Optimization of the chicken manure to corn straw ratio and assessment of bacterial diversity during composting

Abstract

To enhance the quality of chicken manure and corn straw mixed compost, we evaluated the changes in physical, chemical indicators, and bacterial community diversity throughout the composting process. Three experimental groups were established with varying ratios of chicken manure to corn straw. The compost temperature was monitored daily, and samples were routinely collected to assess physical and chemical indicators. The results indicated that Group A (with a 6:4 ratio) entered the thermophilic phase earlier, sustained this phase for 20 days, exhibited faster organic matter degradation rates, and had a significantly higher total nutrient content by the end of composting compared to the other groups. The 16S rRNA high-throughput sequencing technology was utilized to investigate the alterations and distinctions in the bacterial community across 5 sampling layers of Group A samples on days 5, 15, 25 and 45. It was found that the diversity of bacterial communities initially increased, then decreased, followed by a slow increase and eventually stabilized. The predominant bacterial phyla during composting were Firmicutes , followed by Actinobacteria and Proteobacteria. The distribution ratio of bacteria in each sampling layer at each stage was small, while the main bacterial genera included Bacillus , Corynebacterium , Tepidimicrobium , Halocella , Planifilum , Luteimonas , and Actinomadura . Linear discriminant analysis revealed that the bacterial community with the greatest impact on organic matter degradation was the genus Bacillus ( Firmicutes ).