Study On Spatial Variability And Regionalized Management Of Soil Nutrients

gb．D．Student:Huang Shaowen AdVISOO:Jlll】ylll Scientific management of soil nutrient and rational use of fertilizers re strategic issuesaffecting su石talnablllty of Chinese agriculture．Howeve．soil nutrient status,especially spatialvarlablllty of nutrients In a ield or In a region,and corresponding management appro砒heshave not been studied systematically and comprehensively In China．Application ofInformation technologX such as GIS and GPS,and geo－statistics in soil fertility variabilitystudy is In its Initial stage．Balanced feFtlllzer application t farms'level In China has not beenreallied．In this research,Yutlan county of Hebel and Ling county of shandong were selectedas two experimental regions(Yutlan expenmental region Includes two research scales,Hongqlao township and the whole county)．Soil nutrient spatial varlablllty characteristics werestudied using modern nd advanced techology nd approaches．This will give scientific basesto develope balance fertilizer application teehlques suitable to Chinese status of small scalefarming management．The main results obtained are summarized s follows: l．Preliminary evaluation ofsoil nutrlentstatus pvallable nutrient contents of surface soil samples fromWtlan and Ling experimentalregions were determined using the systematic aPproaches for soil nutrient evaluation．Effects ofthe different crop types on soil avalbole nutrient contents In Yutlan experimental region weredlscmsed,nd soil nutrient status for grain crop regions In伽在n nd Ling experimentalregions was evaluated using tr刎ltlonal烟tlstlcs．The results Indicated that the different croptypes had a significant e月毛以on sollguailable nutrient co口广ents．Soilgyailable N,P K,Mn ndFe contents for apple tree,grapevine,and vegetable regions were obviously higher than that ofgrain crop region,especially民 Mn and Fe．Thus,d计比rent crop type and history offertlllzermanagement are important作比tors In devdopment ofa Inye scale reglonallzed son nutrientmanagement program． gain soiln以rlent limiting factors for gr山n crop region In different experimental regionsvaried remarkably Soils InY亡tian experimental region were widely deficient InN,只 K,Mn,and Zn while those In Ling experimental region were N,K,and Zn．The distribution of soilavallab！e nutrient contents In the two eXpenmental regions of Yuian and Ling county had ageneral geographical tendencX especially In Wtlan e邓enmental region．In Wtlanexpenmental region,soil OM,and available N,只K,Mn,and Zn testing values generally fell In2 to 3 neighboring nutrient evaluation classes．While In Ling expenmental regiofl soil OM,andavailableN,只 and Zntestingvalues mainly fell Inl orZ neighbonngn［ltTlellt evaluation 96 classes．Therefore,It will be possible to develop a reglonllzed soil nutTlent management progr山nbrN,巳 K,Mn,andzn InWtlan experimental region andbrN,只 andZn h Ling experimental region． 2．Spatial variability ofsoil nutrients Spatial varlablllty structure ofsoll available nutrient contents fortwo experimental regions ofWtlan nd ying county was analyzed and discussed using semi－variance analysis or geo－ statistical methods．The results Indicated that semi－variance structLlres for spatial varlablllty of available soilN,P K,Mn,and Zn existed In two research scales from Yutlan experimental region．The limit distances of spatial corelation were relatively large,Zg．3～105．l咖阶the grain crop region In entire伽tlan county and 4．3—5．7h for Hongqlao township region．It revealed thatthe spatial correlation In available nutrlentcontentsdeveloped In relative large－ b！ock scales,and the basic tendency wil useful for development of regional！zed nutrient manage...