Response Of Soil Bacterial Genetic Diversity To Soil Environmental Factors In The Inner Mongolian Steppe

Soil microbes are influenced by various soil abiotic factors at a field plot scale.Little is known, however, the determining factors that influence soil bacterial geneticcommunity diversity at a larger spatial scale of grassland ecosystem. This studyinvestigated the soil bacterial communities responding to different soil abiotic factorson the Eurasian steppe zone. This knowledge plays an important role in understandingthe distribution of soil bacteria community.In this study, a field experiment at a regional scale (Ewenke, Xilinhot, andDamao) was conducted to examine the important factor in affecting soil bacteriadiversity. We obtained the important results and conclusions as follows:(1) Ewenke has the lowest pH value and electric conductivity comparing to thesites of Damao and Xilinhot. And the pH value of Ewenke was slightly acidic whichis6.0. On the contrary, soil organic carbon, total nitrogen, C: N ratio in Ewenke wassignificantly higher than other two sites of Damao and Xilinhot.(2) Soil bacterial community diversity (the bands number of DGGE profile) waslowest in Ewenke comparing to Damao and Xilinhot, which has a similar rule to soilpH value and electric conductivity. And the bands number of Ewenke, Damao andXilinhot were47,54and52, respectively.(3) RDA and regression analysis showed that soil water content, pH value,electric conductivity, soil organic carbon, total nitrogen and C: N ratio were majorabiotic factors influencing soil bacterial communities in Eurasian steppe at a regionalscale. And soil water content, pH value and electric conductivity have positive linearrelationship with soil bacterial diversity. But soil organic carbon, total nitrogen and C:N ratio have negative linear relationship with soil bacterial diversity.Based on the above obtained outcomes from our study, we acquired furtherknowledge and insights into the relationship among microbes and soil environmentalfactors. Different soil environmental factors strongly affected soil microbialcommunity, especially the soil water content, pH value, electric conductivity, totalnitrogen, soil organic carbon and soil C: N ratio, suggesting that soil water content,salinization status and soil nitrogen availability were the major determinants of soilbacterial diversity. In addition, previous studies showed that plant index such as plantdiversity and production was also the important factors influencing soil bacterial diversity. And plant diversity and production can indicate soil water content,salinization status and the resource availability to some extent. It is assumed that soilbacterial community diversity was mainly controlled by soil water, salinization statusand resource availability in the Inner Mongolian steppes at a regional scale.