不同农作措施下红壤坡耕地土壤钾素流失特征的研究

研究了6种农作措施下红壤坡耕地土壤钾素的流失特征．结果表明。红壤坡耕地土壤钾素的地表流失主要是以推移质形式和径流形式流失的；在泥砂流失量较小的等高农作、等高土埂处理的坡耕地。土壤钾素主要以径流形式流失；休闲处理的坡耕地通过径流流失的钾素和推移质流失的钾素基本相当。而在泥砂流失量较大的顺坡农作处、水平草带、水平沟处理的坡耕地土壤钾素主要以推移质形式流失．在径流流失的钾素中。又以泥砂结合态为主．除顺坡农作处理以外，其它农作措施均有控制土壤钾素流失的作用。等高农作、休闲、等高土埂等农作措施优于水平草带和水平沟农作措施．2000年红壤坡耕地土壤钾素的流失时间主要集中在5～8月份．

Properties of potassium loss from red soil slope land in different farming systems

The properties of potassium loss in red soil slope field under six cultivations were studied. The results showed that potassium lost mainly with bed load and runoff on surface of soil. The potassium lost mostly with runoff in slope field under contour, contour dam cultivated ways with less sediment except the fallow, under which the loss of potassium with bed load equaled to the loss of potassium with runoff. The potassium lost mostly with bed load in slope field under straight, grass strip and contour ditch cultivated ways with more sediment, and particulate potassium was the main form of potassium lost in runoff. Compared with straight cultivated way, other cultivated ways reduced soil potassium loss significantly. Contour, fallow, and contour dam cultivated ways were better than straight and grass stripe cultivated ways on controlling potassium loss. In the year of 2000, the potassium loss was mainly occurred during May to August accounting for 87.24-100% of total annual lost.