中文摘要：

以宁夏贺兰山东麓荒漠贫营养土壤为研究对象,采用PCR-DGGE技术,对土壤中细菌群落和多样性进行了研究。结果表明：不同采样环境土壤中细菌群落组成及多样性存在一定差异,其优势种群均为未培养细菌,且多数分类地位未知。土壤细菌多样性指数和微生物生物量与土壤有机质含量和含水量呈极显著相关（P〈0.01）,有机质含量和含水量是影响贫营养土壤中微生物种类和数量组成的重要因素。

英文摘要：

Taking desert oligotrophic soil from eastern wide of Ningxia Helan Mountain as the research object,by using the way of PCR-DGGE,the community and diversity of soil bacteria were detected.The results showed that there were some differences in the bacteria community and diversity among soil samples which were collected from different sampling environment.All dominant populations of bacteria in soil samples were uncultured and classificatory position of most of them were unknown.Soil bacteria diversity index and microorganisms biomass are significantly correlated to soil organic matter and water content（P〈0.01）.Organic matter and water content were important factors affecting the composition of microorganism＇s species and quantity in oligotrophic soil.