Effect Of The Combined Application Of Fungal Residues And Chemical Fertilizers On The Soil Organic Carbon Stability、enzyme Activity And Microbial Diversity Yield In Paddy Fields

As an excellent organic material additive to soil,fungal residue can reduce the application of chemical fertilizer,maintain the stability of soil organic carbon components and also plays an important role in maintaining soil fertility.Therefore,it is important on evaluating the ecological significance of the fungal residue on soil by exploring the effects of different proportions of fungal residue and chemical fertilizers on soil enzyme activities,organic carbon stability and microbial diversity during the rice growth period over a long-term scale.In this study,a long-term location experiment in paddy field was carried out in which a randomized complete block field experiment with nine treatments（0,50%,and 100%levels of chemical fertilizers（C）and edible fungal residue（F）were considered,C100F50 stands for 100%of chemical fertilizer and 50%of fungal residue application,etc.）was set up.Soil microbial biomass carbon（MBC）,soluble carbon（DOC）,alkoxy carbon,alkyl carbon,aromatic carbon and carbonyl carbon were measured.The changes of catalase,sucrase,urease and acid phosphatase activities in the soils treated in the main growth stages of rice were also analyzed,And the interactive effect of the combined application of fungal residue and fertilizer on soil enzyme activity.At the same time,the community characteristics and diversity index of soil fungi and bacteria were measured,The correlation between soil active carbon bank organic carbon components,soil enzyme activity and soil microbial community characteristics and soil environmental factors was analyzed.The main results are as follows:（1）The content of soil microbial biomass carbon,dissolved organic carbon,alkoxy carbon,alkyl carbon and aromatic carbonwas significantly increased by applying fungal residue and chemical fertilizer.The highest increases were 38.74%,35.67%,11.93%,13.08%and 29.79%.Microbial biomass carbon,soluble carbon and alkoxy carbon are highest in C₁₀₀F₅₀,alkyl carbon is largest in C₁₀₀F₁₀₀,and aromatic carbon is largest in C₅₀F₁₀₀.However,there will be a downward trend under high amounts of bacterial residues or chemical fertilizers.Compared with the single application of chemical fertilizers,the treatment of MBC/SOC and DOC/SOC by the combined application of bacterial residues and chemical fertilizers decreased.In addition,there are extremely significant positive correlations between different forms of organic carbon components（P<0.01）,among which aromatic carbon has the strongest correlation with MBC.There was a significant positive correlation between different forms of organic carbon components and soil physical and chemical factors.（2）The combination of fungal residue and chemical fertilizer can increase the activities of soil catalase,sucrase,urease and acid phosphatase,and with the increase of the application amount,the trend of increasing first and then decreasing;The contents of catalase,sucrase,urease and acid phosphataseactivities varied from 3.01 to 10.018ml/g,0.20 to 2.04mg/g,0.54 to 4.80mg/g and 2.84-4.36mg/g respectively.Among them,The activities of catalase and urease were the highest in C₁₀₀F₅₀,while sucrase and acid phosphatase activity was highest in C₅₀F₁₀₀.In addition,the combined application of fungal residue and chemical fertilizer has obvious positive interaction effects on soil catalase,invertase,urease and acid phosphatase,and the effect of single application of fungal residue on each soil enzyme is better than chemical fertilizer.Except for sucrase,catalase,urease and acid phosphatase showed significant positive correlation（P<0.05）,and each soil enzyme had significant or extremely significant positive correlation with soil physicochemical factors（P<0.01）.（3）The combination of fungal residue and chemical fertilizer improved the richness and diversity of soil bacterial communities,while single application of fungal residues had a significant effect on the richness and diversity of soil fungal communities.From the analysis of the level of soil microbial community,Ascomycota and Proteobacteria are the dominant fungi of soil fungi and bacterial communities,respectively.From the analysis of the level of soil microbial communities,the fecal chlamydia and acidobacteriaceae are the best fungi for soil fungi and bacterial communities,respectively.From the analysis of the level of soil microbial community genera,Pleurotus ostreatus and Anaerobic genus are the dominant bacteria of soil fungi and bacterial communities,respectively.The correlation analysis showed that soil aromatic carbon,SOC（organic carbon）,AN and AK had significant correlations with fungal communities（P<0.05）;MBC,TP,TN,SOC,alkoxy carbon and carbonyl carbon had significant correlations with bacterial communities（P<0.05）.