Title theory Agro123 (new)_compressed.pdf ✅

CollegeOfAgriculture,Darwha TheoryNotes On CourseNo :-AGRO123(1+1) CourseTitle:-Fundamentalsof AgronomyII Semester :-II(New) Q.1.DefineIrrigation.Statetheroleofwaterinplantslife. Irrigationisdefinedastheartificialapplicationofwatertothesoil forthepurposeofcropgrowthorcropproductioninsupplementto rainfallandgroundwatercontribution. Roleofwaterinplants. A)Physiologicalimportance •Theplantsystem itselfcontainsabout90%ofwater •Amountofwatervariesindifferentpartsofplantasfollows o Apicalportionofrootandshoot>90% o Stem,leavesandfruits-70-90% o Woods-50-60% o Maturedparts-15-20% o Freshlyharvestedgrains-15-20%
•Itactsasbasematerialforallmetabolicactivities.Allmetabolicor biochemicalreactionsinplantsystem needwater. •Itplaysanimportantroleinrespirationandtranspiration •Itplaysanimportantroleinphotosynthesis •Itactivatesgerminationandplaysinimportantroleinplantmetabolism for vegetativeandreproductivegrowth •Itservesasasolventinsoilforplantnutrients •Italsoactsasacarrierofplantnutrientsfrom soiltoplantsystem •Itmaintainsplanttemperaturethroughtranspiration •Ithelpstokeeptheplanterectbymaintainingplant’sturgidity B)EcologicalImportance  Ithelpstomaintainsoiltemperature  Ithelpstomaintainsaltbalance  Itreducessalinityandalkalinity  Itinfluencesweedgrowth  Itinfluencesatmosphericweather  Ithelpsthebeneficialmicrobes  Itinfluencesthepestanddiseases  Itsupportshumanandanimallife  Ithelpsforlandpreparationlikeploughing,puddling,etc.,  Ithelpstoincreasetheefficiencyofculturaloperationslikeweeding, fertilizerapplicationetc.,byprovidingoptimum condition. Q.2.Define crop waterrequirement.EnlistFactorsinfluencing crop waterrequirement. CropwaterRequirement Cropwaterrequirementisthewaterrequiredbythe plantsforitssurvival,growth,developmentandtoproduceeconomic
parts.Thisrequirementisappliedeithernaturallybyprecipitationor artificiallybyirrigation.  Factors 1)Cropfactors  Variety  Growthstages  Duration  Plantpopulation  Cropgrowingseason 2)Soilfactors  Structure  Texture  Depth  Topography  Soilchemicalcomposition 3)Climaticfactors  Temperature  Sunshinehours  Relativehumidity  Windvelocity  e)Rainfall 4)Agronomicmanagementfactors  Irrigationmethodsused  Frequencyofirrigationanditsefficiency  Tillageandotherculturaloperationslikeweeding,mulchingetc/ intercropping. Q.3.Define Irrigation requirement.State the factors on which IR depends. Irrigationrequirement The field irrigation requirement of crops refers to water
requirementofcropsexclusiveofeffectiverainfallandcontributionfrom soilprofileanditmaybegivenasfollows IR-WR–(ER+S) IR-Irrigationrequirement WR-Waterrequirement ER-Effectiverainfall S-Soilmoisturecontribution Irrigationrequirementdependsuponthe a)Irrigationneedofindividualcropbasedonareaofcrop b)Lossesinthefarm waterdistributionsystem etc. Allthequantitiesareusuallyexpressedintermsofwaterdepthperunit oflandarea(ha/cm)orunitofdepth(cm). Q.4.DefineCriticalstagesforirrigation.Statecriticalstagesfordifferent crops. Criticalstagesforirrigation: The stage atwhich the waterstress causes severe yield reductionisalsoknownascriticalstageofwaterrequirement.Itisalso knownasmoisturesensitiveperiod.Moisturestressduetorestricted supplyofwaterduringthemoisturesensitiveperiodorcriticalstagewill irrevocablyreducetheyield. Sensitivestageofdifferentcropscerealsandmillets Crop-Criticalstages/Sensitivestages Rice-Panicleinitiationcriticalstaps.headingandflowering Sorghum -Floweringandgrainformation Maize-Justpriortotasselingandgrainfilling Ragi-Primordialinitiationandflowering Wheat-Crownrootinitiation,tilleringandbooting