Jiangxi Red Soil Region Dual Nuclide Tracer Soil Erosion Research

As an important base of tropical and subtropical economic forest, cash crops and food production, the southern red hilly region is one of the most serious soil and water loss areas in China. In this region, the increasingly serious soil erosion and its secondary products soil degradation and reduced productivity cause widespread concern. Therefore, reaching about law of southern red soil region has a vital significance for controlling area water and soil losses and improving soil quality.Made a small basin in Jiangxi red soil region as object, the paper studies vertical and spatial distribution law, soil erosion rate and analyzes affect soil erosion factors including land use utilizing composite tracer technology of137Cs and210Pbex, topography and so on, with combination methods of field data and samples collection, indoor processing, test, analysis, mathematical statistic and calculation. The conclusions as follows:1. Different land use, different radionuclide content in vertical and spatial distribution, which is paddy field> turnip land> peanut land> sweet potato land> sesame land in cultivated land, while in uncultivated land is bamboo forest> flood plain> orange forest. Besides, the distribution condition of210Pbex and137Cs are almost the same to each other.2. Beside the research area, the author collect nine samples in a paddy field to determine that the background value of137Cs and210Pbex are1746.64Bq/m2and44383.83Bq/m2, respectively. By contrast, it is believed that Yang H model concerns more factors than Zhang X B’s in cultivated land of137Cs, so finally the paper choice Yang’s. In terms of a few researches experiment about soil erosion using Pbex technology and area similarity, the stable state model is selected for rbex tracing soil erosion study.3. Because of approximate results using two different radionuclide tracers, it’s proved that210Pbex tracing soil erosion in this area is feasible. Then, soil erosion rates under different land uses are obtained using arithmetic average method. According to adjusted intensity grading standard for water erosion, it’s confirmed that sweet potato and sesame lands suffer the strongest erosion, turnip and peanut land and the upper of paddy field suffer the stronger erosion, floodplain suffers moderate erosion, orange woodland and bamboo forest suffer mild erosion.4. Different land use, vegetation cover, terrain factors and so on influence soil erosion which lead to the loss of soil nutrients. There is a positive correlation between soil erosion rate and inclination. In the same case of vegetation cover, inclination and rainfall, with the increase slope length and surface runoff, soil erosion will strengthen.In addition, there are negative correlations between organic matter content and210Pbex soil erosion rate, soil total nitrogen content and137Cs、210Pbex erosion rates.