青海黄土丘陵区沟蚀侵蚀模数与其影响因子关系分析

The relationship between the erosion modulus and the influence factors in the loess hilly and gully area

以青海黄土丘陵区18条侵蚀沟为研究对象,用钢钎法测定了侵蚀模数,根据样地土壤砂粒、粉粒、粘粒质地分布和有机质的质量分数,分析计算其可蚀性K值。结合样地植被、坡度等调查信息,分析侵蚀模数与其影响因子的关系。结果表明:同一时期,侵蚀模数随植被覆盖度的增加而降低,当植物覆盖度达到70%时,侵蚀模数对植被因子的敏感度降低。侵蚀模数随土壤孔隙度的增大而降低。随K值的增大和坡度的升高,侵蚀模数有增大的趋势。不同时期,高植被覆盖的样地,侵蚀模数随年限的增加呈降低趋势;低植被覆盖的样地,侵蚀模数随年限的增加呈波动变化,但总体上呈下降趋势;无植被覆盖的侵蚀沟样地,年侵蚀模数没有降低趋势。植被覆盖度相当的样地,K值越小,侵蚀模数越小。

18 erosion ditches in Loess Hilly and Gully area of Qinghai province were investigated with the drill rod method. The erosion modulus was measured according to the massfraction of soil particles with different diam- eters, combined with the information such as tree species and slops to analyze the interrelationship between the erosion modulus and other influencing factors. The results showed that the erosion modulus decreased as the cover- age increased, and when the coverage was up to 70%, the sensitivity that the erosion modulus respond to the trees went down. Moreover, the erosion modulus decreased as the porosity of the soil expanded. With the increase of the K value and the grade of the slop, the value of the erosion modulus tended to go up. The value of the erosion modulus decreased in the plots of erosion ditches with high coverage year by year, the value of the e- rosion modulus kept the same in the plots of erosion ditches with no coverage, and the erosion modulus decreased as the value of K got depreciated in the plots of erosion ditches with same coverage.