ACCURACY OF FIELD SAMPLING FOR SOIL TESTS
[摘要] ThreewidelyseparatedAlbertafieldsweresampledintensivelyinagridpattern,toestimatetheeffectofnumberanddepthofcoresandoffieldsizeontheaccuracyofcompositesamplesusedinsoiltestanalyses.Estimateswereobtainedbybothstatisticalandcomputersimulationtechniquesandbothgavesimilarresults.Accuracyofcompositesincreasedwiththenumberofcores,butevenwithasmanyas30coresperfieldtherewasstillconsiderableinaccuracyinvaluesforNandP.Inthemostvariablefield,acompositeof20coresforthe0-to15-cmdepthpredictedthetruefieldmeanwithin± 10%forN,PandKonly47,56,and82timesoutof100,respectively.Correspondingvaluesfortheleastvariablefieldwere77,70,and98.ConductivityandpHweremoreaccuratelyestimatedwiththesamenumberofcores.Samplestakenatthe15-to30-cmand30-to61-cmdepthsshowedgreatercoefficientsofvariabilityinNandPthandidsamplesfromthe0-to15-cmdepth.However,samplescomposedof...
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[效力级别] [学科分类] 农业科学（综合）
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