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1、第六章各类农产品贮藏技术第一节粮食贮藏（储藏）第二节果品贮藏第三节蔬菜贮藏Section1GrainStorageGrainharvesting,threshingandcleaningDryingmethodsThebiodeteriorationofgrainandtheriskofmycotoxinsStorage1、Grainharvesting,threshingandcleaning(i)HarvestingmethodsSometimes,itisdesirabletohastenthetimeofcropharvesting.Afteragrai
2、ncropreachesphysiologicalmaturity,anydelayinharvestingmaycausedeteriorationinqualityandyieldreduction.Anumberofdirectandmethodsmaybeadoptedbycropproducerstohastenthetimeofcropharvesting.Physiologicalmaturitydefinedasmaximumkerneldryweight,moisturepercentagerangesfromabout20to40%（25~3
3、0%）.determinesthereadinessofthecropforharvest.Thisstageofcropdevelopmentisreachedpriortothecropbeingreadyforcombiningasthekernelisrelativelysoft(easilydentedwithfingernail)andkernelmoisturepercentageisrelativelyhigh.Onceaplanthasattainedphysiologicalmaturity,itcannotaccumulateanymore
4、drymatter.HarvestingHarvestingmethodsdifferaccordingtothepartoftheplanttobeused.Asregardsforagecrops,thewholeplantiscut,butforundergroundcrops(eg,groundnuts,rootsandtubers),thecropisliftedwhilethesoilstickingtoitisremoved.Withcereals,thecropisfirstcuteitherasawholeorpartially(ears),a
5、ndthenthreshedandcleanedtoseparatethegrainfromtheearsandstraw.Inthelattercasetwomainalternativesexist:separateharvestingandthreshing,orcombinedharvestingandthreshing.HarvestingHarvestingmethodsManualharvestingMechanizedharvestingDIRECTMETHODSDefoliationandDesiccationLeavingitinthefie
6、ldlongerpredisposesittoweathering.Sometimes,inclementweatherthreatensthequalityoftheharvest,therebycompellingtheproducertomakeadjustmentsintheharvestingschedule.Suchadjustmentsinclude“inducing”earlyharvestmaturitybyapplyingadefoliantordesiccant.HarvestingAdefoliantcausesleaf-drop,whi
7、leadesiccantcausestheplanttodryoutinthefieldanddie.Incottonproduction,greenleavestendtostainthefibers.Defoliationofcottonpriortomechanizedharvestingreducesnotonlytheamountofundesirableplantdebrisintheharvestedfiberbutalsothechanceoftaintingitwithplantpigments.HarvestingINDIRECTMETHOD
8、SGenerally,c
