Spatial
JournalofMountainScienceVol1No1(2004):89—95
;l,?.h./,……;？,…,:…一1
;ArticleID:1672-6316(2004)O1-0089.O7
;SpatialDisparityofSlopeFarmlandandFood
;WANGLiming回
;InstituteofGeographicalSciencesandNaturalResourcesResearch,CAS,BeO‟ing100101
;E—mail:Wanglm@igsnrr.accn|wanglm2ooo@yahoocom ;FENGRenguo
;BureauofScienceandTechnologyforResourcesandEnvironment,CAS,BeO‟ing100864,China
;YANGYanfeng
;DepartmentofGeography,TheUniversityofHongKong,China ;GUANQingfeng
;InstituteofGeographicalSciencesandNaturalResourcesResearch,cBeijing100101,China
;Abstract:Asanimportantmeasureofeco.
;environmentalconstruction,theprocessof
;de-farminginslopefarmlandisbeingundertaken ;graduallyintl1ewholeChina.Meanwhile.theproblem ;ofreducinginfoodyieldinde—farmingareascannot
;beneglectedanymore.Itisespeciallythecasein ;areaswitl1concentratedslopefarmlandand
;inconvenienttransportation.Intl1ispaper.weanalyze ;tl1ecausesofhiddentroublesinfoodsecurity,andthe ;spatialrelationshipbetweenfarmlandandslope ;farmlandintl1ereservoirareaofThreeGorges.and ;unveiltl1espatialdisparityofcontradictionsbetween ;foodsupplyanddemand.Finally,combiningthe ;accessibilityofareas,threedifferentspatialtypesof ;foodsecurity,foodsecurityarea,foodalertarea,and ;foodcrisisarea,aredivided.
;Keywords:Slopefarmland;de-farming;food
;security;spatialdisparity
;ThereservoirareaofThFeeGorgesinthispaperrefersto20 ;countylevelregion:Yichang,Xingshan,Zigui,Badong,Wushan, ;Wuxi,Feng~ie,Kaixian,Yunyang,Wanzhou,Zhongxian,Shizhu, ;Wulong,Fengdu,Fuling,Changshou,Yubei,Banan,Chongqing ;downtown,andJiang~in.
;Received:30June2003
;Accepted:10October2003
;In1998,atremendousflooddisasteroccurred
;inYangtsedrainagearea,whichwasdirectly ;causedbytheclimateabnormity,whilesoilerosion ;intheuppercoursealsotookanimportantrolein ;conductingtheflooddisaster(LiWenhua1999,Shi ;Deming1999).Thehugedamagecausedbythe ;disastermadethecentralgovernmenttopaygreat ;attentiontotheeco-environmentalconstructionin ;themiddleanduppercoursesofYangtseRiver.The ;de—farmingprojectinslopefarmlandisundertaken ;graduallyinthewholecountryasanimportant ;measureofeco—environmentalconstruction
;(PeopleDaily,Sep.26,2000).Experimentsof ;returningslopefarmlandtowoodlandand ;grasslandhasbeenconductedin20provinciallevel ;areasalloverthecountryin2OO1(PeopleDaily. ;Mar.17,2OO1).Itisestimatedthatfill2010.the ;de—-farmingprojectwillcontrolsoil..erosionareasof ;o.34billionmu(15mu=1hectare)andreducethe ;amountofsedimentbyo.21billiontonsflowing ;intoYellowRiverandYangtseRivereveryyear ;(PeopleDaily,Feb.16,2OO1).
;TakingthereservoirareaofThreeGorges,one ;oftheexperimentalunits,asthecasestudy,and ;usingthetechniqueofGIS,thispaperexploresthe ;spatialdisparityofslopefarmlandandfood ;
;WANGLingming,FENGRenguo,YANGYanfeng,andGUANQingfeng ;securitycausedbyde—farmingaction.Finally,three ;differentspatialtypesoffoodsecurityaredivided. ;1De-farminginSlopeFarmlandinthe
;ReservoirAreaoftheThreeGorges
;andHiddentroublesinFoodSecurity
;BasedontheFA0(FoodandAgricultural
;Organization)definition,foodsecurityisthe ;securityofnecessaryfoodthatisaffordableto ;anybodyinanytime.Foodsecurity.whichisan ;integratedsecuritysystem,isnotonlyaconceptof ;f0odproduction,butalsoineludescirculation. ;reservation,importandexportregulationandso ;on.The”TenthFiveYearPlan”ofChinafirstly
;introducedtheconceptionof‟Foodsecurity‟.and
;announcedtoestablishafoodsecuritysystemthat ;issuitabletoChinesesituationandsocialism ;marketeconomytokeepthebalanceoffood
;demandandsupply(ZhuRongji,PeopleDaily,Oct. ;20,2000).
;Inrecentyears,theconcentrationsonfood ;securitymainlyfocusedonthenationallevelrather ;thanthesubnationallocalleve1.Infact.inthelocal ;leveltherearestilllotsofproblemsconcerning ;thfoodsecurity.FA0‟sdefinitionoffoodsecurity
;comprisesseveralimportantkeywords:‟anybody‟,
;„anytime‟and‟affordable‟.‟Anybody‟referstothe
;populationofthewholecountry.oralocaldistrict; ;„anytime‟canbeanabundantyear,oradisaster
;year;‟Affordable‟meansthepeopleshouldhave
;enoughmoney.Therearespatialdisparitiesin ;Chinainallthesethreeaspects.So,theproblemsof ;f0odsecuritymayoccurnotonlyinnationallevel ;butalsolocalleve1.
;Basedonthesecriteriaoffoodsecurity,the ;hiddentroublesinfoodsecurityinthereservoir ;areaofThreeGorgesincludefollowingthree ;aspects:
;(1)Thefoodsecuritytofarmers(thosewhodid ;notreturnanyoftheirfarmlandtogreen—land)in
;thereservoirareaandtheuncertaintyoffood ;supplytode—farmers(thosewholostsomeortotal ;oftheirfarmlandinde.farmingaction).Unlikethe ;condifionsofwesterncountries,thefood ;productioninthereservoirareaisbasedonlotsof ;smal1.sizedseparatedfarms.Onlyafterthe ;producershavefulfilledtheirOWl2needs,canthey ;arrangethemerchandiseproduction.Itisakindof ;self-protectionandfamily..basedfood..security ;system.I.hisforillsthespecialstructureoffood ;productionandexchangeinthereservoirarea. ;Althoughatpresentthekindsoffoodthefarmers ;consumearenotentirelywhattlleyproduce,and ;theyexchangesomekindsoffoodinthemarket, ;thefoodmerchandiserateisstillquitelow.The ;family-basedfood—securitysystemmakessurethe
;steadyfoodsupplytofarmers,thusisthemost ;importantfactortostabilizetllefood—securityin
;thereservoirareathroughal1thoseyearswithout ;enoughfarmlands.Eveninadisasteryear,aslong ;asthereisasmal1harvest.itcanstillmaintainthe ;reproductionoflaborforcetosomeextent.
;However,thefamily—basedfood—securitysystem
;encumbersthedevelopmentoflocalfoodmarketat ;thesametime.Afterde-farming,thesteady ;situationmaybebrokenup:thefarmerswhostill ;havetheir1andcanmaintainahighstandardof ;f0odsecurity.whilethefm;rnerswholosttheir ;landshavea1owerstandardoffoodsecurity.0nee ;thefoodsupplygivesacrisissignal,thefarmers ;whostillhavelandswillstrengthentheir ;self-supplyfoodproduction,theirhouseholdfood ;storagewillincrease.whilethefarmerswholost ;theirlandscanonlydependontheimportedfood. ;andmayhaveariskoffoodshortage.After ;de—farming,eveniftheaveragesituationoffood ;supplyinthereservoirareaisfairlywel1.itmaynot ;bethesamecaseto‟anybody‟.therearestil1some
;uncertaintiesinfoodsupplywitllthefarmerswho ;losetheirlands.
;(2)ThereservoirareaofThreeGorgesisa ;placewherenaturaldisastersoccurfrequently,and ;theagriculturalinfrastructuressuchasirrigation ;worksarenotdeveloped,sotheabilitytoprevent ;thedisastersislimited.Forexample.intheearly ;summertheremaybesomedroughtdisastersthat ;willcauseagreatdecreaseinfoodproduction.so ;theannualfoodproductionofdifferentyearsmay ;fluctuategreatly.Meanwhile,mostofthe ;farmlandsinthereservoirareaarelocatedonthe ;slopes,whichcausetheinconvenienceoffood ;transportation.Sothecostoffoodtransportingis ;high,andthetimeoftransportationwillnotbe ;guaranteed.Ifthereisalarge—scaledisaster.the
;trafficconditionswouldbeagreat1imit,andthe ;f0odsupplywouldnotmeetthedemandat
;„anytime‟.
;
;
;(3)ThepoorpeopleconcentrateintheThree ;Gorgesarea,andtheeconomicfoundationisweak. ;Theregulationofde—farminghasaclear
;prescriptionontheproportionofecologicalwoods ;andeconomicwoods.Thequantityofecosystem ;woodsshouldreachabout80percentafter ;de—farming.Therefore,de—farmedpeasantsare
;restrictedinsearchingforenoughproduction ;resources.Moreover,thepolicyofsubsidyisiust ;forthepresentstage,butthefoodconsumptionis ;continuous.Guaranteeingthefoodsupplybythe ;governmentnodoubtlesslyisacontinuous ;pressuretopublicfinance.Inordertomakesure ;allthepeasantsinthede—farmingareascan
;continuously‟afford‟thefoodtheyneed,somehard
;worksstillneedtobedone,includingthe ;developmentoflocaleconomyandthefinancial ;supportfromthegovernment.
;Besidesthethreespecificregionalreasons ;above,consideringthemacroscopicbackground, ;therearestillseriousproblemsoffoodsecurityin ;China.Thesituationofabundantfoodsupplymay ;stillbeconvertedthuswillinfluencethe ;food—securityintheThreeGorgesarea.In1997, ;f00dpercapitainChinawasmorethan400kgand ;f00dstorageaccountsfor30percentoffood ;consumption,whichwashigherthanthegenerally ;acceptedinternationalstandardof18percentof ;foodsecurityertline.Thepercapitafoodand ;storagereachedthemaximuminthehistory.But ;now,theabilityoffoodproductioninChinais ;unsteady.andisvulnerabletotheserioustrialof ;naturedisasters.Iffood—plantingareaisreduced
;continuously,andthegapbetweenfoodproduction ;andsupplyexistsforyears,foodsecuritywouldbe ;spoiled.Thede—farmingpolicynamedproviding
;grainasaformofreliefcameintobeinginthe ;specialbackgroundthattotalquantityoffood ;supplyexceededdemand,whichmightbea ;temporarysituation.Ifthesituationisconverted, ;thepolicyofrelivinggraininsteadofmoneywould ;behardtofulfil1.
;Theproblemsoffoodsecurityhavestrong ;relationshipwiththefulfillmentofthede—farming
;Dr03ect.Iffoodsupplyislowerthanfooddemand ;inthede—farmingareas,thepressureofreclaiming ;thede—farmedslopefarmlandswillexist.Therefore. ;approachingtheproblemsoffoodsecurityis ;importantnotonlyforthelivingstandardoflocal ;people,butalsofortheeffectofde—farmingpr03ect.
;JotmlalofMountainScienceVol1No1(2004)
;2TheSpatialDisparitiesofFoodSupply ;andDemandRelationshipsafter
;De—farmingintheReservoirArea
;So—called‟spatialdisparitiesoffoodsupplyand
;demandrelationships‟referstothesurplusoffcIod
;productiontofooddemandinsomeareas.and也e
;shortageofproductioninotherareas.Befclre ;de—farming,foodsupplyanddemandrelationships ;intheresecvoirareaalreadytookcertainspafial ;disparities,butthetextualpointishowtosettlethe ;newdisparitiesbroughtoutbvde—farming.The
;followingaspectsarethemaincausesofthespatial ;disparities:(1)Thespatialdisparitiesofde—farmed
;slopefarmlandscausespatialdisparitiesoffood ;demand.Thoseareaswithconcentrated ;de—farmingslopefarmlandswillfacehigherfood ;demandpressure,whiletheareaswithscattered ;de—farmingslopefarmlandswillhavelower ;pressure;(2)Slopefarmlandswhichhavenot ;de—farmedhavespatialdifferences,thuscause ;spatialdisparityoffoodsupply.Thoseareaswith ;c0ncentratedfarmlandsthatneednottobe ;de—farmedhavestrongcapacityoffoodsupply,and ;thecapacitytoalleviatethefooddemandpressure ;arealsostrong;(3)Spatialdisparitiesof ;transportationaccessibilityinfluencefood ;transportationandtimeliness.
;Inordertomeasurescientificallythespatial ;disparityoftheabovethreeaspects,wemadeuse ;ofthe‟integratedhuman—naturedataplatform‟
;constitutedbythelandusedatainterpretedfrom ;TMremotesensingimagesfortheChinese ;resourcesenvironmentdatabases.theDigital ;ElevationModel(DEM)data.andothersocialand ;economicdata.
;Belowarerespectivemeasurementsofspatial ;disparitiesofslopefarmlands,farmlandsand ;transportationaccessibilitybasedontheGIS. ;2.1Measurementofspatialdisparitiesof ;slopefarmlands
;Firstly,tocreatelandgradientdataofthe ;reservoirareausingDEMdatabase,andquery ;farmlanddatainlandusemap.thengetthedataof ;slopetarmlandover25degreebycrossquerynng.
;Sincetheseslopefarmlanddataonlydescribethe ;distributionofsingleparcels,itisnotenoughto ;explainthedegreeofspatialconcentration,a ;91
;
;WANGLingming,FENGRenguo,YANGYanfeng,andGUANQingfeng ;coefficientindexisdesigned,whichisnamedslope ;farmlanddistributioncoefficient.Itindicatesthe ;proportionofslopefarmlandinlandperunit.The ;formulais:
;“
;?(xq女xh女)k:l
;k=1,2,…,n
;×100(1)
;Informula(1),UiiSthedistributionindexof ;slopefarmland.SkiStheareaoflandunitkinthe ;neighborhoodoflandunit,qkistheproductivity ;indexofk.andhkiStheidentificationparameterof ;slopefarmland(1forslopefarmland,andofor ;others).
;ThevalueofuirangesfromotolOO,Whenui ;=o.itindicatesthereisnoslopefarmlandsinthe ;neighborhoodoff;whenui=lOO,itmeansall ;farmlandsareslopefarmlandsintheneighborhood ;off.
;qkrepresentsfarmlandproductivityinfluenced ;bydiversitiesinsoil,height,slope,hydrothermal ;condition,etc.Usually,farmlandswiththesame ;areacannotsubstituteequallybecauseof ;differencesinfarmlandquality.SoweuseSkqkto ;transforillareaoffarmlandintostandardizedarea ;offarmlandwhichcanbesubstitutedequally,and ;wecallitstandardarea.
;2.2Measurementofspatialdisparities ;Non-?of??de-?farmingfarmlands
;Non?—de-?farmingfarmlandsaresuchfarmlands ;thgradientlessthan25..Theformulaforthe ;distributionindexofnon-?de-?farmingfarmlandis: ;?(xq×)
;v=』皇———————一×1oo
;l”
;?
;uisthedistributionindexofno.de—farmed
;farmland,hrkiStheidentificationparameterof
;farmland(1fornon./de.farmedfarmland,ando ;forothers).
;Thevalueofu{alsorangesfromoto100, ;Whenvf=o,itindicatesthatthereisnofarmland ;intheneighborhoodofwhenvi=100,itmeans ;tllatalllandarefarmlandsintheneiborhoodof ;f.
;2.3Measurementofspatialdisparitiesof ;transportationaccessibilityforfood ;security
;Factorsinfluencingtransportationaccessibility ;f0rfoodsecurityincludethedistributionof ;transportationlinesanddirentlandformsinthe ;reservoirareaofThreeGorges.Theindexof ;transportationaccessibilityiscalculatedbythe ;followingformula:
;(3)
;istheindexoftransportationaccessibilityof ;landunit:risthenumberofthefactors ;influencingtransportationaccessibility;wjisthe ;weightofpi,andpiisthefuzzyindexfunctionof ;evaluatingfactor『.
;fiscalculatedbyafuzzymul廿.factor
;comprehensiveevaluationmodelbasedonmap ;algebraoperation.Theformulaisasfollow: ;g(x)=
;唧…？一易
;1when以一易<<以+易
;唧
;『-(…一易
;init,=2,,:垒!(4)
;41n2din2
;a,b,c,darefourparametersthatidentifythe ;shapeoftheindexfunction.Whenisbetween. ;6)and(a+6),theindexreachestoitsmaximum,1. ;Whenisnomorethan(Q一6),ornolessthan(Q+
;6),theindexiscalculatedbytheabovefunction. ;Whenxisequaltocord.theindexiSO.5. ;Thevalueofrangesfromoto100,when=
;100,itmeansthesituationoftransportationisthe ;bestinthearea,When=o,itindieatesthe ;situationoftransportationistheworstinthearea. ;?
;0
;0
;×
;?
;=
;
;3Simulationofthe
;foodsecurity
;indexofde-farming
;Inordertoquantitatetheleveloffoodsecurity. ;theindexoffoodsecurityiSinduced.Thebigger ;thevalueofthisindexiS.thebettertheleveloffood ;security.andviceversa.ThevalueoftheindexiS ;determinedbytheinterplayamongUi,Ui,.Uiand ;varyinthesamedirectionwiththefoodsecurity ;index,whichmeansthebiggerthevaluesofUand ;.thehighertheleveloffoodsecurity.Onthe ;contrary,Uivariesintheoppositedirectionwith ;thefoodsecurityindex.whichmeansthebiggerthe ;valueofUi,thelowertheindexoffoodsecurity.For ;betterunderstanding,UiisreplacedbyU‟i,whichis
;calculatedasfollow:
;“.
;,=
;1-ui
;(u))MAX(u×?..c5
;MAX(u)isthemaximumofUiinthewhole
;reservoirareaofThreeGorges.
;SupposeAistheindexoffoodsecurity,then: ;Al=W114+WV+(6)
;AiiStheindexoffoodsecurityforlandunitf.W ;?u,?raretheweightsforu,Ui,,whichare
;endowedwiththevaluesofO.66,O.26,O.08.The ;valueofAirangesfromOto1OO,thebiggerthe ;value.thehighertheleveloffoodsecurity. ;Therelocationoffarmlandsafterde.farming ;wouldoftenoccurwithinthelevelofadministrative ;village.Iffarmlandsareadjustedwithintheunits ;oftownorcounty,acceptabledistancefor ;cultivationwillbeexceeded.andfarmershaveto ;changetheirlivingplacesandbecome
;environmentalemigrants.So,farmlandsrelocation ;acrossadministrativevillagesiSquitecomplicated. ;ItiScalculatedthattheaverageradiusof ;administrativevillagesinthereservoirareaiS1I22
;km.Concerningtheirregularityofthespatialshape, ;theradiusofthemodelingneighborhoodiSdefined ;as1.5km.
;Thefoodsecurityindexforde.farmingcanbe ;calculatedthroughformula(5),theresultsrange ;from10to1OO.Taking30aStheinterva1.three ;differentspatialty