[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<0.05) correlated to vegetation type, and TP had no significant correlation with vegetation type (P=0.390). TN and SOM had significant difference between shrubbery and arable land. TK had significant difference between arbor and scrub-grassland, shrubbery and arable land, and scrub-grassland and arable land, respectively. In a non-continuous typical small karst catchment, because of high spatial heterogeneity of terrain, the accuracy of multivariate linear regression model based on the real terrain factors of various points was considerably higher than that of ordinary kriging prediction method considering the locations of the known points and prediction points. Moreover, the regression model based on vegetation type improved the prediction accuracy of the TN.