基于土地利用变化的县域水土流失消长评价方法探讨

以人类活动扰动比较大的内蒙古自治区达拉特旗和人类活动扰动比较小的青海省称多县为例,收集了2014—2015年和2017年土地利用、遥感影像等资料,采用中国土壤流失方程计算了水力侵蚀模数。在此基础上,分析了2017年与2014—2015年土地利用和水土流失面积的差异,对比了基于两期土地利用图和基于遥感影像变化得到的水土流失消长变化之间的差异。结果表明:基于两期土地利用图得到水土流失面积变化大,基于遥感影像变化得到的水土流失面积变化小,前者水土流失面积变化量是后者的64倍(称多县)和94倍(达拉特旗)。基于遥感影像变化得到的水土流失面积消长结果更符合实际情况。水土流失面积消长量远小于土地利用面积变化量。本结果可为即将开展的全国水土流失消长评价工作提供技术参考。

Evaluation Method of Variation of Soil Loss for a County Scale Based on the Land Use Change

In this study, Dalateqi County in Inner Magnolia which stands for highly intensity human activity and Chengduo County in Qinghai Province which is for low intensity human activity were selected as study areas. The data on land use and remote image in 2014-2015 and 2017 were collected. The soil loss was calculated using Chinese soil loss equation. The variation of land use and soil loss was analyzed. The differences in soil loss and land use were compared based on the two period land use results (LUR) and on the two period remote image variation results (IVR). The results showed that variation of soil loss based on the LUR was more obvious than that on the IVR. The area variation of soil loss based on the LUR was 64 times (Chengduo) and 94 times (Dalateqi) of that on the IVR. The area variation of soil loss based on the IVR was more reasonable, which reflected the true variation. The area variation of soil loss was far smaller than that of land use. The results will provide the technique support for the evaluation method on the incoming annual variation of soil loss according to the "soil loss inventory plan in China (2018-2022)".