Response of Nutritional Status and Tea Quality to the Rate and Substitution of Chemical Fertilizers with Organic Manure

Proper fertilization is important to sustainable tea production. A field experiment was conducted to investigate the response of quality components in a chlorotic tea variety (Zhonghuang-2) to rates of fertilizers and the substitution ratio of chemical fertilizers by organic manure based on rapeseed cake. Chlorotic tea varieties have unique metabolic characteristics and produce superior tea containing high contents of free amino acids. Results showed that fertilization significantly increased yield and contents of free amino acid (TFAA) but reduced contents of total polyphenol (TP) and the ratio of TP/TFAA. Contents of TFAA and TP and the TP/TFAA ratio were closely related to nitrogen (N) concentrations in plant tissues in response to the rate of N fertilizers. The results suggest that the quality-related components in the chlorotic tea variety respond to fertilizers in a similar way as normal tea varieties. The optimal rates of N, phosphorus (P), and potassium fertilizers were discussed and recommended based on the response of quality components of tea and the contents of nutrients in plants and soil. The full substitution of chemical fertilizers by organic manure showed no special benefit on tea quality and had lower N and P agronomic use efficiency due to a low bioavailability of nutrients. The partial substitution of chemical fertilizers by organic manure significantly improved tea yield, quality, profit, and economic and environmental sustainability.