Screening And Application Of Green Manure Degrading Bacteria From Cruciferae And Leguminosae

Green manure is a clean and harmless source of biological fertilizer,cruciferous and leguminous crops as green manure in the soil,which is conducive to improving soil fertility and improving soil environmental quality,and plays an important role in improving agricultural productivity.However,the direct return of green manure crops to the field has the problem of low straw utilization,and how to screen degrading bacteria that efficiently degrade straw of cruciferous and legume green manure crops,construct composite flora,and explore the optimal fermentation conditions has important theoretical and practical significance for solving the problem of low degradation efficiency of agricultural green manure crops.In this study,single strains with cellulase-producing ability were obtained through preliminary screening using soil in different regions as materials,target strains were determined through enzyme activity rescreening and strain identification,composite flora was constructed,enzyme production conditions were optimized,and the effects of compound fungicides on straw degradation rate,soil and wheat growth were determined in the potting simulated straw return test.This paper aims to construct a composite flora that efficiently degrades cruciferous and legume green manure crops by screening to achieve efficient utilization of green manure to the field.The main findings are as follows:（1）A total of 52 strains were screened from soils in four different areas.After re-screening,the strains with high cellulose degrading ability,the cellulose degrading bacteria in the laboratory and the strains purchased by CGMCC in official website were identified as strain T₁>F₁>E₉>E₁₅>D>C>E₃>C₂>E₁₆>T₃>F>D₇.The strains are mainly divided into Penicillium,Aspergillus Niger and Rhizobium.（2）A complex flora A（T₁+E₉）and E(E₁₆+F)were constructed to degrade rapeseed efficiently;The optimum levels of enzyme production capacity of compound flora A and E were determined as p H 9.0,temperature 25℃and inoculation amount 2%.（3）A complex flora C（D₇+F₁）and a complex flora D(E₁₅+D)were constructed to efficiently degrade alfalfa.The optimum level of enzyme production capacity of compound flora C is p H 9.0,temperature 25℃,and inoculation amount 2%.The optimum level of enzyme production capacity of compound flora D is p H 9.0,temperature 25℃and inoculation amount 3%.（4）Compared with CK,compound microbial inoculum A significantly improved the degradation rate of straw,SPAD value of wheat,number of main roots of wheat and leaf area of wheat;The plant height,maximum root length,fresh weight root-shoot ratio and dry weight root-shoot ratio of wheat were improved.It has no significant effect on soil p H value and soil conductivity.Compared with CK,compound microbial inoculum E significantly improved the degradation rate of straw,the plant height of wheat and the number of main roots of wheat.The SPAD value,maximum root length,leaf area,root-shoot ratio of fresh weight and root-shoot ratio of dry weight of wheat were improved.It has no significant effect on soil p H value and soil conductivity.（5）Compared with CK,compound microbial agent C significantly improved the degradation rate of straw,plant height and SPAD value of wheat;The number of main roots of wheat,the maximum root length of wheat,the root-shoot ratio of fresh weight of wheat,the leaf area of wheat and the root-shoot ratio of dry weight of wheat were improved.It has no significant effect on soil p H value and soil conductivity.Compared with CK,compound microbial agent D significantly improved the degradation rate of straw and the plant height of wheat.The SPAD value,main root number,maximum root length,leaf area,fresh root-shoot ratio and dry root-shoot ratio of wheat were improved.It has no significant effect on soil p H value and soil conductivity.