人为干扰对典型草原生态系统土壤养分状况的影响

从土壤N，P，K及土壤有机质等方面研究了人为干扰（包括放牧、开垦和禁牧）对典型草原生态系统土壤养分含量的影响。研究结果表明：开垦和放牧会导致土壤，主要是表层土壤养分含量的下降，而开垦对土壤养分的影响更为明显；禁牧会提高土壤各种养分的含量，而且随着禁牧时间的增加，土壤养分含量有逐渐增加的趋势。对深层土壤养分含量没有明显影响。同时，草原生态系统土壤全氮、速效氮及有机质含量与土层深度呈明显的负直线相关关系；速效K、速效P含量则与土壤深度的关系符合二次幂函数关系；全磷含量随深度的增加有逐渐升高的趋势；土壤全钾含量随土壤深度的增加呈微弱的降低趋势，但变化不明显。本研究表明，禁牧可以提高典型草原土壤养分元素的含量，有利于遏制草原土壤的退化。

Impact of Human Disturbances on Soil Nutrient Contents of Typical Grasslands

The impact of human disturbances including grazing,cultivation and anti-grazing(from 1987,1997,2003 respectively) on nutrients contents(N,P,K and organic matter) in typical grassland soil was studied in the paper.The result showed that cultivation and grazing can lead to a decrease in nutrient contents of soil,especially topsoil,and cultivation affects it more significantly than grazing;Banned-grazing can increase nutrients contents of soil,which increase with banned-grazing period.At the same time,there exist significant minuslinear dependency relationship between the total N,available N,organic matter and soil depth;there exist second power function relation between available P,available K and soil depth.The total P contents increases with the soil depth,and the total K decreases with it,but the dependency relations were not significant.It is concluded that anti-grazing can increase the nutrient contents in grassland soil and restrain the degradation of grassland soil.