Research Of Reductive Soil Disinfestation Improvement Effect By Exogenous Additives

The core of Reductive Soil Disinfestation is to add easily degradable organic materials into the diseased soil,flood and cover with film,and create strong soil reduction conditions in a short time.It can not only control soil borne diseases,but also change the structure of soil microorganism and improve the physical and chemical properties of soil.It is a kind of soil disinfection method before planting of crops with broad spectrum,high efficiency and environmental friendliness.A large number of studies have shown that it has a significant effect on the control of soil borne diseases,but the RSD method still has some problems such as incomplete removal of Fusarium oxysporum f.sp.cucumerinun.In order to further improve the control effect of RSD,not only corn straw and alfalfa straw,but also organic materials such as arbuscular mycorrhizal fungi,vermicompost and straw degradation agent were added to reform the Reductive Soil Disinfestation.Through the study of soil physical and chemical properties and sterilization effect,this paper explores how to reform the Reductive Soil Disinfestation by exogenous additives,in order to find more effective control methods.The main results are as follows:?1?In the treatment of adding corn straw,the pH of soil increased from 5.29 to 7.0 by adding straw degradation bacteria and vermicompost;in the treatment of adding vermicompost,the content of NO₃^-,SO₄^2-in soil decreased by about 98%,and in the treatment of adding straw degradation bacteria,the content of NH₄⁺in soil increased by 61%;adding vermicompost and straw degradation bacteria significantly increased the content of bacteria and fungi in soil during flooding?91.8%⁹8.2%?,On the contrary,it reduced the content of Fusarium oxysporum f.sp.cucumerinun in the soil by 99.0%compared with the control,and it continued to kill 97.0%of the pathogenic bacteria during the period of falling dry after falling dry;the treatment with straw degrading bacteria significantly improved the control effect of tomato wilt,and the control effect was 85%.The content of vitamin C?90.8%?,total soluble sugar?11.5%?,soluble sugar?15.3%?and organic acid?25.0%?were significantly increased in the treatment of AM fungi.The principal component analysis results showed that the best treatment was the combination of corn straw with straw degradation bacteria,and the worst was the control treatment.In this study,the results of canonical correspondence analysis?CCA?showed that soil SO₄^2-was the main factor driving the reduction of Fusarium oxysporum f.sp.cucumerinun.Therefore,in the RSD method,corn straw combined with straw degradation bacteria can effectively inhibit the growth of Fusarium oxysporum f.sp.cucumerinun in the soil,both before and after flooding,and improve the control effect of tomato fusarium wilt disease.?2?In the treatment of adding alfalfa straw,adding vermicompost,AM fungi and straw degrading bacteria can significantly improve the physical and chemical properties of soil,regulate the composition and structure of soil microorganisms;adding straw degrading bacteria can increase the pH value and NH₄⁺of soil by 30.4%and 75%,adding vermicompost can reduce the content of SO₄^2-in soil by 98%,In addition,the content of soil bacteria and fungi increased by 87.8%-98.3%when straw degradation bacteria were added,Moreover,it not only reduced the total amount of Fusarium oxysporum f.sp.cucumerinun to 0.71‰,but also made the control effect of plant disease reach 86.7%,which was better than the treatment of corn straw with straw degradation bacteria.The content of vitamin C?45.9%?,total soluble sugar?29.3%?,soluble sugar?17.9%?and organic acid?-9.7%?in tomato were significantly increased by the treatment of alfalfa straw with straw degrading bacteria.The principal component analysis results showed that the best treatment was Alfalfa straw with straw degradation bacteria,followed by corn straw with straw degradation bacteria,and the worst was the control treatment.In this study,the results of canonical correspondence analysis?CCA?showed that soil SO₄^2-was the main factor driving the reduction of Fusarium oxysporum f.sp.cucumerinun.Alfalfa straw combination with straw degradation bacteria had the best sterilizing effect on Fusarium oxysporum f.sp.cucumerinun in soil,and significantly increased the control effect of wilt disease,tomato quality and tomato plant biomass,and reduced the incidence rate of tomato fusarium wilt disease.In summary,corn straw,alfalfa straw combined with vermicompost,AM fungi and straw degradation bacteria can significantly improve the control effect of Reductive Soil Disinfestation on tomato fusarium wilt disease,The treatments of adding straw degradation bacteria significantly reduced the incidence rate of tomato fusarium wilt disease.Further comprehensive analysis showed that the treatment of adding alfalfa straw combined with straw degrading bacteria had the best effect,which could significantly reduce the number of Fusarium oxysporum f.sp.cucumerinun,improve tomato growth and tomato quality.This combination has a very broad application prospect and research and development value in in aspect of control of tomato fusarium wilt disease.