Effects of reducing chemical fertilizer on the quality components of Tieguanyin tea leaves

Abstract

Fertilizer plays an important role in agricultural development. However, the soil environment of tea gardens has been deteriorated and the growth of tea trees has been hindered by the long-term excessive chemical fertilizer used in tea gardens. To study effects of reducing chemical fertilizer on the quality components of Tieguanyin tea leaves, Tieguanyin tea garden located in yellow-red soil was treated with three consecutive times and five recipes of chemical fertilizer. The results showed that appropriate reduction of chemical fertilizer applied in tea gardens can increase the contents of potassium and organic matter in soil, polyphenols and water extract in tea leaves. Most of the contents reach their peaks in T3 treatment, which compound fertilizer that the contents of NPK are all 15% was 412.50 kg/ha and urea was 206.25 kg/ha applied in the tea gardens, that 55% of the conventional usage by local farmers. At the same time, with the reducing chemical fertilizer applied in tea gardens, the caffeine in tea leaves was significantly decreased. Therefore, T3 treatment can improve the soil environment of tea gardens and the concentration of Oolong tea soup. Besides, it infers that the amount of chemical fertilizer in T3 treatment is a key control point for the quality of tea. The indirect influence coefficients that the chemical fertilizer effects on the contents of tea water extract, free amino acid and caffeine are all at their peaks of 5.249, 4.245 and 8.594 respectively through the changing of the soil nutrient contents. It is benefit for improving the overall quality of Oolong tea.