Effects of Manure and Organic Fertilizer Application on Soil Microbial Community Diversity in Paddy Fields

To investigate the effect of typical manure application on soil microbes in paddy fields, a field experiment on manure application in Chongming Island was carried out. The composition and variety of soil microorganisms in rice paddy fields were analyzed using high-throughput theory (CK), chicken manure (CM), pig manure (PM), and organic fertilizer (OF). The results showed that compared with CK, the application of organic manure increased soil organic matter (SOM), and the application of chicken manure significantly increased the soil ammonia nitrogen (NH4+-N) and total nitrogen (TN) contents (P<0.05). Soil microbial diversity in the PM group was significantly higher than that in the CK group (P<0.05), and the soil microbial community richness in the OF group was significantly higher than that in the CM group (P<0.05). pH, total phosphorus (TP), total nitrogen, and Pb were the important factors affecting the composition of soil microbial communities in paddy fields. The microbial community structure in the CM group was significantly different from those in the other three groups. Compared with CK, the OF group increased the relative abundance of Nitrospira, and the CM group significantly reduced the relative abundance of the denitrifying bacteria Ignavibacteriae (P<0.01) to 40.56%, but significantly increased the relative abundance of nitrifying bacteria Thauera(P<0.05) to 203.00%. The PM group significantly increased the relative abundance of ammoniated bacteria Armatimonadetes (P<0.05) to 57.51% and the anaerobic strain Anaerolinea to 102.00%. The application of chicken manure and pig manure significantly increased the relative abundance of pathogens Pseudomonas and Flavisolibacter (P<0.05), respectively, while the application of organic manure reduced the relative abundance of Flavisolibacter. Overall, the application of manure increased the abundance of bacteria involved in the nitrogen cycle of paddy soils and played a positive role in regulating the nitrogen balance in paddy soils. However, direct application of chicken manure and fresh pig manure increased the abundance of pathogenic bacteria, which had a certain degree of stress on the soil health in the paddy field.