子午岭林区不同地形部位开垦裸露地降雨侵蚀力的研究

Study on Rainfall Erosivity on the Reclaimed and Bare Land of Different Topographical Location of the Ziwuling Forest Area

在分析了子午岭林区开垦裸露地降雨侵蚀资料的基础上，首次研究了不同地形部位开垦裸露地上的侵蚀性降雨底值，侵蚀性降雨雨型与土壤侵蚀量的关系和降雨侵蚀力定量指标及其与土壤侵蚀量的关系。其结果表明，引起土壤侵蚀的侵蚀性降雨底值次降雨量为１０ｍｍ，Ｉ＿１０为０．４ｍｍ／ｍｉｎ或Ｉ＿３０为０．２５ｍｍ／ｍｉｎ。在侵蚀性降雨雨型中，以突发型侵蚀性降雨雨型引起的侵蚀量最大，其次为峰值型，而以均匀型侵蚀性降雨雨型引起的侵蚀量最小。表示降雨侵蚀力的最好指标无论在梁坡开垦裸露地上，还是在梁坡＋谷坡开垦裸露地上或是在谷坡开垦裸地上均为ＥＩ＿３０。

On the basis of analysing rainfall- erosive data on the reclaimed and bare land of differenttopographic location of the Ziwuling forest area,erosive rainfall background value,relation betweenerosive rainfall forms and soil loss,and quantitative index of rainfall erosivity and relation between itand soil loss have been researched.The results show that erosive rainfall background value caused soilerosion is that rainfall is 10 mm,I_10 0.4mm/min orI_30 0.25mm/min.In the erosive rainfall forms,soilloss caused by sudden change form is the biggest,the next one is caused by peak value form of rainfall,the last one is caused by well- distributed form of rainfall.Whether on the sloping reclaimed and bareland or sloping and valley reclaimed and bare land or valley reclamied and bare land,the best rainfall-erosivity index is EI_30