人类活动对锡林郭勒地区主要草原土壤有机碳分布的影响

 内蒙古锡林郭勒地区3类主要草原土壤有机碳含量呈现规律性变化，其顺序为：黑钙土>栗钙土>棕钙土。同时，有机碳沿土壤剖面自上而下逐渐降低，且主要分布在0～15cm处。草甸草原植被下的黑钙土不同层次有机碳含量因农垦分别损失34％～38％，损失主要发生在0～35cm处。分析结果表明，放牧强度在短时期内对典型草原植被下的栗钙土有机碳含量没有显著影响。

DISTRIBUTION OF SOIL ORGANIC CARBON IN THE MAJOR GRASSLANDS OF XILINGUOLE, INNER MONGOLIA, CHINA

The distribution of soil organic carbon in temperate grassland in Xilinguole, Inner Mongolia was examined. Soil organic carbon content varied considerably among the sites and along soil profile. It increased along the gradient from desert steppe, typical steppe to meadow steppe, while it decreased depth. It distributed mainly in 0～15cm of the top soil layer, The effect of landuse pattern on soil organic carbon content Was also investigated. In the meadow steppe, organic carbon of soil (0～35cm) was seriously affected by the conversion of grasslands to croplands. It decreased by 35%～38%. While in the typical steppe area where grazing management works as primary landuse pattern, it was not affected by grazing intensities in the 17 years.