Effect of sludge compost on soil N mineralization and microbial community of tree peony

Composted sewage sludge has a potential to substitute inorganic fertilizers. A greenhouse experiment was conducted to investigate the impact of sewage sludge compost application on soil N mineralization and nitrification, and substrate utilization pattern of microbial communities under tree peony (Paeonia suffruticosa). The sludge compost application of 15-75% significantly increased soil N mineralization rate and nitrification rate compared to the control (no amendment), with the maximum at compost application dosage of 45%. The average well color development based on the carbon source utilization pattern in Biolog EcoPlates significantly increased from sludge compost application of 0 to 45%, and then a decreasing trend was observed for compost application dosage higher than 45%. The principal component analysis of carbon utilization pattern showed that the change trends of the scores on the first principal component with increasing sludge compost application dosage were different before and after 45%.