[Differences of soil nutrients among different vegetation types and their spatial prediction in a small typical karst catchment.].

Vegetation types restrict soil structure and heterogeneous processes of elements, which result in difference in spatial distribution of soil nutrients. In this study, the differences in contents of soil nutrients, TN, TP, TK, and soil organic matter (SOM) among different vegetation types were analyzed, and the accuracy of ordinary kriging, regression model and regression model based on vegetation type in predicting soil nutrients was compared. The results showed that, TN, TK and SOM were significantly (P<0.

[Spatial heterogeneity of surface soil mineral components in a small catchment in Karst peak-cluster depression area, South China].

A total of 163 soil samples (0-20 cm layer) were collected from the grid sampling plots (80 m x 80 m) in Huanjiang Observation and Research Station of Karst Ecosystem in a small catchment in Karst cluster-peak depression area, South China. By using classical statistics and geostatistics, the spatial heterogeneity of mineral components (SiO2, Fe2O3, CaO, MgO, Al2O3, MnO, and TiO2) in the soils were studied. The contents of the seven soil mineral components in the study area differed greatly, being in the order of SiO2 > Al2O3 > CaO > MgO > Fe2O3 > TiO2 > MnO, and the variance coefficients also varied obviously, in the order of CaO > MgO > Fe2O3 > TiO2 > SiO2 > Al2O3 > MnO.