黄土丘陵小流域土地利用变化的土壤侵蚀效应: 基于137Cs示踪的定量评价

基于¹³⁷Cs示踪技术，结合土地利用变化数据，对黄土丘陵沟壑区羊圈沟小流域土壤侵蚀强度的演变过程进行了研究.结果表明：从20世纪80年代以来，该流域土地利用强度逐渐减弱;1980—2006年间，研究区坡耕地面积急剧下降，从94.9 hm²下降到0.2 hm²，乔木林地面积由0增加到51.1 hm²，灌木林地面积由0增加到19.2 hm²，果园林地面积由0增加到18.0 hm²，荒草地面积趋于稳定，由76.9 hm²增加到80.1 hm².研究期间，不同土地利用类型的土壤侵蚀强度依次为:坡耕地>灌木林地>果园林地>荒草地>乔木林地;1980、1984、1996和2006年流域土壤侵蚀强度分别为6408.9、5362.4、4903.9和3641.4 t·km^-2·a^-1,侵蚀程度由强度变为中度.土壤侵蚀强度降低的主要原因是该区的水保措施和植被恢复措施.

Effects of land use change on soil erosion intensity in small watershed of Loess Hilly Region: A quantitative evaluation with 137-Cesium tracer

Based on the land use change data and by using 137Cs tracer technique, this paper studied the change process of soil erosion intensity in Yangjuangou watershed in Loess Hilly Region. Since the 1980's, the land use intensity in the watershed decreased gradually. In 1980-2006, the slope arable land decreased from 94.9 hm2 to 0.2 hm2, while the forest land, shrub land, orchard land, and grassland increased from 0 to 51.1 hm2, from 0 to 19.2 hm2, from 0 to 18.0 hm2, and from 76.9 hm2 to 80.1 hm2, respectively. The soil erosion intensity was in the order of slope arable land > shrub land > orchard land > grass land > forest land. In 1980, 1984, 1996, and 2006, the soil erosion intensity was 6408.9, 5362.4, 4903.9, and 3641.4 t·km-2·a-1, respectively, being changed from intense to moderate. Soil and water conservation and vegetation restoration were the main causes of the decrease of soil erosion intensity in the study area.