中文摘要：

本研究以我国古尔班通古特沙漠东南缘原生梭梭生长区为研究区,通过模拟30%的年降雨量增加和5 g N m^-2·yr^-1的氮沉降,研究土壤微生物生物量和土壤细菌群落多样性和结构对模拟降水增加和氮沉降的响应.研究结果表明,模拟降雨增加显著提高了春季短生植物和春夏一年生植物生长旺季土壤微生物生物量碳和氮,模拟氮沉降对微生物生物量的影响非常微弱,与单独模拟降水增加相比较,降水和氮沉降同时增加对微生物生物量并没有显著影响.模拟降水增加和氮沉降对细菌多样性的影响因采样时段而异.模拟降水增加在春季短生植物和春夏一年生植物生长旺季对细菌多样性的影响强度高于冬季和早春融雪期,模拟氮沉降对细菌多样性的影响在冬季更为显著.微生物群落结构在不同采样时段表现出明显的不同,虽然模拟降水增加和氮沉降也影响微生物群落结构,但影响强度不如季节变化明显.

英文摘要：

Selecting protogenesis sacsaoul growing region of the southeastern fringe of the Gurbantünggüt Desert as research area. Simulating a 30% increase in precipitationand 5 g N·m^- 2·yr^- 1 nitrogen deposition,the paper studies soil microbial biomass,bacterial community diversity and structure responses to the increase in annual precipitation and nitrogen deposition alone. The result shows simulating precipitation increased soil microbial biomass carbon and nitrogen at the growth peaks of spring ephemerals and spring- summer annuals,while nitrogen deposition at a rate of 5 g N·m^- 2·yr^- 1 has a weak effect on soil microbial biomass; precipitation addition and nitrogen deposition in combination has similar effects on soil microbial biomass with precipitation addition alone. Precipitation addition and nitrogen deposition effects on bacterial diversity differing with regard to the different sampling time. Precipitation addition had significantly stronger influence at growth peaks of spring ephemerals and spring- summer annuals than that in winter and snowmelting,while nitrogen deposition had stronger effects on bacterial diversity in winter. Soil bacterial community shows large variations with sampling times,although precipitation addition and nitrogen addition also altered bacterial community composition,its effects are much weaker than the sampling duration in this study.