Soil erosion study on hillside in southern Jiangsu Province using the cesium-137 tracer technique

Up to now, there had been little concern about soil erosion in the low mountainous and hilly area of the southern Jiangsu Province. In order to analyze the erosion impacts on the eutrophication of Taihu Lake and on the local soil degradation, the Cs-137 tracer technique was used to investigate the process of soil redistribution (soil erosion and soil deposition) in the study area. In our study, various landforms and different land uses were selected and the local Cs-137 reference inventory of 2,200 Bq m(-2) was determined. Based on the principle of the Cs-137 tracer technique, mass balance models with a definite physical significance for estimating the degree of erosion of cultivated and uncultivated soils were constructed. In contrast to most of the other models, especially the quantitative model of cultivated soil, Cs-137 penetration to the depth below the cultivated layer was taken into account, which might enable to avoid overestimating the erosion rate. The results showed that soil erosion occurred in the southern Jiangsu Province and that the erosion rate of cultivated soil was much higher than that of uncultivated soil. The soil erosion rate in a tea plantation even reached a value of 3,913 Mg km(-2) year(-1). Besides, the results indicated that human activities can accelerate but also mitigate soil erosion.