闽东南花岗岩侵蚀区的土壤侵蚀与治理 Ⅰ.降雨参数对土壤侵蚀的影响

THE SOIL EROSION AND ITS CONTROL IN THE GRANITE ERODING AREA OF SOUTHEAST FUJIAN Ⅰ. Effect of Rainfall Parameters on Soil Erosion

闽东南花岗岩侵蚀区的侵蚀性降雨集中分布于5～9月份。产生水土流失主要是大于20mm的降雨,尤其是50.1～80和大于100mm的降雨所引起的土壤侵蚀量和径流量占总量的55％。降雨量仅对顺坡抛荒区的土壤侵蚀量产生极显著的影响,同时与顺坡抛荒区、顺坡草区、中耕作物区和灌丛区的径流量成显著的正相关。30min瞬时雨强与顺坡抛荒区和中耕作物区的土壤侵蚀量和径流量成显著的正相关,也与顺坡草区的径流量成显著的正相关。平均雨强对各处理区的土壤侵蚀量和径流量均无显著影响。

The erosion-causing rainfall is concentrated in May to September in the granite eroding area of southeast Fujian. Soil and water loss generally occurred when the rainfall is higher than 20 mm, especially 50.1 to 80 mm and more than 100 mm that the amount of soil erosion or runoff rate caused by them is 55% of the total. The amount of soil erosion is greatly affected by the rainfall only in the uncultiated plot wide up-and-down-slope ridges (UPWUR), and higher rainfall go with greater soil erosion. There exists significantly positive correlation between the rainfall and the runoff rate in the UPWUR and grass plot with wide up-anddown-slope riges (GPWUR), intertilled crop plot (ICP) and bush plot; between the amount of soil erosion or runoff rate and the thirty-minute instantaneous rainfall rate(30 min IRR) UPWUR and ICP and also between 30 min IRR and the runoff rate in the GPWUR. But the amount of soil erosion or runoff rate was unsignificantly related with the mean rainfall rate in each plot.