关键词: 放牧, 荒漠草地, 土壤理化性状, 阿拉善

Abstract: Soil physical and chemical properties of desert grassland with different grazing management systems were studied at Alxa Prefecture, Inner Mongolian Autonomous Region. The results showed that started from the similar grassland conditions soil bulk density of medium grazed paddocks at 0~20 cm depth was higher than those of light and heavy grazed paddocks six years after grazed with different stock rates. As grazing intensity increased the proportions of extremely coarse, coarse and medium size sandy particles were increased, while the contents of fine and extremely fine sandy particles, silt particle and clay particle were decreased. This indicated that overgrazing accelerated the process of soil wind erosion and desertification. The contents of organic matter, total P and C/N at 0 ~ 20 cm depth decreased as the grazing intensity increased. No significantly differences in the contents of total N, total K and pH were detected among the paddocks with different grazing intensity. However, the contents of available N and available K in the soil of heavy grazed paddocks were higher than those in the light and medium grazed paddocks. On the other hand, the contents of available P in the light grazed paddock is the highest, which is followed by the medium and heavy grazed paddocks. Significantly positive correlations were found between soil organic matter and contents of total P, available P, and between contents of total P and available P. Significantly negative correlations were existed between the contents of total P and available N, and available K., respectively.

Key words: grazing, desert grassland, soil physical and chemical property, Alxa Desert