The Effect Of Reducing Application Of Bio-organic Fertilizer Instead Of Chemical Fertilizer On Soybean Soil Microbial Diversity

The blind and excessive application of chemical fertilizers leads to a decrease in soil organic matter content and soil acidification,which poses a serious threat to the sustainable development of current agriculture.As a new type of green fertilizer,bio-organic fertilizer can effectively improve soil fertility and increase crop yield,and it also has a certain inhibitory effect on crop diseases and insect pests.As a valuable soil resource,the northeast black soil directly determines the grain yield of China.This paper aims to systematically study the effects of bio-organic fertilizers instead of chemical fertilizers on soil physical and chemical properties,soil enzyme activities and soil microbial diversity,and explore the northeast black soil fertility to improve the sustainable development of agriculture through correlation analysis of various indicators.The main research results are as follows:Bio-organic fertilizer instead of chemical fertilizer reduction technology significantly reduced soil available potassium content,and other physical and chemical indicators were improved.Especially in the pod-forming period,the organic matter content was significantly increased by 23.33% compared with the FJCK treatment group;the total potassium content of the FJT2 treatment group was significantly increased by 4.33~6.34% compared with the FJCK treatment group;the available potassium content of the FJT2 treatment group was significantly lower than that of the FJCK treatment group.13.75~32.82%.The partial replacement of chemical fertilizers by bio-organic fertilizers and the incremental application of chemical fertilizers showed a significant decrease in soil sucrase,urease and phosphatase activities: the partial replacement of chemical fertilizers by bio-organic fertilizers was significantly reduced by 15.14~25.36%,4.65~8.86% and 16.31~22.28%,respectively.In addition,the fertilizer treatment methods were significantly reduced by 0.3~29.91%,9.6~17.44% and 16.59~30.46%,respectively.The replacement of chemical fertilizer by bio-organic fertilizer has certain influence on the composition of soil bacterial community.Proteobacteria,acid bacillus,actinomycetes and chloroflexi are dominant bacteria,and the relative abundance of proteobacteria in FJT2 treatment group is significant.Compared with other treatment groups,proteobacteria generally grow in a nutrient-rich environment,indicating that the application of bio-organic fertilizer increases soil nutrient content;redundancy analysis(RDA)indicates that soil bacterial community structure is significantly correlated with part of soil physical and chemical properties,such as the effects of available potassium(AK),available phosphorus(AP),alkaline nitrogen(AN)and phosphatase showed that the effect of bio-organic fertilizer instead of chemical fertilizer on soil bacterial community structure was indirectly affected by the change of physical and chemical properties.In addition,the relative abundance of bacillus species with relatively low abundance showed a significant increase with the application of fertilizer,indicating that the application of fertilizer has a certain promoting effect on the growth and development of crops.The replacement of some chemical fertilizers by bio-organic fertilizers affected the composition of soil fungal communities,significantly increased the relative abundance of the genus gibberella,and reduced the relative abundance of fusarium,indicating that bio-organic fertilizer or bio-organic fertilizer partially replaced fertilizers that can effectively inhibit the occurrence of crop diseases.Redundancy analysis(RDA)showed that soil bacterial community structure was significantly correlated with some soil physical and chemical properties,such as total potassium(TK),alkali nitrogen(AN)and invertase activity,indicating that the effect of biological fertilizer instead of chemical fertilizer on soil bacterial community structure is indirectly affected by the change of physical and chemical properties.In summary,the partial replacement of chemical fertilizers by bio-organic fertilizers and bio-organic fertilizers has improved soil physical and chemical properties and soil enzyme activities;the soil microbial community structure has been changed through changes in soil physical and chemical properties.Furthermore,the replacement of chemical fertilizers by bio-organic fertilizers has significantly increased soybean yield by 16.88%.