用人工模拟降雨研究不同土壤类型的产沙特征

以新疆伊宁、玛纳斯县3种土壤类型为研究材料,采用室外人工模拟降雨试验、野外调查采样与土壤样品室内理化性质测定相结合的方法,比较了相同降雨条件下3种类型土壤的坡面侵蚀特征。结果表明:(1)土壤的颗粒组成和有机质含量是影响土壤可蚀性差异的主要因素。土壤中粉粒的含量越高,其含沙量、可蚀性K值愈大,越易发生侵蚀;土壤中粘粒含量越高,土壤含沙量、可蚀性K值越小,越易抵抗侵蚀。(2)相关性分析发现土壤的径流速率和产沙量的相关系数为0.56,没有显著的相关性。(3)土壤的有机质和累积含沙总量相关性分析,发现两者显著相关,相关系数为0.73。(4)通过打破土壤结构体,发现2 mm结构体土壤中,灰钙土的产流速率、产沙量及可蚀性K值均最小;2 mm土壤结构体中,棕钙土的产流速率、产沙量及可蚀性K值均最小,且2 mm土壤结构体比2 mm结构体的土壤抵抗侵蚀的能力大。

Study on sediment yield characteristics in different soils using simulated rainfall

Three soils in Yining County and Manas County were used as study materials. By using outdoor artificial simulated rainfall experiments, a field investigation and sampling as well as determination of physicochemical properties of soil samples in lab was conducted to compare the erosion characteristics of the three soils. Results showed that: (1) The particle composition and soil organic matter were the main factors influencing the difference in soil erodibility (K). The higher the silt content, the higher the sediment concentration and K value, which meant much easier to cause soil erosion. On the contrast, the higher the clay content in the soil, the smaller the sediment concentration and K value, which meant much easier to produce soil anti-rosion. (2) A correlation analysis showed that the correlation coefficient of runoff rate and sediment yield was 0.56, without a significant difference. (3) The soil organic matter and cumulative total sediment had a significant correlation, with the correlation coefficient of 0.73. (4) By breaking the soil aggregates, we found the three types of soils with >2 mm soil aggregates, runoff rate, sediment yield and K value of Gray calcium soil were all the least; while the soils with <2 mm soil aggregates, runoff rate, sediment yield and K value of Brown calcium soil were all the least. The anti-erosion of the soil with >2 mm soil aggregates was larger than that of the soil with <2 mm soil aggregates.