Objective Effects of various fertilizers containing water-soluble ingredients on the growth and quality of tea plants were evaluated to optimize the fertilization practice at plantations.

Method In a field experiment without trenching, along with no fertilization as control (CK), a nitrogen fertilizer (T1), a water-soluble fertilizer (T2), or a compound fertilizer (T3) was applied on the lots for topdressing to compare the growth and quality of tea bushes.

Results  In comparison with CK, all the fertilization treatments increased the shoot length, distance between leaves, moisture content, and biomass of the tea plants over CK. T1 was more effective in promoting growth than T3, which included phosphorus and potassium, as the biomass of the T1-treated plants was increased by 150%, but those of the T3-treated counterparts by 130% and the T2-treated ones by 120%. The free amino acid content was significantly higher in the plants treated by T3 with a 15% more than in those treated by T1. However, the water solubility of the added phosphorus and potassium in T3 did not significantly affect the amino acid content. On the other hand, the fresh leaves of the plants grown under T2 had significantly 15-20% more free amino acids than those under T1 and 5-7% more chlorophyll under T3. T2 also produced brewed tea with improved color but not significantly differed from T1 on the polyphenol content, phenol to ammonia ratio, and anthocyanin index of the shoots.

Conclusion On the plantation field without trenching, the water-soluble fertilizer (T2) amply supplied the essential nutrients needed for an efficient growth of the tea plants. Its application also significantly improved tea quality over the other fertilizers.