一、绪言 关于降雨对土壤的侵蚀,依据长期以来实地及用人工降雨装置所进行的实验,获得了大量资料和数据。这种侵蚀,它是通过雨滴降于地面时所产生的冲击作用以及雨水在地面上汇集流动所形成的地表水流的搬运作用这两个过程来进行的。为了减少雨滴的侵蚀力,利用植被遮挡地表是有效的。然而根据岩恒雄二、冢本良则等人的研究得出,若是靠大树木起遮挡作用,则其效果会适得其反,因为这样一来小雨滴将会形成大 I. INTRODUCTION With regard to the erosion of soil by rainfall, a large amount of data and data have been obtained based on the experiments carried out on site and with artificial rainfall devices for a long time. This erosion is carried out by two processes, the impact of the raindrops falling to the ground and the handling of surface currents created by the convergence of rainwater on the ground. In order to reduce the erosion of raindrops, the use of vegetation cover the surface is effective. However, according to the study of Yan Heng-xiong and Tsukamoto-dai et al., It can be concluded that the effect will be counterproductive if the trees are obscured by the trees, as this will result in the formation of large