The effect of environmental variables on soil characteristics at different scales in the transition zone of the Loess Plateau in China.

As a result of human disturbance and topographic variability, land use mosaics are characteristic of the transition zone of the Loess Plateau in Shaanxi Province, China. Soils are particularly sensitive to change when land degradation processes are dominant. An understanding of the influences of environmental variables is required to inform land management and agricultural production. In this study the relationships between land type, topography and soil properties were analysed for Hengshan County at two different scales using detrended canonical correspondence analysis. The results show that variations in soil properties are strongly influenced by topography, land use and vegetation. Slope, elevation and aspect are also of importance at the county and small catchment scales of analysis. Though land use type proved to be of lesser importance than topographic factors, ANOVA analysis showed that there were significant differences in soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), available nitrogen, available potassium and clay %. Areas under vegetables had significantly higher SOM and TN content at the catchment scale. The results will enhance our ability to predict spatial and temporal changes in soils. In addition, it is shown that soil fertility could be improved by land reform and management in the hilly-gully area. [ABSTRACT FROM AUTHOR]