Long-Term Fermented Chicken Manure (CM) Amendment Enhances Soil Health, Sugar Beet Yield, and Shifts Microbial Functional Diversity

Abstract

Organic fertilizers can provide economic and ecological benefits for nutrient management in soil–plant systems. However, the long-term effects of chicken manure application on rhizosphere microbial ecology and sugar beet yield remain unclear. Here, we conducted a six-year field experiment with CM application in a northern black soil area of China to analyze the long-term effects of CM on soil physicochemical and microbiological properties, as well as on sugar beet yield. Results indicated that long-term CM application increased sugar beet yield by 33.83%, soil organic matter (SOM) by 37.80%, and the soil quality index by 10.90% compared with no CM application. Continuous CM application also increased bacterial OTU richness and community diversity, enhanced predicted metabolic and membrane transport functions, and increased the complexity of bacterial co-occurrence networks in the rhizosphere soil. The use of CM also reduced the relative abundance of fungal taxa assigned as plant pathogens by 24.68%, but with a concomitant 4.35% increase in the relative abundance of rhizosphere fungal taxa assigned to animal pathogens in the rhizosphere fungi. In conclusion, long-term CM input enhanced the overall quality of black soil, optimized the sugar beet rhizosphere ecological environment, and mitigated surface source pollution from organic waste in animal husbandry. This study provides a basis for improving circular nutrient use, promoting on-site manure recycling, and supporting sustainable agricultural production.