子午岭林区林地和开垦地土壤侵蚀特征研究

Study on Soil Erosion Properties in the Forest Lands and Reclaimed lands

利用大型坡面径流场和小流域的观测资料研究了子午岭林区林地开垦前后土壤侵蚀特征,其结果为林地土壤侵蚀很轻微,侵蚀强度小于15t/(km^2·a),径流模数小于2400m^3/(km^2·a)。地形和降雨特征对土壤侵蚀的影响不甚明显,植被和土壤成为影响土壤侵蚀的决定性因子。而当林地被开垦后,土壤侵蚀由自然植被覆盖下的自然侵蚀转变为人为加速侵蚀,侵蚀模数达1000t/(km^2·a)以上,径流模数在27480m^3/(km^2·a)以上。降雨和地形特征对土壤侵蚀的影响非常明显。土壤加速侵蚀量与10min 或15min 最大雨强(Ⅰ_(10)或Ⅰ_(15))的关系最为密切,坡面汇流增加,谷坡侵蚀产沙系数为27.7%。

Soil erosion properties of forest-lands and reclaimed lands have been researched in this paper,using,observed data of large slope runoff plots and small watershes,The results have shown that soil erosion intensit in the forest land is very slight,soil erosion modulus is less than 15t/km^2·a,runoff modulus is loss than 2400m^3/km^2·a.The factors of vegetation and soil are decided factors of affections soft erosion,but effect of rainfall and topography factors on soil ero- sion is not obvious.After vegetation being destroyed and reclaimed,natural erosion is being changed into accelerated erosion,erosion modulus and runoff moduius are above 10000t/km^2·a and 27 480m^3/km^2·a inspectively.Effect of factors of rainfall and topography on soil erosion is obviousl.soil erosion modulus on the valley is two times that on hilly slope.And soil erosion amount of man-made accelerated erosion is very close relation to I_(10)or I_(15).It is 27.7% that in- creasing sediment of the valley slope erosion of coming from runoff and sediment of hilly slope.