Effects Of Sulfur Fertilizer On Nutrients And Rhizosphere Microbial Communities In Maize Fields

In recent years,due to the decrease in the application of sulfur(S)fertilizers,S deficiency has appeared in the soil.Long-term application of S fertilizers can change the ecological environment of farmland soil and increase maize yields.Application of S fertilizers can change the content of soil nutrients and indirectly affect the community structure and function of soil microorganisms.Different types of S fertilizers(ammonium sulfate,sulfur)may affect the abundance and diversity of microorganisms involved in the soil S cycle.In order to explore the changes of microbial community structure in two soil types under different S application gradients and S fertilizer types,this study used black soil and sandy soil with different S application treatments as the research background,and maize rhizosphere soil samples were collected from field experiment under different application gradients and S fertilizer types,and 16 S r RNA high-throughput sequencing technology(Illumina Mi Seq)was using for the microbial community detection.The property of soil and the rhizosphere microbial bacterial community structure composition and diversity were studied.The results may explain the yield-improving effects of S fertilizer and instruct the farmers for S fertilizer rational application.The main research results of this paper are as follows:The pH of both soils showed a gradual decrease with the increase of S application rate.The content of soil AS(available sulfur)increased with the increase of S application,and reached the maximum in S150 treatment.Soil pH was lower when S element was applied compared to ammonium sulfate,but the AS content was higher.The content of available nitrogen(AN)decreased with the increase of S fertilizer application rate.The content of organic matter(OM),available potassium(AK),and available phosphorus(AP)were not significantly different between different treatment(P>0.05).Among different S application rate,the soil bacterial community abundance in black soil reached the maximum under S150 treatment,but in sandy soil the application of S fertilizer would reduce the soil bacterial community richness.In the two soil types,the soil bacterial diversity reached the maximum in S90 treatment,but there was no significant difference overall(P>0.05).The effect of ammonium sulfate application in black and sand soil were different.The application of sulphur increased the abundance and diversity of bacteria in black soils and the application of ammonium sulfate increased the abundance and diversity of bacteria in sandy soils.S fertilizer application had different effects on the relative abundance of maize rhizosphere soil bacterial communities in black and sandy soils.Among all treatments,Actinobacteria,Proteobacteria,Acidobacteria,Gemmatimonadetes and Chloroflexi was the dominant phylum(abundance>5%).The abundance of other phyla was lower.RDA analysis showed that soil pH,OM,AS,AN,AP,AK can all affect the community composition of maize rhizosphere bacteria,of which soil pH and AS were the main influencing factors.In the PLS-DA analysis result,the samples of different S fertilizer types were clearly separated,indicating that the S fertilizer type had a certain impact on the rhizosphere microbial community structure.And according to the ANOSIM analysis,the differences of rhizosphere microbial community between treatments were significant.The soil type has a significant influence on the microbial composition of the maize rhizosphere.The samples of black and sandy soils were displaced from each other in the PLS-DA result.And the number of taxa which were significant different between different treatments was higher in sandy soil,indicating that S fertilizer has a greater impact on the bacterial community structure in sandy soil.The PICRUSt was used to predict the function of maize rhizosphere soil bacterium under different S fertilizer treatment.A total of 6 first-level functions and 37 second-level functions were obtained,mainly involving the environmental information processing,genetic information processing,and metabolism.Among them,metabolism was the most important function,accounting for 52.6%-54.2%.The application of S fertilizer can increase the abundance of genes involved in S metabolism,however,when the S fertilizer application rate reaches 150,the abundance of genes related to S metabolism decreased.