【摘要】 <正> 降雨侵蚀是降雨和土壤的相互作用。降雨的作用称为侵蚀力,土壤的作用称为可蚀性。具体地讲,降雨侵蚀力是指降雨引起侵蚀的潜在能力,土壤可蚀性是指土壤对侵蚀的易损性或敏感性,在通用土壤流失方程式中二者分别用R和K麦示。对于降雨侵蚀力R的研究,国外开展较早。美国学者威斯其迈尔（Wischmier）找出了降雨的动能与其30分钟最大强度的乘积是判断土壤流失的最好指标,其表达式为R=∑EI₃₀。这个计算式是用美国的资料更多还原

【Abstract】 The index of erosivity of rain （ R ） is a most important factor in the equation of soil erosion used in the United States.Based on data observed in 13 consecutive years 1957 through 1970 at Yangdaogou in Lishi, W .Shanxi, analysis made by the authors proved that the equation R= ∑EI₃0 employed in the United States does not apply to gullied rolling loess regioo in W.Shanxi, whereas the expression of R=∑EI₁0 has been found to be more fitting for forecasts of soil erosion of croplands in the aforementioned area. Long-term average yearly and mo thly values of R are also determined.更多还原