title: [Effects of nitrogen and water addition on soil bacterial diversity and community structure in temperate grasslands in northern China].
abstract: In this study, we measured the responses of soil bacterial diversity and community structure to nitrogen (N) and water addition in the typical temperate grassland in northern China. Results showed that N addition significantly reduced microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) under regular precipitation treatment. Similar declined trends of MBC and MBN caused by N addition were also found under increased precipitation condition. Nevertheless, water addition alleviated the inhibition by N addition. N addition exerted no significant effects. on bacterial α-diversity indices, including richness, Shannon diversity and evenness index under regular precipitation condition. Precipitation increment tended to increase bacterial α-diversity, and the diversity indices of each N gradient under regular precipitation were much lower than that of the corresponding N addition rate under increased precipitation. Correlation analysis showed that soil moisture, nitrate (NO3(-)-N) and ammonium (NH4+-N) were significantly negatively correlated with bacterial evenness index, and MBC and MBN had a significant positive correlation with bacterial richness and evenness. Non-metric multidimensional scaling (NMDS) ordination illustrated that the bacterial communities were significantly separated by N addition rates, under both water ambient and water addition treatments. Redundancy analysis (RDA) revealed that soil MBC, MBN, pH and NH4+-N were the key environmental factors for shaping bacterial communities.
authors.forename: Shan
authors.initials: S
authors.lastname: Yang
authors.forename: Xiao-bing
authors.initials: XB
authors.lastname: Li
authors.forename: Ru-zhen
authors.initials: RZ
authors.lastname: Wang
authors.forename: Jiang-ping
authors.initials: JP
authors.lastname: Cai
authors.forename: Zhu-wen
authors.initials: ZW
authors.lastname: Xu
authors.forename: Yu-ge
authors.initials: YG
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D064751:Ammonium Compounds / Q000032:analysis; D018533:Biomass; D002244:Carbon / Q000032:analysis; D002681:China; D065948:Grassland; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014867:Water
chemical_list: D064751:Ammonium Compounds; D009566:Nitrates; D012987:Soil; D014867:Water; D002244:Carbon; D009584:Nitrogen