我国水蚀区坡耕地土壤分离能力的空间分布与影响因素

Spatial Distribution and Influencing Factors of Soil Detachment Capacity of Sloping Farmland in Water Erosion Zone of China

我国水蚀区不同区域自然地理环境和土壤理化性质存在巨大差异,可能会引起土壤分离能力(Dc)的差异。然而目前大尺度上(如水蚀区)Dc的空间分布及其影响因素的研究尚未见报道。在水蚀区依据土壤类型和土壤质地不同布设了36个采样点,用扰动土(代表新耕坡耕地)测定其Dc并分析其影响因素。结果表明,水蚀区沙漠风沙土Dc最大,红壤Dc最小,Dc呈强度空间变异。西北黄土高原地区和南方山地丘陵区Dc最大。黏粒和砂粒含量适中的土壤质地Dc最大。水流剪切力与水流功率在模拟Dc方面无显著差异。Dc与粉粒、土壤粒径参数、阳离子交换量和土壤有机质存在显著的负相关关系,与砂粒、中值粒径、平均几何粒径和交换性纳百分比存在显著的正相关关系。水蚀区Dc可用水流剪切力、粉粒、阳离子交换量和土壤有机质很好地模拟(R^2=0.71,NSE=0.71)。

There are enormous differences in natural geographical environment and soil physciochemical properties in different regions of the water erosion zone in China,which may cause differences in soil detachment capacity(Dc).However,little research has paid attention to the spatial distribution of Dcand its influencing factors at large scale(such as the water erosion region).In this study,36 sampling sites were selected in the water erosion zone according to the soil types and soil texture.Dcwas measured by disturbing soils(representing freshly tilled sloping farmland)and the influencing factors were analyzed.The results showed that Dcof Aqui-Sandic Primosols was the largest,while that of Argi-Udic Ferrosols was the smallest,and Dc exhibited a strong spatial variation in the water erosion zone.The northwest Loess Plateau and the South Hilly Area had the largest Dc.The soil texture with moderate content of clay and sand had the largest Dc.There was no significant difference between shear stress and stream power in simulating Dc.Dc had a significant negative correlation with silt content,particle size parameter,cation exchange capacity and soil organic matter,and a significant positive correlation with sand content,median soil grain size,geometric mean particle diameter,and exchangeable sodium percentage.Dcin water erosion area could be well simulated by shear stress,silt content,cation exchange capacity and soil organic matter(R^2=0.71,NSE=0.71).