不同植被盖度下的黄土高原土壤侵蚀特征分析

利用地理信息系统(GIS)技术对黄土高原土壤侵蚀空间数据和植被盖度等级数据进行了空间叠加,研究不同盖度的植被对土壤侵蚀的影响。结果表明:植被盖度等级为1时,黄土高原土壤侵蚀全部为水蚀,占整个土壤侵蚀的100%;植被盖度等级为2时,土壤侵蚀主要以水蚀为主,占整个土壤侵蚀的95.61%;植被盖度等级为3、4、5时,土壤侵蚀仍主要以水蚀为主,分别占整个土壤侵蚀的74.90%、66.68%和58.19%。冻融侵蚀出现在植被盖度等级为4和5时,占整个土壤侵蚀的比例均不大。随着植被盖度的增加水蚀所占比重逐渐减小,而风蚀、水?风混合侵蚀和冻融侵蚀所占比重逐渐加大。植被盖度等级为5时,水蚀、风蚀和水-风混合侵蚀的土壤侵蚀指数均比其他植被盖度等级的土壤侵蚀指数大,分别为657.56、796.68和596.79,土壤侵蚀最严重。黄土高原植被盖度变化对土壤侵蚀状况影响显著。

Soil erosion characteristics under different vegetation coverage in the Loess Plateau

The relationship between vegetation coverage and soil erosion in the Loess Plateau was determined via spatial overlay analysis on Geographical Information System platform. Water erosion accounts for 100% of all erosion in vegetation coverage grade 1; 95.61% in vegetation coverage grade 2, and 74.90%, 66.68% and 58.19% in vegetation coverage grade 3, 4 and 5 respectively. Frozen erosion is mainly distributed in vegetation coverage grade 4 and 5. With increase in vegetation coverage grade, the proportion of water erosion gradually decreases while those of wind, water-wind, and frozen erosion gradually increase. The soil erosion indexes of water erosion, wind erosion and water-wind erosion for vegetation coverage grade 5 are 657.56, 796.68 and 596.79 respec-tively-much higher than those for the rest vegetation coverage grades. Soil erosion is most severe for vegetation coverage grade 5. Change in vegetation coverage has a significant impact on soil erosion in the Loess Plateau.