黄土丘陵沟壑区小流域土壤水分空间变异性及其影响因素

为了解不同土地利用方式和地形条件下土壤含水率的数量特征及其变异规律,以黄土高原丘陵沟壑区纸坊沟小流域为研究对象,利用经典统计学方法系统分析了小流域尺度土壤含水率的空间变异性。结果表明:不同土地利用方式下土壤平均含水率之间呈极显著差异,其顺序为:农田>草地>林地>灌木地;土壤含水率在土壤剖面上呈先减小后增大的趋势。地形条件显著影响土壤含水率,其中梯田>沟底>坡地>峁顶;不同坡位土壤含水率的顺序为坡下>坡上>坡中,不同坡向间为阴坡>阳坡。上述土壤含水量的变异程度均为中等。在小流域尺度,土地利用和地形对土壤水分具有显著的交互作用。相关结果可为黄土丘陵沟壑区的土壤水分管理、土地利用结构优化、不同地形条件下的植被布局提供参考。

Spatial Variability of Soil Moisture and Its Influence Factors in Watershed of Gully Region on the Loess Plateau

To elucidate the quantitative characteristics and variation pattern of soil moisture in different land uses and terrain conditions,classical statistics were used to analyze the spatial variability of soil moisture in small watershed in the gully region of the Loess Plateau.The results indicated that the differences of average soil moisture among different land uses reached the extremely remarkable level,which showed as the order of farm land>grass land>forest land>shrub land.Soil moisture in profiles decreased firstly and then increased.Soil moisture was significantly affected by terrain conditions,which performed as terrace>gully bottom>slope land>the top of hills.Soil moisture was the highest at down slope,next was at up slope,and the lowest was observed at middle slope.Soil moisture on the shady slope was higher than that on the sunny slope.Different land uses and terrain conditions had a significant interaction in terms of soil moisture at the small watershed scale.The results obtained above can provide evidence for soil water management,optimization of land use structure and vegetation deployment in different terrain condition.