As the global demand for high-quality tea increases, adopting sustainable agricultural practices is crucial to maintaining environmental health and improving crop productivity. Employing organic fertilizers has the potential to boost agricultural output and improve soil health, as well as curb the spread of pests and diseases. The purpose of this survey was to determine the impact of a range of organic fertilizer mixtures on both tea plants and rhizosphere soil characteristics in tea plantations. This study investigated the response of Jin Guanyin tea (Camellia sinensis L.) plants to various organic fertilizer ratios: 2/3 chemical fertilizer + 1/3 organic fertilizer (JTC), 1/2 chemical fertilizer + 1/2 organic fertilizer (JHOC), 1/3 chemical fertilizer + 2/3 organic fertilizer (JTO), and organic fertilizer only (JOF), with chemical fertilizer alone (JCF) as the control. The experiment was conducted in Xingcun Town, Wuyishan, Fujian Province, China, on 13 October 2021. Key metrics measured included tea plant growth indicators, soil physicochemical properties, enzyme activities, and microbial functional diversity. Results show that JTC and JTO produce the largest leaf area and bud weight, significantly surpassing those in JCF. JCF demonstrated the longest new tip length and highest bud density, while JHOC achieved the highest chlorophyll content, significantly exceeding JCF. Soil analysis revealed that total nitrogen, available nitrogen, organic matter, and pH were highest in JOF, significantly overtaking JCF. Conversely, total phosphorus, available potassium, and available phosphorus levels were highest in JCF. JHOC also had the highest total potassium content compared to JCF. Soil enzyme activity assessments showed that polyphenol oxidase and urease activities peaked in JTC, significantly exceeding those in JCF. JHOC exhibited the highest acid phosphatase activity, while JTO exhibited the highest protease activity. Catalase activity was highest in JOF, both significantly surpassing JCF. Microbial functional diversity analysis indicated that combined organic fertilization improved soil microorganisms’ utilization of carbon sources, significantly enhancing the Shannon diversity index and evenness. Key carbon sources identified included $\mathsf{\alpha }$-cyclodextrin, D-galacturonic acid, and 4-hydroxy benzoic acid. Overall, JHOC emerged as the optimal fertilization strategy, yielding superior growth indicators, enhanced soil physicochemical properties, increased enzyme activity, and improved microbial functional diversity compared to JCF. This study has important value for guiding the rational application of fertilizers in tea gardens, improving the soil environment of tea gardens, enhancing the quality of tea leaves, and achieving sustainable tea production.

This study systematically investigated the effects of stand age (5, 10, 20, and 40 years) on the biochemical components, mineral element accumulation in leaves, and rhizosphere soil properties of the tea shrub Camellia sinensis (L.) Kuntze cv. Wuyi Rougui. Analyses were performed on dried and ground leaf samples, and rhizosphere soil was collected from multiple independent plots per age group (n = 3). The results showed that the contents of tea polyphenols, water extract, caffeine, total flavonoids, and free amino acids in leaves initially increased, peaked at 10 or 20 years, and then decreased with increasing stand age. Soluble sugar content was highest at 5 years. The accumulation patterns of leaf mineral elements (Mg, Mn, K, Na, Fe, Zn, Cu, Ca) were also significantly influenced by stand age. Soil physicochemical properties (pH, total nitrogen, available phosphorus, organic matter, etc.) and enzyme activities (protease, polyphenol oxidase, urease, sucrase) exhibited distinct trends, i.e., pH decreased initially and then increased, while organic matter content increased with stand age. Principal component analysis (PCA) revealed that tea quality indicators, mineral elements, and soil properties clearly separated the 5- and 40-year groups, while the 10- and 20-year groups were closer. Pearson correlation analysis indicated significant positive correlations between leaf total flavonoids and soil ammonium nitrogen (r = 0.82, p < 0.01), and negative correlations between leaf soluble sugar and soil ammonium nitrogen (r = −0.75, p < 0.05). In summary, stand age was associated with systematic changes in both tea leaf composition and soil environment, suggesting that soil nutrient availability and enzyme activity may modulate tea quality formation. These findings provide a theoretical basis for age-specific soil and nutrient management in tea plantations.