Effects Of Bacterial Inoculation On N₂O In Soil With Organic Fertilizers

Nitrous oxide(N₂O)is a kind of important greenhouse gas that remains in the atmosphere for a long time and destroys the ozone layer.Farmland is an important source of N₂O emission.Controlling its emission has always been a research hot spot all over the world.Using organic fertilizers instead of chemical fertilizers can meet crop nutrient requirements and improve soil at the same time,but N₂O will also be produced as well.In this paper,pure culture experiment and indoor simulation experiment were carried out to inoculate the bacteria with the ability of reducing N₂O emission or promoting N₂O reduction in organic fertilizer,aiming at developing the N₂O emission technology of agricultural soil by using microorganisms to reduce the emission of organic fertilizer.The specific results are as follows:In the microcosmic experiment of organic fertilizer,the tested bacteria and organic fertilizer mixed can reduce N₂O,among which 12 of 33 tested bacteria significantly reduce N₂O.NRCB002 was proved to have the best reduction ability and reduced 82%N₂O compared with the control group.The tested bacteria could still function well in the alkaline environment of organic fertilizer,so we speculated that they had better tolerance under the adverse environment.After studying the growth ability of the tested bacteria in different p H and salinity ranges,we found that the optimum acid-base condition for most strains was neutral alkali-biased(p H=8)and zero salinity.NRCB008 was the most suitable for growing in high alkali environment(p H=10),and NRCB010 was the most suitable for growing in neutral acid environment(p H=6).The strains with the best salinity tolerance were NRCB028 and TSA2S,which could still survive at 10%salinity.In the soil microcosm experiment,we inoculated bacteria into organic fertilizers and applied them to two different types of soil(wheat-corn soil in the North China Plain and rice-wheat rotation soil in the Taihu Lake region)to explore whether these bacteria could still work in the soil system.The results show that the emission reduction effect of the tested bacteria in Yixing area is better than that of Dezhou area.The bacteria with the best emission reduction effect in each area are F1(Dezhou)and NRCB026(Yixing)respectively.Among them,F1 had the best comprehensive performance,and the N₂O emission reduction efficiency were more than 50%in both soils.Inoculating bacteria into soil with organic fertilizer can reduce N₂O emission.Although the emission reduction effect is different under different soil conditions,the tested bacteria were proved to have strong tolerance under adverse environment and can adapt to a wide range of soil types so that a good application prospect can be foreseen..