Soil drives humus formation during composition of wheat straw and cattle manure

Humus formation in compost is key to improving the quality of organic fertilizers. Soil has the potential to promote humus formation due to characteristics such as porousness and large amounts of nutrients, but the mechanisms by which soil drives humus formation are unknown. The study intended to reveal the effects of soil addition on humification and microbial metabolism during composting and to investigate the mechanisms by which soil drives humification. The results showed that hemicellulose and cellulose contents were reduced by 4.67, 11.8 % and 5.85, 6.26 % in compost with Paddy soil (PS) and Laterite soil (LS) addition, respectively, compared to control group. Humus and humic acid increased by 38.1, 38.8 % and 60.6, 77.8 % after composting. Soil addition significantly enriched the hydrolytic bacteria Corynebacterium and fungi Thermomyces , raising the efficiency of organic matter conversion and symbiotic metabolic network complexity. Soil addition improved carbohydrate and amino acid metabolism, facilitating polyphenol synthesis and amino acids polymerization, and enhanced the humus through the polyphenol humification pathway. In summary, by regulating the microbial metabolism during composting, soil can successfully encourage humus formation. This study offers a new option and method for quick humification.