Spatial patterns of soil total nitrogen and soil total phosphorus across the entire Loess Plateau region of China

Soil total nitrogen (STN) and soil total phosphorus (STP), which vary spatially at different scales, play important roles in both agriculture and in the natural environment, especially those related to soil productivity and aquatic eutrophication. However, little information is available about the regional spatial availability of SIN and STP and the influence of land use at the regional scale of the Loess Plateau (620,000 km(2)) of China. Therefore, 764 soil samples were collected from 382 sampling sites across the region in order to determine STN, STP and other related soil properties and to relate them to site characteristics. Classical statistics and geostatistics were used to analyze the current status and spatial pattern of STN and SW. Mean STN and SIP concentrations ranged from 0.50 g kg(-1) to 0.81 g kg(-1) and from 0.46 g kg(-1) to 0.61 g kg(-1), respectively, under different land use types. Mean STN and STP densities ranged from 027 kg m(-2) to 039 kg m(-2) and from 0.27 kg m(-2) to 038 kg m(-2), respectively, under different land use types. The concentrations and densities of STN and STP under different land use types were all moderately variable. Land use, precipitation and temperature significantly affected both STN and STP (p