Response of soil micro-food webs to the addition of maize straw and animal manure in a mollisol

The soil micro-food webs play vital roles in the decomposition of soil organic matter, and thus in the quality and sustainability of cropland ecosystems. However, responses of soil micro-food webs to the addition of maize straw and animal manure in a mollisol remain unclear. Four treatments were examined: no maize straw and no animal manure control (CK); maize straw only (MS); chicken manure plus maize straw (CS); ox manure plus maize straw (OS). The results showed that soil microbial phospholipid fatty acids (PLFAs) and the abundance of total nematodes both increased in the organic waste treatments compared with CK. Additionally, treatment CS increased the bacterial PLFAs and bacterivore abundance. The bacterial biomass carbon in the CS-treated soil was 67.8–81.2% higher than that in the CK treatment. Treatment OS showed a significantly positive correlation among fungi, fungivores and predator-omnivores. The findings indicated that CS activated the decomposition pathway between bacteria and bacteriovores, while OS activated the decomposition pathway between fungi and fungivores. Consequently, the addition of animal manure and maize straw improved soil carbon accumulation and enhanced the stability of soil micro-food webs.