(1.InstituteofAgriculturalResourcesandRegionalPlanning,ChineseAcademyofAgriculturalSciences/
KeyLaboratoryofAgri-informatics,MinistryofAgriculture,Beijing100081,China;
2.EnvironmentandProductionTechnologyDivision,InternationalFoodPolicyResearchInstitute,
2033KStreet,NW,Washington,DC20006,USA)
Abstract:RiceisoneofthemostimportantstaplesinChina.Rice'sspatial-temporaldistributions,whicharevitaltoagricultural,environmentalandfoodsecurityresearch,areaffectedbynaturalconditionsaswellassocial-economicdevelopments.Inrecentyears,mostofagriculturallandusechangestudiesarefocusedoncultivatedlandchangeanditsimpact,whilefewarefocusedonarablecropareachangebecausecropsownareaestimatesarebasedonstatisticsbyadministrativeunits,andsuchdatalackaccurateinformationonspatialandtemporalvariations.Otherestimatesarebasedonremotesensing,suchdatalimitedbyspatialresolutionwhichisdifficulttocapturethefinerinformationofcrops.Thus,multi-sourcedataintegrationhasbecomeaneffectivewaytodeterminespatialdistributionsofcrops.SpatialProductionAllocationModel(SPAM)isamulti-sourcedataintegrationmodelthatintegratedarablelanddistribution,administrativeunitstatisticsofcropdata,agriculturalirrigationdata,
5期刘珍环等：近30年中国水稻种植区域与产量时空变化分析693
andcropsuitabledata.Itappliedacross-entropymethodtoallocatethestatisticsdataofcrop
areaandproductiondowntosuchafinespatiallocation,suchasapixel.ThisresearchusestheSPAM-Chinamodeltogetaseriesofspatialdistributionsofriceareaandproductionwitha10-kmpixelatnationalscale,basedonlong-termcounty-andprovince-levelagriculturalstatisticssincetheearly1980s,andthen,analyzesthepatternofspatialandtemporalchanges.TheresultsshowthattherearesignificantchangesinriceinChinaduring1980-2010.Overall,morethan50%ofriceareadecreased,whilenearly70%ofriceproductionincreasedinthechangeregionduring1980-2010.Spatially,mostoftheincreasedareaandproductionwereinNortheastChina,especially,inJilinandHeilongjiang,mostofthedecreasedareaandproductionwerelocatedinsoutheasternChina,especially,inrapidlyurbanizedprovincesofGuangdong,FujianandZhejiang.Thus,thecentroidofriceareawasmovedtonortheastapproximately230kmsince1980,andriceproductionaround320km,whichmeansriceproductionmovesnortheastwardfasterthanriceareabecauseofthesignificantriceyieldincreaseinNortheastChina.Theresultsalsoshowthatriceareachangehasadecisiveimpactonriceproductionchange.Approximately54.5%oftheincreaseinriceproductionisduetotheexpansionofsownarea,whilearound83.2%ofthedecreaseinriceproductionisduetoshrinkageofricearea.Thisimpliesthatriceproductionincreasedmaybeduetoareaexpansionandothernon-areafactors,butreducedriceproductioncouldlargelybeattributedtoriceareadecrease.
Keywords:ricedistribution;spatialproductionallocationmodel;spatial-temporalchanges;China