草甸草原不同放牧强度对土壤有机碳含量的影响

The effects of different grazing intensity on soil organic carbon content in meadow steppe

对草甸草原土壤有机碳（SOC）、全氮（TN）和机械组成的研究结果表明,土壤表层（0-20 cm）的有机碳和全氮在轻度放牧和中度放牧的情况下没有显著差异,但都显著高于重度放牧的草地。草地植被则表现为：轻度放牧显著高于中度放牧,中度放牧显著高于重度放牧草地。因此,中度放牧草地是草地退化的警戒阈,应当引起关注。在土壤表层（0-20 cm）,SOC和TN有显著地线性相关关系,两者与土壤机械组成没有显著的线性相关关系。

Soil organic carbon （SOC）, total nitrogen （TN） and mechanical composition Meadow steppe soil were studied, which showed that SOC and TN of surface soil（0--20 cm）had no significant difference under light and moderate grazing, but significantly higher than that on heavy grazed land. The grassland vegetation coverage was higher under light grazing compared to moderate and heavy grazing. So moderately grazed grassland was the threshold and should be addressed. SOC of surface soil（0--20 cm）linearly correIated to TN but they had no significant linear correlation to mechanical composition.