土地沙漠化过程的土壤风蚀率指标——以青海共和盆地为例

Soil Wind Erosion Index for Desertification:A Case Study in Gonghe Basin

由风蚀所导致的土壤物质再分配过程,决定了土地沙漠化的程度。根据半干旱干草原地区不同程度沙漠化土地土壤风蚀率的137Cs示踪结果,沙漠化各个阶段的土壤风蚀率指标为:潜在沙漠化土地以微弱堆积和微度风蚀为特征,风蚀率小于2000kg/(hm2·a);轻度沙漠化土地风蚀率介于2000～7000kg/(hm2·a)之间;中度沙漠化土地风蚀率大于7000kg/(hm2·a);重度沙漠化土地风蚀和堆积都很强烈,地表物质交换迅速,没有必要制定风蚀指标。

Desertification grade is basically determined by soil redistribution resulted from wind erosion. Based on cesium-137 tracing results of soil wind erosion rates in steppe area, soil wind erosion index for compartmentalizing desertification grade is tentatively established. Latent desertified land is characterized by weak erosion or deposition, where wind erosion rates are lower than 2000 kg/(hm^2·a). Erosion rates range from 2 000 to 7 000 kg/(hm^2·a) on lightly desertified land and higher than 7 000 kg/(hm^2·a) on moderate desertified land. Seriously desertified land is equivalent to moving sand land where wind erosion and deposition are all very intense, so it is unnecessary to frame a wind erosion index.