title: Geostatistical interpolation of available copper in orchard soil as influenced by planting duration.
abstract: Mapping the spatial distribution of available copper (A-Cu) in orchard soils is important in agriculture and environmental management. However, data on the distribution of A-Cu in orchard soils is usually highly variable and severely skewed due to the continuous input of fungicides. In this study, ordinary kriging combined with planting duration (OK_PD) is proposed as a method for improving the interpolation of soil A-Cu. Four normal distribution transformation methods, namely, the Box-Cox, Johnson, rank order, and normal score methods, were utilized prior to interpolation. A total of 317 soil samples were collected in the orchards of the Northeast Jiaodong Peninsula. Moreover, 1472 orchards were investigated to obtain a map of planting duration using Voronoi tessellations. The soil A-Cu content ranged from 0.09 to 106.05 with a mean of 18.10 mg kg-1, reflecting the high availability of Cu in the soils. Soil A-Cu concentrations exhibited a moderate spatial dependency and increased significantly with increasing planting duration. All the normal transformation methods successfully decreased the skewness and kurtosis of the soil A-Cu and the associated residuals, and also computed more robust variograms. OK_PD could generate better spatial prediction accuracy than ordinary kriging (OK) for all transformation methods tested, and it also provided a more detailed map of soil A-Cu. Normal score transformation produced satisfactory accuracy and showed an advantage in ameliorating smoothing effect derived from the interpolation methods. Thus, normal score transformation prior to kriging combined with planting duration (NSOK_PD) is recommended for the interpolation of soil A-Cu in this area.
authors: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors: Chuancheng
authors: C
authors: Fu
authors: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors: Haibo
authors: H
authors: Zhang
authors: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors: Chen
authors: C
authors: Tu
authors: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors: Lianzhen
authors: L
authors: Li
authors: Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China. ymluo@yic.ac.cn.|University of Chinese Academy of Sciences, Beijing, 100049, China. ymluo@yic.ac.cn.
authors: Yongming
authors: Y
authors: Luo
mesh_terms: D000383:Agriculture / Q000379:methods*; D002681:China; D003300:Copper / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005659:Fungicides, Industrial / Q000032:analysis*; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D062206:Spatial Analysis
chemical_list: D005659:Fungicides, Industrial; D012987:Soil; D012989:Soil Pollutants; D003300:Copper
keywords: Available Cu; Geostatistical interpolation; Jiaodong Peninsula; Normalization methods; Orchard soil; Planting duration