[Effects of Cow Manure Application on Soil Microbial Community in Farmland]

Although livestock manure serves as an effective source of nutrients for agricultural purposes, it also causes an obvious risk of contamination of heavy metals and pathogens in soil. Soil microorganisms are always considered a sensitive indicator for the change in soil quality. However, knowledge of the effects of cow manure application on soil microbial community is still scarce. Therefore, the characteristics of the soil microbial community and its influencing factors in the farmland with cow manure application were studied using dilution plate counting and high-throughput sequencing. The results showed that the β diversity of the soil microbial community exhibited a significant difference between the cow manure application site and control site. The application of cow manure increased the relative abundance of Proteobacteria but decreased the relative abundances of Actinobacteria and Gemmatimonadetes. Furthermore, the cow manure application significantly changed the relative abundances of Sphingomonas,PLTA13, MSB-4B10, Halomonas, CCD24, Gaiella, Arthrobacter, Bacillus, and Entotheonellaceae. Both the content of soil water and actinomycete numbers were the important influencing factors of soil microbial community composition in the farmland with cow manure application. The cow manure application increased the relative abundance of pathogenic bacteria including Pseudomonas, Clostridium, and Streptococcus, which may have resulted in potential risks of pathogenic contamination for soil quality. The findings of this study are useful for understanding the effects of cow manure application on soil quality in farmland.