Study on black soil erosion rate and the transformation of soil quality influenced by erosion

The paper investigates the distribution depth of cesium-137 and erosion rate of black soil using cesium-137 tracer, discusses the influence of soil erosion on the contents of particle size, organic matter, specific gravity and water quantity, nitrogen and phosphorus in the tillage layer of 0~20 cm on a typical slope. Cesium-137 activities in the profile, mainly distributed in the layer of 0~25 cm deep, are in the range of 1246.05±85.90 Bq/m 2 to 1499.45±101.73 Bq/m 2 .So,the annual soil erosion rates can reach 3033.6-3940.3 t/km 2 within the last 40 years,which have reached the moderate erosion level. It is the right time to pay enough attention to the black soil erosion. Also, it is completely feasible to investigate the erosion rate of black soil using cesium-137 tracer method. The slope length and gradient have distinctly effects on soil erosion intensity. The trend that the soil particles are becoming increasingly coarser is also obvious. The percentage of sand and clay declines gradually, and silty sand increases from top down to bottom of the slope. Moreover, organic matter (OM) is also in the trend of increase from top to bottom of the slope, but the contents of OM in both erosion and sedimentation profile (2.56~3.10%) are markedly lower than that in original black soil. The specific gravity increases and water content declines in the erosion profile. Furthermore, the phenomenon that the contents of nitrogen and phosphorus decline is clear. Both of the quick degradation of black soil quality and agricultural non-point source pollution should be paid attention to by all circles. Due to the geographical location of black soil belt and its relative location to Pacific and Eurasia, both of frequency and intensity of wind taking place in spring every year are high. So, the above-mentioned soil erosion intensity is the result of wind erosion and water erosion. The percentage of soil quality degradation induced by water erosion and flux of main agricultural non-point source pollutants should be further studied.