人工降雨条件下南方坡耕地水土流失特征

Soil erosion features of slope land in the South of China under artificial precipitation

利用稀土示踪技术和径流小区法在人工降雨条件下研究南方地区坡耕地水土流失特征.研究发现:坡面侵蚀量与降雨强度有关;坡面侵蚀泥沙主要来自坡面的中部和下部,其中坡面上部只占总侵蚀量的10%左右,而中坡和下坡占总侵蚀量的90%左右,下坡侵蚀量最大,占总侵蚀量50%左右;降雨强度、土壤团聚结构、渗透率和土壤含水量导致第一次人工降雨的侵蚀量、侵蚀泥沙中各稀土元素的含量最大;第二次人工降雨的侵蚀量比第一次人工降雨的小,但比后面3次人工降雨的侵蚀量大.同时探讨了南方地区侵蚀研究的重要性和特点、人工降雨所测结果的应用,以及侵蚀泥沙来自于中部和下部的机理.

Run-off plot and rare earth elements tracing technology were used under artificial precipitation to study the slope land erosion in the South of China. The results showed that the erosion of slope land is correspond with intensity of the rainfall. Soil loss is mainly sourced from the down slope and mid- slope, and it accounts for approximately 90% of total. The upper slope only accounts for about 10%, and the down slope can reach about 50%. Impacted by the rainfall intensity, soil aggregate structure, permeability, and moisture, the quantity of soil erosion and content of rare earth elements are biggest in the first rainfall event, and lower in the second rainfall event than that in the first event but higher than that in other three rainfall events. Meanwhile, the following problems such as the importance and features of the erosion in the South of China, application of research results under artificial precipitation, the mechanism of sediment source in the slope were also discussed.