Effects of different intercropping patterns on tea rhizosphere environment and leaf quality

Intercropping can improve tea soils and leaf quality, but partner-specific responses remain unclear. We compared four systems-Paris polyphylla-tea (CT), leguminous green manure-tea (LF), Pleurotus ostreatus-tea (CJ), and Polygonatum kingianum-tea (HJ)-with matched monoculture controls. Tea and soil traits were integrated with high-throughput sequencing, LEfSe, PICRUSt2 functional prediction, and correlation analyses. LF significantly increased soil available and total phosphorus, enriched the potentially beneficial fungi Mortierella and Trichoderma in the tea rhizosphere, and enhanced the predicted potential for microbial amino acid transformation, potentially facilitating leaf free amino acid accumulation, which increased by 28%. CT enriched Penicillium and enhanced predicted microbial carbohydrate-conversion and redox potential, potentially promoting leaf flavonoid accumulation, which increased by 21%. CJ significantly increased soil available phosphorus and potassium, enriched Talaromyces and Exophiala, and enhanced predicted organic-substrate-transformation potential, potentially facilitating organic matter turnover and nutrient release. HJ increased soil pH by 24%, enriched Nitrosomonadaceae and Rhizobiaceae, and enhanced predicted amino acid-, carbohydrate-, and phenylpropanoid-related metabolic potential, indicating improved acid-soil conditions and distinct microbial functional responses. Overall, different partners improved different attributes. LF showed the most balanced contribution to soil phosphorus status and amino-acid-associated tea quality, whereas CT, CJ, and HJ offered targeted advantages in flavonoid enrichment, phosphorus and potassium availability, and acid-soil amelioration, respectively. These findings support selecting intercropping partners according to specific soil-management and tea-quality objectives.