Effects Of Partial Substitution Of Organic Fertilizers On Soil Nutrients And Biological Activity In Apple Orchard

The content of soil organic matter in apple orchard in China is much lower than that in Europe and America,and many studies show that soil organic matter,soil enzyme activity,soil microbial community and its diversity are important index of soil fertility.Application of organic manure in orchard can not only improve soil organic matter and soil quality,It can also change the community structure and composition of soil microorganisms.In this study,four fertilization treatments were set up in the apple orchard:1)CK,chemical fertilizer N,2)OFN20%,organic N substituting 20%of chemical fertilizer N,3)OFN30%,organic N substituting 30%of chemical fertilizer N,4)OFN40%,organic N substituting 40%of chemical fertilizer N.The effects of applying organic manure on soil chemical fertility,the soil biological fertility and soil microbial flora in apple orchard were studied.The main findings are as follows:1.The application of organic manure enhances the content of organic matter in soil,enhances the content of available nutrients in soil,and helps to improve soil fertility.Compared with CK,the content of soil organic matter in OFN20%,OFN30%and OFN40%increased by 2.15%,5.47%and 7.64%respectively.Compared with CK,the content of soil available phosphorus in OFN20%,OFN30%and OFN40%increased by 20.92%,23.46%and 26%respectively.Compared with CK,the soil available potassium content of OFN20%,OFN30%and OFN40%increased by 14.05%,21.46%and 29.25%respectively.Compared with CK,the soil NO3-N content of OFN20%,OFN30%and OFN40%increased by 24.14%,28.49%and 37.66%respectively.2.Applying organic manure can increase soil enzyme activity and improve soil quality.Compared with CK treatment,organic manure treatment significantly increased the activity of ?-glucoside,invertase,beta-glucoside,beta-glucoside,beta-cellulose,catalase,urease and phosphatase.3.The improvement of microbial community structure and diversity in soil is the foundation of soil ecosystem stability in apple orchard.Compared with CK,organic manure treatment significantly increased the abundance of 16S rRNA gene and 18S rRNA gene in soil,increased the richness index and diversity index of bacteria and fungi,and significantly changed the community structure of bacteria and fungi.Organic manure treatment increased eutrophic bacteria taxa(copiotroph)such as the Arabidopsis gate,the relative abundance of alpha-and gamma-proteobacteria and reduced the relative abundance of oligotrophic bacteria(OLIGOTROPH),such as Lactobacillus,and increased the beneficial microbial groups such as Xanthomonas and Bacillus.The relative abundance of organic carbon and nitrogen-fixing microbes Rhodospirillales,and Ascomycota and ilyonectria were also increased.Conclusion:The application of organic manure enhances the content of organic matter and total nutrients in soil,enhances soil pH and soil enzyme activity,changes the community structure of soil microorganisms,and increases the abundance of nutrient-rich taxa and beneficial microorganisms in soil.Therefore,applying organic manure can improve soil fertility,improve soil quality and build stable soil ecosystem.