Partial substitution of nitrogen fertilizers by organic products of rural waste co-composting impacts on farmland soil quality

Substituting nitrogen fertilizers with organic fertilizer is considered as an important measure to address agricultural non-point source pollution. However, little is known about the impact on soil environment of rural multi-source waste compost products to substitute nitrogen fertilizers. Here we examined the response of soil quality to the alternative application of organic products which previously made from co-compost of swine manure, human excrement and rice straw. According to the soil quality evaluation model, we observed that compost product application improved soil quality, wherein 40% compost product instead of nitrogen fertilizer showed a best effect on promoting soil quality. This was strongly related to microbial diversity and their network complexity. Also, compost product application shifted the composition of bacterial and fungal communities, significantly increasing relative abundances of dominant bacteria phyla (e.g. Proteobacteria, Actinobacteriota and Gemmatimonadota) and fungal phyla (e.g. Ascomycota), which indicated that compost product application facilitate the growth of microorganisms eutrophic taxa of microorganisms. Collectively, this study gives an optimal solution to replace nitrogen fertilizers by co-composted organic product and provides a deeper understanding of the impact of rural waste co-composted product on agricultural soils along with their value for agricultural utilization.