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为了说明西汉水流域坡耕地侵蚀特征,为流域泥沙管理提供依据,采用137Cs土壤侵蚀核素示踪技术,按野外采样、核素检测、模型计算3步开展研究。结果表明:6块坡耕地剖面的137Cs比活度在某一深度范围内呈较均匀分布,在坡面中上部,137Cs均匀分布的范围与耕层深度接近;6块坡耕地的平均侵蚀模数为2 643~6 419 t/(km2.a),其中1块为强度侵蚀、5块为中度侵蚀;沿坡面自上而下,侵蚀强度从大到小递减;影响坡耕地侵蚀的主要因素是坡度和耕作强度,通常坡度越大,侵蚀模数越大,而耕作强度越小甚至退耕还林,侵蚀模数越小。
In order to explain the erosion characteristics of sloping farmland in the watershed of West Han River, this paper provided the basis for sediment management in the basin. The 137Cs soil erosion radionuclide tracing technique was used to carry out the study in three steps according to field sampling, radionuclide detection and model calculation. The results showed that the specific activity of 137Cs in six sloping fields was distributed more evenly in a certain depth range. In the upper part of the slope, the range of uniform distribution of 137Cs was close to the depth of tillage. The average erosion modulus Which is 2 643 ~ 6 419 t / (km 2 .a), of which 1 is intensive erosion and 5 is moderate erosion. The erosion intensity descends from big to small along the slope from top to bottom. Factors are the slope and tillage intensity, the larger the slope, the greater the erosion modulus, the smaller the tillage intensity and even the conversion of farmland to forest, the smaller the erosion modulus.