Effects Of Long-Term Different Fertilization On Microbial Diversity And Functional Microflora In Corn Rhizosphere

As an important part of the farmland ecosystem,soil microorganisms play an important role in the development of soil fertility and the stability of the ecosystem.The population structure and functional diversity of microorganisms in soil are affected by factors such as land use,cultivation,and fertilization.Fertilization is one of the key influencing factors.However,the effects of Long-term different fertilization on soil microbial community structure and nutrient cycling function genes have drawn much attention in recent years,but the potential relationship between them is not yet clear.Therefore,in order to define the changing rules and their relationship of soil microorganisms under different fertilizations,we baced on the different fertilization treatment of corn rhizosphere soil as the research object in the platform of long-term positioning test field.Through routine analysis,modern molecular biology research methods such as 16Sr DNA and ITS rDNA high-throughput sequencing technology of Illumina MiSeq platform and real-time PCR technology are evidenced,Through the analysis of corn yield,corn rhizosphere soil nutrients,diversity of fungal communities,bacterial community diversity and carbon or nitrogen cycling and phosphate?solubilizing bacteria functional flora abundance of different fertilization treatment,discuss the correlation between fertilization?soil nutrient?corn yield and soil bacterial fungi abundance?functional flora abundance,It is intended to explain the differences in the structure and composition of soil microbial communities and the differences in abundance of nutrient cycling genes under long-term black soil fertilization in Northeast China.It is expected to provide a theoretical basis for building a good soil ecological environment.The main results are as follows:?1?Long-term different fertilization has a significant impact on soil nutrients,fertilizer application increased soil organic matter?SOM?and total nitrogen?T-N?content,especially the treatment of adding corn straws,However,the differences of soil moisture?MC?,total phosphorus and total potassium?T-P,T-K?between different treatments were not significant.Long-term application of nitrogen fertilizer significantly decreased soil pH and acidified the soil,but increased the bulk density of corn,100-grain weight of maize and maize yield?P<0.05?,and increased the yield by 63.23%,so we can think of the nitrogen fertilizer as an important factor affecting the cron yield.?2?Long-term fertilization significantly reduced soil fungal abundance and uniformity,In all fertilization treatments,the phytopathogenic fungi at the gate level had similar abundance of species,included Ascomycota,Basidiomycota,Zygomycota,Glomeromycota and Chytridiomycota,but there was a significant difference in species abundance at each level under the fertilization treatment.In the treatment of NPK with high amount of straw?NPK+S0.5?,Ascomycota reached 70.35%.Humicola,Fusarium,Verticillium and Mortierella are the dominant bacteria,and belong to the same cluster with one branch of the 109 known genus leval of fungi.Diversity index and Heatmap analysis shows that the application of nitrogen fertilizer to make fungal community composition there is a significant difference.In the RDA analysis,the soil pH,total nitrogen,phosphorus and potassium?T-N,T-P,T-K?,available phosphorus and potassium?A-P and A-K?and ammonium nitrogen?NH₄⁺-N?were the important environments that affected the community structure of soil fungi factor.?3?The soil bacteria sequencing analysis showed that 8621 OUT sequences were detected?at 97%similarity?,there was a correlation between OTU abundance and soil pH?P<0.05?.The highest abundance Phylum level of bacteria was Acidobacteria,accounting for 33.2%of the total,followed by Proteobacteria,Bacteroidetes,Firmicutes and Actinobacteria,There are obvious differences between different treatments,the abundance of Acidobacteria of treated with nitrogen fertilizer was significantly lower than that without nitrogen fertilizer.Among the 329bacterial genus detected,Acidobacteria-Gp6,Gp4 and Alistipes were dominant bacteria.Diversity index and NMDS analysis showed that adding nitrogenous fertilizer could increase the bacterial community diversity.In the RDA analysis,the highest correlation between soil pH and bacterial community composition,and soil organic carbon?TOC?and soil total nitrogen?T-N?also had a higher correlation with bacterial community composition?P<0.05?.?4?There were some differences in abundance of functional genes in soil microbes under different long-term fertilization treatments,The AOA abundance of long-term application of straw fertilization was significantly less than that of no straw addition?P<0.05?,The AOB abundance of long-term non-nitrogen fertilizer treatment was less than that of nitrogenous fertilizer treatment?P<0.05?,and the nifH abundance have no significant difference in non-nitrogen fertilizer?P>0.05?,The nosZ abundance in the treatment of adding high amount of straw was lower than that of adding low amount of straw,there were negatively correlated between AOA and nosZ with soil TOC and TN?P<0.05?.The cbbL abundance have no significant difference in all the treatments,but no addition of straw was less than that of straw addition,and there was a significant positive correlation between cbbL gene abundance and soil pH and TOC?P<0.05?.The abundance of phosphate solubilizing function gene Gdh3 was less than that without phosphate addition,and the abundance of Gdh3 functional gene was positively correlated with soil A-P and T-P?P<0.05?.