内蒙古典型草原土壤微生物生物量研究

在内蒙古锡林河流域和皇甫川流域的典型草原,分别以放牧退化梯度和不同植物群落两系列的土壤样品作为研究对象,测定了土壤微生物生物量碳、氮,分析了其与放牧强度和地上植物群落的关系,以及土壤微生物生物量在内蒙古草原的生态分布变化.结果表明,内蒙古草原土壤微生物量碳、氮含量与土壤有机碳、全氮含量具有很好的相关性,可以作为评价草原土壤肥力的生物指标.过度放牧会导致土壤微生物生物量降低.不同地上植物群落维持的土壤微生物量不同.内蒙古草原沿东西走向土壤微生物量总体呈下降趋势.

Soil Microbial Biomass of Typical Grassland in Inner Mongolia

In Xilin fiver basin Leymue chinensis steppe and Huangfuchuan basin typical steppe in Inner Mongolia, two series of soil samples were collected from field with different grazing intensity and different plant community. Soil microbial biomass carbon and nitrogen were determined, the relations between grazing intensity and the plant community on the ground were analyzed, and the change of soil microbial biomass in the Inner Mongolian grassland was also studied. The results obtained by the correlation analysis showed that soil microbial biomass carbon and soil microbial biomass nitrogen had strong positive correlation with soil organic carbon and total nitrogen in steppe. So they could be used as one of bio-indicators of soil fertility. The correlation coefficient of soil microbial biomass carbon and soil organic carbon was 0.907, while the correlation coefficient between soil microbial biomass carbon and soil total nitrogen was 0.942. Excessive grazing re- suited in the decrease of soil microbial biomass significantly. Soil microbial biomass varied with plant communities and showed a decreasing tendency from east to west in the original grassland of Inner Mongolia.