Abstract: To effectively address the issue of sludge cake resource utilization, we conducted pot experiment to investigate the effects of bacterial residue-modified sludge cake on the growth of ryegrass as well as the structure and abundance of the microbial community in soil roots. The results revealed that bacterial residue significantly enhanced the nutrient content, such as hydrolyzed nitrogen, available phosphorus, available potassium, in the soil. Bacterial residues also exerted a notable impact on plant growth (P<0.05), leading to a remarkable increase in root length by up to 3.3%. Meanwhile, bacterial residues changed the microbial community structure of soil roots, with a significant increase in the relative abundance of Actinobacteriota. These findings further validate the feasibility of developing and utilizing sludge cake modified with bacterial residues, offering a novel approach for the resource utilization of sludge cakes.

Key words: sludge cake improvement, bacterial residue, ryegrass, diversity, relative abundance