title: Selection of optimal auxiliary soil nutrient variables for Cokriging interpolation.
abstract: In order to explore the selection of the best auxiliary variables (BAVs) when using the Cokriging method for soil attribute interpolation, this paper investigated the selection of BAVs from terrain parameters, soil trace elements, and soil nutrient attributes when applying Cokriging interpolation to soil nutrients (organic matter, total N, available P, and available K). In total, 670 soil samples were collected in Fuyang, and the nutrient and trace element attributes of the soil samples were determined. Based on the spatial autocorrelation of soil attributes, the Digital Elevation Model (DEM) data for Fuyang was combined to explore the coordinate relationship among terrain parameters, trace elements, and soil nutrient attributes. Variables with a high correlation to soil nutrient attributes were selected as BAVs for Cokriging interpolation of soil nutrients, and variables with poor correlation were selected as poor auxiliary variables (PAVs). The results of Cokriging interpolations using BAVs and PAVs were then compared. The results indicated that Cokriging interpolation with BAVs yielded more accurate results than Cokriging interpolation with PAVs (the mean absolute error of BAV interpolation results for organic matter, total N, available P, and available K were 0.020, 0.002, 7.616, and 12.4702, respectively, and the mean absolute error of PAV interpolation results were 0.052, 0.037, 15.619, and 0.037, respectively). The results indicated that Cokriging interpolation with BAVs can significantly improve the accuracy of Cokriging interpolation for soil nutrient attributes. This study provides meaningful guidance and reference for the selection of auxiliary parameters for the application of Cokriging interpolation to soil nutrient attributes.
authors.affiliation: Institute of Agricultural Remote Sensing and Information Technique, Zhejiang University, Hangzhou, Zhejiang, China; and Ministry of Education Key Laboratory of Environmental Remediation, Ecological and Health, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Genxin
authors.initials: G
authors.lastname: Song
authors.affiliation: Institute of Agricultural Remote Sensing and Information Technique, Zhejiang University, Hangzhou, Zhejiang, China; and Ministry of Education Key Laboratory of Environmental Remediation, Ecological and Health, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute of Agricultural Remote Sensing and Information Technique, Zhejiang University, Hangzhou, Zhejiang, China; and Ministry of Education Key Laboratory of Environmental Remediation, Ecological and Health, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
mesh_terms: D004784:Environmental Monitoring; D012987:Soil
chemical_list: D012987:Soil