Soil Fertility and Bacterial Community Composition in Response to the Composting of Biochar-Amended Chicken Manure

Abstract

Amidst the burgeoning expanse of the poultry sector, the escalation of chicken manure production has ensued, potentially exacerbating ecological contamination. However, the application of chicken manure is bound to transmute the habitat of edaphic microorganisms, precipitating an alteration in the soil’s microbial consortium. The composting of biochar-amended chicken manure and wood chips (biochar composting products, BCPs) was used to improve Chinese cabbage (Brassica campestris L.) production and regulate soil properties and bacterial community structure. On the 40th day of Chinese cabbage growth, soil and Chinese cabbage were collected for laboratory analysis. The effects of different proportions of BCPs (0, 1%, 3%, 5% and 7% biochar) on soil fertility, enzyme activity, the microbial community and the growth of Chinese cabbage were studied under facility conditions. The results showed that the growth performance and quality of Chinese cabbage were significantly increased with increasing BCP ratios. Soil fertility indicators including pH, AN, AP, AK and SOM were significantly increased, except for the pH value in the 1% BCP group. The activities of phosphatase, catalase and urease were increased for all groups of BCP treatment. The soil microbial community response was significantly different, and the application of 5% and 7% BCPs reduced the abundance, diversity and evenness of soil bacteria. Chinese cabbage growth performance was positively correlated with an increase in BCP supplemental levels in the range of 3–5%. Also, the abundance, diversity and uniformity of the soil microbial community were improved in the 3% BCP treatment group. Therefore, the dominant bacterial phyla were Bacteroidetes, Actinobacteriota, Gemmatimonadota, Myxococcota, Bdellovibrionota and Firmicutes, especially the Bradyrhizobium of Proteobacteria. BCP treatment reduced the degradation of soil organic matter. In addition, it also improved the relative abundance of sequences associated with improving soil fertility. Collectively, these findings offer insights for the re-evaluation of application management strategies for BCP organic fertilizers.