Controlled-release fertilizer enhances soil nutrients and tea quality through microbial community modulation

Controlled-release fertilizer is an effective strategy for enhancing nutrient use efficiency and reducing environmental pollution. However, their impacts on soil properties and tea quality in different tea plantation soils remain unclear. In this study, we investigated the effect of slow-release diammonium phosphate fertilizer (SDAP) and controlled-release diammonium phosphate fertilizer (CDAP) on the soil nutrient and microbial community dynamics in newly reclaimed and replanted tea plantation soils. The results showed that CDAP fertilizer alleviated soil acidification and significantly increased soil available nitrogen and phosphorus availability, as well as organic matter content compared to SDAP in the two soils. The two fertilization methods distinctly influence the structure and composition of soil bacterial communities. CDAP enriched functional microorganisms, such as Proteobacteria and Actinobacteria are significantly associated with soil carbon and nitrogen cycling as well as disease suppression. In addition, CDAP increased the content of free amino acids and soluble sugars in tea leaves grown in replanted soils, likely through the increased abundances of Proteobacteria and Actinobacteria . These results suggest that controlled-release fertilizer improves soil physicochemical properties, shapes microbial communities and benefits tea quality.