[目的]研究土壤微生物群落对放牧强度变化的响应机理,为荒漠草原生态保护和修复提供科学的理论和技术支撑。[方法]以内蒙古荒漠草原为研究对象,研究不同放牧强度(未放牧、轻度放牧、中度放牧、重度放牧)对不同深度(0-20,20-40 cm)土壤理化性质和土壤微生物群落组成及多样性的影响,分析土壤理化性质与土壤微生物群落间的交互作用。[结果]相比于未放牧,中度放牧显著降低0-20 cm 土层土壤全氮(TN)和土壤有机碳(TOC)(p<0。05),分别降低17。99%和19。23%,土壤容重(SBD)最大值出现在重度放牧条件下。20-40 cm 土层土壤理化性质在不同放牧强度下并无显著差异(p>0。05)。此外,放牧降低0-20 cm 土层土壤中细菌群落的丰度和多样性,增加20-40 cm 土层土壤细菌中群落的丰度与多样性。轻度和中度放牧条件下,0-20 cm 土层土壤真菌群落的丰度与多样性均有所增加,放牧对20-40 cm 土层土壤真菌群落的丰度与多样性无显著影响(p>0。05)。[结论]Mantel分析表明,荒漠草原土壤全氮是影响草原土壤细菌丰度随放牧强度变化的主要因素。研究成果对揭示土壤微生物在荒漠草原生态系统中的生态敏感性与实现荒漠草原的可持续管理具有一定科学指导意义。
Effects of Grazing Intensity on Soil Microbial Community Characteristics in Desert Steppe
[Objective]Investigating the response mechanism of soil microbial communities to changes in grazing intensity can provide scientific theoretical and technical support for ecological protection and restoration of desert steppe.[Methods]Taking the desert steppe in Inner Mongolia as the research object,we studied the effects of different grazing intensities(no grazing,light grazing,medium grazing,and high grazing)on soil physicochemical properties and the composition and diversity of soil microbial communities at different soil depths(0-20 cm and 20-40 cm),the interactions between soil physicochemical properties and soil microbial communities were analyzed.[Results]Compared to no grazing,medium grazing significantly(p<0.05)reduced the soil total nitrogen(TN)content(by 17.99%)and soil organic carbon(TOC)content(by 19.23%)at 0-20 cm depth.The maximum value of soil bulk density(SBD)appeared under high grazing conditions.The soil physicochemical properties at 20-40 cm depth showed no differences(p>0.05)under different grazing intensities.In addition,grazing decreased the abundance and diversity of bacterial communities at 20-40 cm depth,while increased the abundance and diversity of bacteria communities at 20-40 cm depth.Under light and moderate grazing conditions,the abundance and diversity of soil fungal communities at 0-20 cm depth increased,with no significant effect(p>0.05)on the abundance and diversity of soil fungal communities at 20-40 cm depth.[Conclusion]Mantel tests showed that total nitrogen of desert steppe soil was the primary factor influencing the change of desert steppe soil bacterial abundance with grazing intensity.The research results contribute to understanding the ecological sensitivity of soil microbes and offer scientific guidance for achieving sustainable management in desert steppe ecosystems.