祁连山南坡地区土壤有机质含量及赋存特征研究

Study on the Content and Occurrence Characteristics of Soil Organic Matter in the Southern Slope of Qilian Mountains

本文以祁连山南坡地区阿咪东索小流域为研究区,采用野外采样和室内实验相结合的方法对土壤粒度和有机质的含量及赋存特征进行测试,选取林地、草地、灌丛不同类型的生态系统,采集13个土壤剖面土壤样品195个。结果表明:①3个不同生态系统土壤粒度主要为粉砂,其次为砂,黏粒最少,且表层至深层土壤黏粒和粉砂含量逐渐减小,砂粒含量逐渐增加,土壤粒度分布曲线呈非对称双峰分布。②草地生态系统土壤有机质含量最大,灌丛次之,林地最少。随着土层深度的加深,土壤有机质含量呈减小的趋势。③林地、草地和灌丛土壤有机质赋存状态差异较大,表层土壤有机质均以机械混入混合状态为主,至中深层出现差异,林地土壤主要以“有机—无机复合胶体”态存在,而灌丛和草地土壤有机质以“机械混入”和“有机—无机复合胶体”2种状态并存。

Taking Amidonso watershed on the southern slope of Qilian Mountains as the study area,the soil particle size and organic matter content and occurrence characteristics were measured by field sampling and laboratory experiment,195 soil samples were collected from three different types of ecosystems(13 soil profiles),shrub,grassland and forestland,using a combination of field sampling and indoor experiments to measure soil particle size distribution and soil organic matter content.The results show that:①The particle size distribution of the three different ecosystems is mainly silt,followed by sand,with the least clay particles,and the content of clay and silt in the soil from the surface to the deep layer gradually decreases,and the content of sand gradually increases.The particle size distribution curve shows an asymmetric bimodal distribution.②The content of soil organic matter in grassland ecosystem is the largest,followed by shrubs,and forest land is the least.In the same ecosystem,as the depth of the soil layer deepens,the content of soil organic matter tends to decrease.③Forestland,grassland and thickets of soil organic matter occurrence status difference is bigger,the surface layer of soil organic matter are mainly mechanical mixed with mixed state,to difference,deep in soil mainly exist in“organic-inorganic compound colloid”state,and scrub and grassland soil organic matter in“mechanical mixed with”and“organic-inorganic compound colloid”two states co-exist.