放牧对小针茅荒漠草原土壤微生物分布的影响

Dynamic distribution characteristics of soil microorganisms under different grazing intensities in Stipa klemenzii desert grassland

以苏尼特右旗小针茅荒漠草原为样本区域,分别设置无牧、轻度、中度、重度和极重度放牧5种放牧梯度,在生长季（5月~9月）内对不同放牧强度下小针茅荒漠草原三大类土壤微生物（细菌、真菌、放线菌）的分布特征进行了研究。结果表明：不同放牧强度下,小针茅荒漠草原三大类微生物的数量及比例具有明显的季节性分布特征;小针茅荒漠草原土壤微生物数量表现为土壤细菌数量〉放线菌〉真菌,其垂直分布具有明显的差异性,三大类群土壤微生物数量随土层加深而减少;随放牧强度的增加,不同土层三大类群土壤微生物数量均随之减少。

Taking Stipa klemenzii desert - steppe of Sonid Youqi as the research object, the researcher set five different grazing gradients, the non - grazing, mild, moderate, severe and very severe grazing, to study the quantity and dynamic distribution of three categories soil microorganisms （ bacteria, fungi, actinomycetes） in S. klemenzii desert- steppe under different grazing intensities in its growing season （May to September ）. The re- sults showed that with the increase of grazing intensity, the quantity of three groups of different soil microorgan- isms reduced; fencing and improving the soil environment promoted the growth and reproduction of soil microor- ganisms ; the quantity relations of soil microbial in S. klemenzii desert - grassland was that bacteria 〉 actinomy- cetes 〉 fungi, and their distribution had obvious vertical structure, the number of three soil microorganisms pop- ulation decreased with soil depth.