巨大芽孢杆菌对土壤N2O释放量及土壤微生物的影响

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。

Impact of Bacillus megaterium on soil N2O emission and soil microorganisms

Microorganisms such as Bacillus megaterium can convert the ammonium nitrogen into microbial nitrogen andrestrain the formation of nitrate nitrogen and N₂O emission in the soil.To explore the effect of B.megaterium on inhibiting soil N₂O emission, the pot experiments of wheat were conducted.The results showed:1) Under high nitrogen concentration, B.megaterium increased the amount and relative abundance of the active micro-population, and reduced the inhibition effect of high concentration nitrogen fertilizer on the microbial growth and reproduction of the microbial.2) B.megaterium could diminish the relative abundance of nitrifying bacteria (Nitrospirae) in the soil and then inhibit the formation of nitrate nitrogen.3) N₂O emission fluxes in the treatments with B.megaterium were less than that in the ordinary nitrogen treatments.During the whole process in the experiment, under the same nitrogen level, the accumulated N₂O emissions decreased by 4%-53% in the treatments with B.megaterium than that in the ordinary nitrogen treatments.With the increase of nitrogen level, N₂O emission reduction became gradually strengthened.Therefore, B.megaterium retarded the effects of nitrogenous fertilizer on climate and soil environment, especially under high-concentration nitrogen level.