Effects Of Nitrogen Deposition And Biochar On Soil Microbes In Moso Bamboo Plantations Under Different Management

Soil microbes play a key role in biogeochemical cycles.Nitrogen deposition,biochar and management practices affect the quantity and diversity of soil microbes,which affects the soil material circulation and energy flow.Therefore,we studied the effects of these three factors on soil microbial biomass and microbial diversity in Moso bamboo plantations using high-throughput sequencing.The study showed:?1?Compared with the conventional management?CM?,the soil MBC and microbial diversity were significantly decreased under the intensive management?IM?.The relative abundance of Actinobacteria and Proteobacteria under IM was significantly higher than the CM?P<0.05?.?2?Nitrogen deposition increased the soil MBC,reduced the diversity of soil bacterial,and changed the soil bacterial structure.The MBC showed a tendency to increase first and then decrease with the increase of nitrogen deposition.High nitrogen treatment?N90?significantly reduced the soil bacterial diversity?P<0.05?,increased the relative abundance of Proteobacteria and Crenarchaeota,and decreased the relative abundance of Acidobacteria and Verrucomicrobia.?3?BC20 significantly increased the soil MBC and soil bacterial diversity?P<0.05?,while BC40 significantly reduced MBC,but had no effect on the soil microbial diversity.?4?Biochar amendment reduced the positive effect of nitrogen deposition on MBC,and relieved the negative effect of nitrogen deposition on the soil microbial diversity.Compared no adding biochar,the MBC in combined treatments of BC20 and nitrogen deposition decreased by 6.9%-25.7%,and the diversity increased by 5.9%-9.7%.?5?Soil microbial community was closely related to soil physical and chemical properties.The soil MBC was significantly correlated with soil p H,while soil microbial diversity was significantly correlated with total nitrogen?TN?,C/N ratio and NO₃^-.The bacterial community of Moso bamboo forest was mainly affected by soil p H and NO₃^-.The study showed that IM and N deposition increased the soil MBC and decreased microbial diversity,biochar amendment changed soil MBC and microbial diversity,which largely mitigated the positive effects of N deposition on soil MBC and the negative effects on soil microbial diversity.The study provided an important reference for us to fully understand the response of soil ecosystem of bamboo forest to nitrogen deposition,biochar and management practices.