三江源区不同退化程度高寒草地土壤特征分析

Characteristics of Soil on Different Degraded Grasslands on Alpine Meadow in Source Area of Lancang,Yellow and Yangtze River

研究了不同退化程度高寒草地不同土层的土壤特征。结果表明,三江源区高寒生态条件下草地退化对土壤物理、化学特征具有较为明显的影响。在0～30 cm土层,不同退化程度高寒草地土壤容重、含水量、总孔隙度差异显著。土壤容重随高寒草地退化程度的加剧和土壤深度的增加而增大,变动范围为1.02～1.61 g/cm3;土壤含水量、土壤总孔隙度随高寒草地退化程度的加剧而减小,变动范围分别为13.98%～70.75%、40.82%～60.29%;土壤pH总体随高寒草地退化程度的加剧而增大;土壤有机碳含量随高寒草地退化程度的加剧而下降,以0～10 cm土层下降最明显,轻度、中度和重度退化高寒草地该土层有机碳含量与未退化草地相比,分别下降36.05%、61.82%、66.55%;不同退化程度高寒草地土壤全氮、全磷、全钾含量总体为未退化草地>轻度退化草地>中度退化草地>重度退化草地。

Characteristics of soil in different degradation grassland on alpine meadow were analyzed based on different soil layers. The results showed that under the ecological conditions of source area of Lancang, Yellow and Yangtze river, Alpine meadow degradation had marked effects on soil physical and chemical characteristics. The soil bulk density, moisture content, total porosity in 0-30cm soil layer of the different degraded alpine meadow were significantly different. Soil bulk density in- creased with the aggravation of degraded alpine meadow and also increased with the increment of soil depth. The correspond- ing values ranged from 1.02 to 1.61 g/cm^3. The soil moisture content and total porosity decreased with the aggravation of de- graded alpine meadow, their range values were 13.98%-70.75%, 40.82%-60.29% respectively. Soil pH increased gradually with the expansion of degradation degree. Content of SOC （0-10 cm） was highest in undegraded alpine meadow, while 36.05%, 61.82% and 66.55% decreased in light, moderately and heavy degradation alpine meadow compared with undegraded alpine meadow respectively. The tendency of total N ,total P and total K contents in different degradation alpine pasture were undegraded meadow 〉 light degraded meadow 〉 moderately degraded meadow 〉 heavy degraded meadow.