Effects of nitrogen and water addition on soil bacterial diversity and community structure in temperate grasslands in northern China
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 significandy 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.
temperate grasslandbacterial diversitybacterial community structurenitrogen depositionprecipitation
国家科技期刊平台
NSTL
万方数据
维普
