereadditional irrigationisdeveloped but even underthese conditions,

prospectsofintroducingentirelynewcropsintothe region are smallwith

the present informationwe nowhave onothercultivated crops

The twocropsthatpredominateintheGreatPlains area, asmeasured

bythe percentageofthe cropproducedintheUnitedStates,aresorghum andwheat Ninety-three per centofthe grainsorghum, 87per centoftheforagesorghum,and62per centofthewheat grownintheUnitedStates

wasproducedinthetenGreatPlains states during the period 1945-1954

Bothofthese crops areadaptedforgrowinginthesemiaridregiontypical

oftheGreatPlains.In the southernpart,wheatisgrownas a winter crop

andinthe northasa springand summercrop,althoughinMontanawinter

wheatisnowalmostasimportantasspring wheat. Sorghumisa short-dayplantandrequires hightemperatures. Themostfavorabletemperature is

about 80 F withaminimum of60 F.Therefore this cropisbestsuited

tothesouthernhalfoftheregion.

B SORGHUMS Sorghums followed the earlier settlers into the Great Plains During

they had produced. Normally we do not use sorghum for food but in

Nearlyall ofthesorghum grain andforageproduced inthe GreatPlains

uses

thekindsfirstintroducedintotheUnitedStatesweretallandlate to

ma-ture. Thekafirsandmilos,however, producedsatisfactory grain crops inthesouthern partofthe regionbut becauseof latematurity they could not

begrownwithmuchsuccessanyfarthernorth thanKansas (Fig 2). The

madefromtheseoriginallyintroducedvarietiesgaveearlierand somewhat

wheat The oftheearlier varieties

extendedthe area of grain sorghumproduction northinto Nebraska and

higheraltitudes ofKansasand Colorado (Fig 2). Suchvarieties asEARLY

KALO, GOES, SOONER, COLBY,and DAY were responsible forthis expansion

RECENT ADVANCES (1948)

Plains regionduetobreedingearlymaturingvarieties.

ingofadaptedgrainsorghumsinSouthDakota,particularlyNORGHUMand

RELIANCE,extendedthe areaof

grainsorghumstillfarther north (Fig 2).

Theresults ofsorghumbreedinghave extended the areaofadaptation of

Initspresent areaofadaptationsorghumfurnishesanalternativecrop

togrowwith cottonintheCaprockareaofTexas andwithwheatinotherareasof the Great Plains Sorghums respond well to irrigation and

wellon sandysoils where wheatdoes poorly.Duringthe lastthirtyyears

sorghumvarietieshave beentailor-madetofitlarge scalemodern farming

ofgrainsorghums for1957 wasestimated at481millionbushelswhich is

nearlydoublethe previous record cropof 1955.Eveninthewheatstateof

Kansas, sorghum exceeded all other cereal crops in grain production in

1957

Moisture generally is the limiting factor in crop production in the

GreatPlains The lackof suitable moisture in thefall of 1956 prevented

accountsfor alargepart of the record grain sorghum crop in 1957 Thisillustrates how wheat and sorghum can be interchanged readily where

thesetwocrops are adapted.

Hybrid sorghums are the latest development in this crop It is notknownwhether the areaof sorghum adaptationwill be extended by hy-

thathybrid sorghums developedmore rapidly early in the season under

cool growing conditions and reached the blooming stage earlier thanstandard varietieswhich were thought to be of the same maturity.

Wheathas been grown formanyyears in theUnited States (Salmon

ct al., 1953) but not until two introduced varieties, MARQUIS hard redspringandTURKEY hardredwinter,cameintotheGreatPlains werethere

wouldnot bea successful cropforKansas That statement was based on

experiments conductedwith spring andsoft wheats TURKEYwheat came

Men-nonites emigrated from southern Russia to central Kansas, bringing this

GreatPlainsand rapidly replaced thespringwheatvarieties andthesoft

wheat varietiespreviously available There isprobably no TURKEY wheat

as such being grown in theGreat Plains area now (1957) butthere are

such as TENMARQ; and many grandchildren such as PAWNEE, COMANCHE,CONCHO, WESTAR, andWICHITA beinggrown on farms intheregion. YOGO

wheat areafarther north in Montana It alsohas TURKEY in its pedigree

FIFEwheatsand BLUESTEM andselections ofthesevarietieswere grown

the spring wheatarea 1900 but not was

cluccdfromCanadain 1912 wasthere asatisfactory springwheatvariety

forthenorthernGreatPlains TheadvantagesofMARQUIS wereearly

ma-turity,highyield,andexcellent quality.Theearlymaturityaidediningdamagefromtherustsandalsomayhave accountedforits ability to

escap-performwellunder droughtconditions.Whererustisnotaseriousannual

problem, as in certain areas of Montana, MARQUIS is still being grown.MARQUIS has been used widely as a parent and such varieties as CERES,

THATCHER, MIDA,REDMAN, and morerecent varietiessuch as LEE,RESCUE,

andSELKIRKallhavethisvariety in theirparentage

MARQUIS andTURKEY wheatsshouldbegivencredit forthe wide-scaleproductionofwheatinthe regionandforitssettlementbyfarmers.Germ-plasm of these varieties has been interchanged as many of the hardredwinterwheats trace theirparentagetoTENMARQ whichhas a selection of

TURKEY and MARQUIS for its parents KANRED, a selection of TURKEY, also

occursin the parentageofTHATCHER whichin turn has been extensivelyusedinthebreedingofhardred spring wheats

D PRESENT PROBLEMS AND FUTURE POSSIBILITIES

Moisture will always be a major problem in the Great Plains Plantbreederscannot produceplants that willgrowwithoutwater Underbothdryfarming and irrigation, field crop productionis intimatelyrelated tomoisture conservation through proper soil management practices Con-

tinued research directedtoward theutilizationof wateris essential.

Duringthelast fiftytoone-hundredyearsoffarmingintheregion,thecrops bestadaptedto local areas have been selected Inspite of the de-sirability of growing other crops, farmers in some areas depend almost

thatthere arenoother cropsthatcanbesubstitutedsuccessfully forthosenowbeing grownintheGreatPlains.This docsnot exclude the possibili-ties thatother cropsmay be found or developed that will compete with

thosenowgrown.Thereforesomeemphasisshouldbe placed on researchdesigned to develop or find new crops adapted to the region. However,

and sorghumproduction these crops should receive concentrated researcheffort.Thiscanbe done bybreedingbettervarieties,improvingsoilman-agementpractices,anddevelopingbettermechanicalprocessesofproduc-

tion.

There are certain limitations concerned with breeding better fieldcropsforsemi-aridregions Theplantbreeder'smethods are no different

thanthe procedures thatoccur undernatural evolution Wheat and

sor-ghum werealready adaptedto droughtconditionsbefore manattempted

tomake Further progress along lineean be

to beslow It ismuch easier tochange plantswithrespect to characters

characters ofa complex physiological nature suchas drought-resistance,

winter-hardiness or,forexample,to develop asorghum that willgrow at

aminimumof50 F.insteadof60 F.Thesepresentproblemsshould notdiscourage research along these phasesofbreeding.However,atthepres-entadequateinformationis notavailable toattacktheproblem of breed-

and studying segregating populations under the natural environment.Scientificresearchin agriculture forfuture progressprobablywillpass

through three phases beforeresults canbe transferred to the farm Basicresearchcomesfirst.Thisisaslowunspectacularprocess. Plantstudies of

a basic nature need immediate attention Applied research, the second

phase,isentirelydependentuponfacts obtainedfromstudies of a

funda-mentalor basicnature In general,most experimentstations andcolleges

intheGreatPlainsarc;wellstaffedtodothis job. Theyarc alsoequipped

to carry out the third phase,which is the bringing of practical results of

scientificresearch tothefarm throughadult education

We are fairly certain that winter cereals produce better than spring

wheat, rye, barley, and oats should increase their production potential

However,progress hi this directionis being made slowlybecause of thelackofbasicresearch Thefuture progressin field cropproductioninthe

Great Plains primarily will depend on facts obtained through basic

fieldsofplantandsoilscience.As wecontinuetobecome morespecialized,

itbecomes moreimperativethatwehave an adequateoverallcoordination

of these researchteams Whether progress comes fromstudies related to

wateruseorbybettercrop varieties is not important It is evident,

tomaintainingandincreasing theagricultural outputoftheGreatPlains

Jack R. Harlan

U.S Department of Agriculture

A PRESENT SITUATION

1. Range ConditionSouthern Texas and the southern Great Plains appear in 1957 to be

themostsevereandintense record Formuch

16 JACK

ofthe area theGreatDroughtofthe1930'swasnot nearlysosevereas the

Great Drought of the 1950's. Theextreme deficiency in precipitation peared to move northward as the years advanced At the present time,

Kansas and Colorado forfour to five years, and parts of Nebraska have

experienced a two-to three-yeardrought Tothe northward, the western

droughtin 1956 In general, however, conditions have been favorable intheNorthernPlains foranumberof years

Despite theextreme droughttowhichmostofthesouthernGreatPlains

have beensubjected, arecurrenceofthe widescalefinancial distress and

reasons for this. The prices offered for agricultural products have been

efficient; thedevelopment of industry and associated enterprises has fered part-time or full-time employment to farmers and ranchers in dis- tress; but perhaps more important, farming practices are far moreadvanced today thaninthe 1930's. Due toa large extent toresearch and

of-extension programs, themodernfarmer andrancherisdoingamuchbetter

job today thanhedid twentyyearsago

On the other hand, strongpricesandanarrow marginofprofitonstockluive tended toencourage heavy stocking during a critical drought

condi-tion throughoutthe southernPlains The enormous increase in brush onTexas and Oklahoma rangelands cannot be blamed altogether on either

the recentdrought oreconomicpressures Rather, it is thefruit of a half

century or more of chronic overgrazing and mismanagement. The trend

towarddegradationofrangeconditionwassharply accelerated inthelast

thrive, thedeterioration in range condition has been just as great if not

In thecentralandnorthernGreatPlains,conditions are generallymuch

havebeen temperedbytheneedforwinterforage,andthe generallylowerland valueshave eased the pressures formaximum per acre production.Thenorthern rangelandshave for ofthelivestock

industry Thesouthern rangelandswillneedtoproduceadditionalforage

in orderto accommodateany significantexpansion.

2. Revegetation

Extensiveabandonmenttook placethroughouttheGreatPlainsduringthe 1930's. In the northern Great Plains a very high proportion of the

abandonedfarmlandswasseededtocrestedwheatgrassinthe late1930\s

degener-ated in condition and productivity, the major task of revcgetation was

continuinganda comparatively small proportion of the acreage has beenseededtopermanentgrasslands The reasonsforcontinuedabandonment

are primarily the greaternumberofsmallholdings,thegreater erodibility

adaptedseed,theproblems encounteredinhandling, marketing, and

Thereisnothing available inthesouthern GreatPlains comparable to

been withnativegrassesandtheseedsupplieshave beenerratic (Harlan,1955).Thegreatestacreageshave been seededto"mixedbluestems,"sand

side-oatsgrama, andindiangrass inapproximately that order Exceptfor sand

lovegrass andswitchgrass, mostof thisseed has come fromwild harvests

(Hooveretal,1947) Seedisproduced onnativestands inabundance in

someyearsandverylittle isproduced inotheryears. Therehas notbeen

a good mixed bluestem harvest since 1950 and the last really large one

butthe sourcevariesfromyear to year Thedifferentsources givewidely

sidr-oats gramaandtoa lesserdegreetowestern wheatgrass Thebulkof the

es-tablishedtothesegrasses.

Standestablishment generally is more difficult in native grasses than

require protectionintheir early stages Drilling intoasorghumstubbleor

residue has been the most satisfactory method Seedings on other

seedling vigorbut canbe seeded inthefallor veryearly springand will

growat cool temperatures This the a decided

competitive advantage over weeds and permits the use of fallow, smallgrain stubbleorevenweed-coveredseedbeds

Mostofthe nativegrassseeds are chaffyanddifficulttohandle.Routine

analyses required for interstateshipment orfor seed trade channels areverydifficultand expensiveto conduct (Harlan, 1957). Laboratory timerequiredtorunasingle puritytestonalotofchaffy seedisfrequently in

not reproducible If the seed cannot beblended, representative samplescannotbedrawn.Even skilledandexperiencedanalystsfrequently obtain

widelydivergentresultsfrom thesamesample.Asaresult, manyof theseseeds are refusedbytheseed tradeandmostofthemovementisthrough

"over-the-fencc"transactions

marketing procedures, uncertainty of obtaining good stands, and erratic

performancesof strainsfromdivergent sourcesall havecontributedtothegeneralfailure ofthe rcvegctationeffort.

3. Altitudes and Pradices

andbreedingandtotheappearanceofthe animals Relativelylittletionhasbeen paidtotheactualperformanceof the animals,theirrate of

support thelivestock.Theideathatarancher shouldand must bea grass

growerfirstanda stockgrower second isa novelanduncomfortablecepteven for someofthe leading ranchers of theregion. It has been, in

con-fact,anunpalatable idea tomany agriculturalleaders including researchworkers, technicians, extension workers, and some administrators Yet

them

Recentyearshaveseensome markedchangesintheserespects.

Ranch-ersarecoming more and moretoknowtheirrangeplantsand tolookfor

changes inbotanical composition thatindicatetrends inrange condition

Theyarelookingmoretowarduseofsupplementalpastures asameansof

lightening the grazing load at critical times Some have learned to work tamepastureprogramsinto theirranchingoperationsand moreare grow-

ing additional hay, stover, grain, and silage toround out their feed

re-Manyranchers understand better the valueof deferment of

rangeland andtheneedforproduction ofsurplusgrass inmoderate

graz-ing.Thereisamarkedtendencyforstockmen tothinkintermsof specific

homogenized green materialwithwhichnature covers the countryside.

The modernrancher isnot only becoming more ofa grass expert, he

is becoming chemical-minded Horn flies, grubs, lice, ticks, and screwwormsarebeingcontrolledmuchbetterthaninformeryears.Weeds andbrusharebeing sprayed on an extensive scale in some areas Stilbestrol

implantsandantibioticsarecommonlyused,andprotein supplementsaremuch more skillfullyused than formerly. Ranchers are intrigued by thepossibilities of animal and planthormones, systemic insecticides, antibi-

otics, and otherwonders of the world of chemistry They are eager for

newdevelopmentsandquicktotakeup newpractices.Moreofthemhave

ofthe physiologyandclinical aspectsinvolved.

Theagronomistandtheanimalhusbandmanhave,inshort,amore

twentyyearsago, and moreconcrete research resultswill be expected in

the years to come This will demand closer coordination between theagronomistand the livestockspecialist, a higher order of research, more

basic andfundamental researchintothenature of growth and

partof the extension man All of this is to the good of agriculture andshows thatsmall advances breeda demand forstill greater progress

Studiesin thenorthern GreatPlainshave shown that certain types of

rangeland respondprofitably tonitrogenfertilization (RoglerandLorenz,

1957).These ranges are primarily along theeast side oftheGreatPlains

where western wheatgrass and the stipagrasses are dominant Farther

west where blue grama becomes the dominant grass, responses are not

suf-ficiently tonitrogenous fertilizers to payfor the fertilizer (Mader, 1956;

Brouse et al,1954) It is

rangelands occurs where thetotal soil nitrogen is high The cool-season

nitro-gen from nitrification under the low soil temperatures that exist in the

20 JACK

The acreage of irrigated pasture is increasing slowly throughout the

Groat Plains. Some combinations are remarkably productive and even

small acreages can supply significant amounts of forage Small grains,sudangrass, andbermudagrass withladinoclover orhairy vetch areespe-

ciallyproductiveinthesouth Bromegrass andalfalfaare the most

Ken-tuckybluegrass, red andalsike clovers, areused toa limited extent

Irri-gatedensilage crops havea considerablepotential throughout the Plains

inproviding substantial quantities of energyand roughageforincreased

Studies onirrigated and subirrigatedpastures and meadows out the Great Plains area have shown that significant and profitable in-

al., 1954) with tame forages such as bromegrass, alfalfa, alsike, and red

clover

3. Supplemental CropsThemostefficientuse ofnative rangelandis now beingmade in con-junction withsupplementalpastureandforagecrops. Smallgrain pasture

supple-mentstonativerangeinthecentralandsouthern GreatPlains Thesmall

indus-try and muchof the sorghum grown has been a compromise between a

have been established exclusively forgrazingon alargerscale, and more

sudangrass and forage sorghums are grown entirely for livestock feed.

Brome-alfalfa and crested wheat-alfalfa pastures in the North and

ber-mudagrass and blue panicin theSouth are nowbeing worked into

4. Weed and Brush Control

Brush control is a problem of enormous magnitude in the southern

has been weakened by drought or overgrazing (Mcllvain and Savage,1954) Brush control is not new, but moreof it is being done than everbeforeandinsomeareasbrushisactually beingsetbackfaster thanit is

vestedcan oftenbe obtainedfrom sprayingweedswith a herbicide than

from anyotherbrushcontrol practice

Nordan crested wheatgrass recently released in the northern Great

1954a, b) Its large seed and exceptional seedling vigor give greater suranceof successfulstands and maywell permitmore flexibilityin land

as-use.Therecentdevelopmentofimprovedvarieties ofnativerange grasses

inNebraskaand Oklahoma mayhave an evengreatereffectontheover-all

revegetation picture Those adapted to the southern Great Plains

espe-cially,maygoa longwaytowardsolvingthe chronic seed shortageaswell

as many ofthe handling, marketing, testing, and labeling problems that

havehelduptherangeseedingprogram forsomanyyears (Harlanetal.,

Old Worldbluestems,and someofthe lovegrassesare findingaplace,and

insouthernTexasbuffelgrassisbeing used on rangelandaswellas intame

pastures

C RESEARCH PROBLEMS

Boththeimprovementofforageplantsandthedevelopment ofbetter

managementpractices will depend to a large degree on a better standing of how they are used and what constitutes good forage Low

under-gains are often obtainedevenwhen ampleforageis available The

situation.

2. The Revegetation of Degraded Rangelands

Reasonably satisfactory methods are available for establishing range

Savage, 1954).Therearemillions of acrestoo rough, toostony,or tooliedanderodedto cultivate.Manyofthese rangeshave been overgrazedto

gul-the pointthatdefermentwillnotrestorethem inanyreasonable length of

inGreatPlains agriculturetoday Special plantstrains areneededthat are

so aggressive under these conditions that they can become established

withouta seedbedand thrivesufficiently to at leaststarta succession

to-wardrecovery. Research along theselines is being conducted onthe Old

3. Control of Woody PlantsPresent methods often cost 12 to 16 dollars per acre for partial andtemporarycontrol ofbrush onlandthatunder idealconditionswill yield

nomorethan60Ib.ofbeef peracre Thoughthepracticesometimes pays

for itself in increased production, there is no over-riding incentive evenwitha government subsidy on the practice. Better methods are neededandsufficientworkhasnowbeen done on theproblemthatfuture prog-

4. Grass Seed Production

Withthe increasein irrigatedacreagethroughoutthePlainshas come

ademandformore high returncrops. Grass seedisa potentialcash crop

ofhigh value andtheproduct is in great demand forrange andpasture

seedings (Harlanet al., 1956) Studies underway have shown that high

amend-ments, watering regimes,harvesting, cleaningandprocessing procedures,

5. The Properties of Grass Seeds

Appropriate proceduresfor testingandlabelingmanyrangeseeds are

notknown (Harlan, 1957). Optimumtemperature andlightregimes,

ger-mination media,methods ofbreaking dormancy, methods of determining

beenworkedoutforanumberof species. Thenatureanddurationof

dor-mancy,conditionsfor optimumseedling growth, theeffect ofvarious greesofprocessingongerminationandfieldperformancearc areastotally

de-unexploredformanyoftherangeplants

6. Better Ways of Getting Stands

Standfailures inrangeseedings areextremely costly.The seedis allyhigh pricedinrelation tothelandvalue,andtimelostin failuresmay

isspent preparing a seedbed Twoadditional years may belostin

deter-mining whetheror not a stand was obtained Afailure requires thatthe

seedshavesprouted, grasshoppers, competitionwith weeds, etc. Many of

these solved withinformation intensive

re-search on stand establishment may reveal more efficient practices than

thosenowin use

7. Breeding Behavior of Range GrassesProgress has been madein improving both native and exotic grasses

understandingofthegenetics, cytologyandcytogeneticsofthespecies inquestion (Hanson andCarnahan, 1956) More basicworkalso is needed

inthe areaofphysiology and ecology insofar as there are under genetic

control

8. Breeding and Improvement of Grasses

of superiorforage varieties. Greater assurance of obtaining stands may

comewith the developmentof grasses withlarger seed size and greater

seedling vigor (Kneebone, 1956; Kneebone and Cremer, 1955; Rogler,1954a, b) Some seed production problems couldbe solved by varietiesthatgive higher seedyieldsunder cultivation andwhich are resistant to

andthedevelopment of varieties withless new-seeddormancy coulddo

muchtoreduce the technicaldifficulties of seedhandling and marketing

aswellas improve thechances ofestablishment Hardier and more

per-sistentvarieties better suited to survival and propagation under grazing

coulddo muchto reclaimdegradedrangeland

J C. Hide

A INTRODUCTION

pro-duction,andindustrialexpansionismost frequentlylimited bylowture supply For more intensive utilization, moisture conservation must

mois-receivehighpriority.People'sopinionsdifferas towhatthetermmoistureconservationmeans, buttheywouldgenerallyagree thatmoistureiscon-servedwhen:

1. Theproportion of the precipitation available for transpiration by

plantsisincreased

2. The amountof usefulplantproductsproducedperunit of moisture

3. Moistureabovethefieldcapacityoftherootzoneof plantsispassed

throughthesoil andcontributes topermanent undergroundreservoirs or

tostreamflow

TheGreatPlainshave been occupiedbywhitemanfor50to100years.

During this time, his major contributions to moisture conservation havebeen (1) the introduction ofbetter-adapted crops, (2) improved control

ofweedsthatcompete withcropsformoisture,and (3) mechanizationto

timely tillage operations The latter item probably contributes more to

manpowerefficiencythan towater-use efficiency.

whereit falls,sincethis isinagreement with currentpractice intheGreat

tillage usually known as dryland farming, much of the information sented canbeappliedtothe extensive areasofrangelands

pre-B PRESENT SITUATION AND PRACTICES FOR MOISTURE CONSERVATION

summer-fallowfrom23 drylandstationswhichwereoperated over theGreatPlains

bythe U.S Department of Agriculturein cooperation withthe State

Ex-periment Stations In summarizing the data, Mathews and Cole (1938)found an average storageattheendofthe fallow period ofonly20to25

per cent of the precipitation that fell during the fallow period Thysell(1938) foundthat at Mandan, North Dakota, therainfall duringthe ap-proximately20-month fallow periods ending aboutApril20 of the years

1916 to 1934 variedbetween 16.67 and31.58inches Water stored in thesoilduring these fallow periods variedfrom1.01 to9.07 inches.Thesecond

thelowest moisture storagehadalmost averagerainfall.Thusthereisnot

moisture storageefficiencyisduetothehighproportion ofthetotal

by Robb (1938).Thesedataforthewesternthird ofthestateare typical

onceaweek, but 60 oftherains one-fourth inch orless