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培养筛选出一种能够将土壤中铵态氮转化为微生物氮,减少硝态氮形成及N_2O排放的巨大芽孢杆菌Bacillus megaterium,并通过小麦盆栽试验探索该微生物抑制土壤N_2O排放的效果。结果显示:1)高氮肥浓度下,B.megaterium提高土壤中活性微生物数量、种群的相对丰度,降低高浓度氮肥对土壤微生物生长繁殖的抑制作用。2)B.megaterium降低土壤中硝化菌(Nitrospirae)的相对丰度,继而减少硝态氮的形成。3)施加B.megaterium后土壤N_2O排放通量整体小于普通氮肥处理。试验期间B.megaterium处理的N_2O累积排放量较相同氮肥水平下普通氮肥减少4%~53%,且随着氮肥水平的增加,N_2O减排效果逐渐加强。巨大芽孢杆菌B.megaterium可减缓氮肥对气候和土壤环境的影响。
A Bacillus megaterium was isolated and cultured to transform soil ammonium nitrogen into microbial nitrogen and reduce nitrate nitrogen formation and N 2 O emission. The pot experiment was conducted to explore the effect of the microorganism on soil N 2 O emission. The results showed that: 1) Under high nitrogen fertilizer concentration, B.megaterium could increase the number of active microorganisms in soil and the relative abundance of population, and reduce the inhibitory effect of high concentration nitrogen fertilizer on soil microbial growth and reproduction. 2) B. megaterium reduces the relative abundance of Nitrospirae in the soil, which in turn reduces nitrate nitrogen formation. 3) The fluxes of soil N 2 O after B.megaterium application were less than those of ordinary nitrogenous fertilizer. The cumulative N 2 O emissions of B.megaterium decreased by 4% -53% compared with that of common nitrogen fertilizer at the same nitrogen level during the experiment period. With the increase of nitrogen fertilizer level, the emission reduction effect of N 2 O gradually increased. Bacillus megaterium B.megaterium can slow down the impact of nitrogen fertilizer on climate and soil environment.