Effects of soil erosion on soil organic matter and nitrogen in sloping farmland in typical black soil region

Based on the measurement data of soil properties and soil erosion in sloping farmlands of Dongshangou watershed inSonghua River catchment,the correlation between soil erosion and soil organic matter and nitrogenwas analyzed,and the effects of erosion and deposition on the distribution of soil organic matter and nitrogenwere studied.The results showed thatthe distribution of erosion intensity in the whole watershed could be ordered as:upstreammidstream downstream.Along the whole slope,soil erosion intensity varied dramatically in order of slight-severe-slight level. Furthermore,the spatial distribution of soil nutrient contents had a corresponding relationshipwith soil erosion intensity, and it could be ordered as:upstreammidstreamdownstream.The distribution of soil nutrients changed in order of high-low-high level along the whole slope.Soil erosion intensity was negatively related with soil organic matter and total nitrogen at extremely significant level,and with alkaline nitrogen at significant level.This implies that soil erosion has become an important factor causing soil quality decline in black soil region of northeast China.