Spatial variation of soil minerals in the gorge Karst region, southwest China

Abstract

Spatial variation analysis of soil minerals is useful for ecological restoration and vegetation reconstruction. In this study, the spatial variation of soil minerals over a typical sloping farmland was investigated in a gorge karst region in southwestern China. The total study area (300 m 伊 200 m) was divided into grids of 20 m伊 20 m and included 212 sample points. Soil minerals ( SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, MgO, and MnO) , in surface soil were measured. The spatial patterns of soil minerals were analyzed with classical statistics and geostatistics methods. The differences of the content of the six minerals were large, but the variation coefficients were small. The sum of SiO 2 and Al 2 O 3 accounted for 85.99% of the sum of the six mineral components. SiO 2 , Al 2 O 3 , MgO, and MnO, while Fe 2 O 3 and CaO were normally distributed after square and reciprocal transformed, respectively. SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO, MgO, and MnO were best fitted by an Exponential model, with high coefficients ( R 2 ) or low residual sum of squares ( RSS) indicating that the fitted models could reflect the spatial variation of soil minerals. The nugget ( C 0 ) was low (3.0%-43.6%) , indicating that the soil minerals were strongly autocorrelated over the study region, and that their spatial patterns were influenced by structural factors. These spatial