放牧对荒漠草原土壤微生物的影响及其季节动态研究

研究了内蒙古荒漠草原不同放牧强度下土壤中微生物数量和养分含量的变化及其季节动态变化。结果表明,草原土壤中各类群微生物数量关系是细菌>自生固氮菌>放线菌>真菌,垂直分布为0~10 cm>10~20 cm土层;土壤微生物和养分含量随季节变化有着明显的变化,但各类群变化规律并不完全相同;与围栏相比,土壤中微生物总数量、细菌、真菌、放线菌和养分含量在轻牧区增加,重牧区降低。自生固氮菌数量在放牧区均增加。

Effects of Grazing on Soil Microorganisms and their Seasonal Changes in Desert Steppe

Changes of soil microorganisms and soil nutrition at different grazing intensities and the seasonal fluctuation in the desert steppe of Inner Mongolia were studied.The results showed that the order of the numbers of soil microorganisms was bacteria>azotobacter>actinomyces>fungi in different soil layers.The numbers of soil microorganisms and the contents of soil nutrients fluctuated apparently with different extents alone with seasonal changes.Compared with non grazing region,the numbers of total microorganisms,bacteria,actinomyces,fungi and soil nutrients increased under light grazing,but decreased under heavy grazing.