干热河谷泥石流流域不同分区土壤养分特征

The Soil Nutrition Characteristics in Different Partitions of Debris Flow Basin in Dry-Hot Valley

以云南泥石流频发的小江流域为研究区域,根据该流域的微地貌特点,将流域划分为物源区、流通区、堆积区;为全面了解土壤肥力的分区异质性特征,结合各分区土地利用类型,分析其土壤物理结构、养分特征。结果表明:不同分区土壤颗粒组成差异性不大,土壤质地以粗粒和砾石为主,土壤沙石化明显,流通区土壤物理结构相对较好;小江流域山地土壤含水量总体受季节影响较大,而不同分区的土壤含水量则受垂直地带性因素影响,表现为流通区>物源区>堆积区;不同分区土壤养分含量受人类活动、土壤类型、土壤颗粒组成等因素影响,差异性特征复杂,总体含量丰富。

Taking Xiaojiang River watershed as study area where mud-rock flow happens frequently, it was divided into the source area, circulation area and stacked area according to the micro-geomorphic features of the watershed. In order to understand comprehensively the heterogeneity characteristics of soil nutrients in different areas, the physical structure and nutrient properties of the soil were analyzed by integrating with land use types. The results indicated that there were little differences in the composition of soil particles among different partitions, the soil texture was mainly composed of coarse and grave particles, showing prominent desertification. The physical structure of the soil in the circulation area was comparatively better. The soil water content in Xiaojiang River watershed was generally affected by seasonal climate, whereas the soil water content in different partitions was influenced by vertical zonal factors, which was ordered as circulation area 〉 source area 〉 stacked area. The soil nutrition status in Xiaojiang River watershed was generally good with complex heterogeneity, which was integratively influenced by human activities, soil types and soil particle composition.