Effects of grazing intensity on spatial variation of organic carbon and total nitrogen contents of soil

The objective of present study was to determine soil total carbon (C) and nitrogen (N) contents under different grazing densities and analyze the effects of grazing density on spatial variation of soil C and N contents in light chestnut soil by geostatistics. The results indicated that soil C and N contents varied in a moderate grazing degree. With the increasing of grazing intensity, soil C and N contents decreased. Regional factors caused a large spatial variation in soil C and N contents under (none grazing) control, moderate grazing density and heavy grazing density. However, the spatial variation of soil C and N contents under light grazing density was mainly due to interaction of regional factors and random faltor of grazing, which belonged to moderate spatial correlations. Generally, the ranking of variation of soil C and N contents was controllight grazingmoderate grazingheavy grazing. The patch areas with low soil C and N contents increased in the regions of moderate grazing and heavy grazing year by year. Thus, it is suitable to conduct a light grazing in this area.