Biochemical and crop responses of tea (Camellia sinensis) to applied nitrogen

Changes in nitrate-reductase enzyme activity in feeder roots and certain bi ochemical constituents of pluckable shoots in tea [Camellia sinensis (L.) O . Kuntze] after fertilizer application were monitored at weekly intervals i n the field-grown mature bushes to determine the optimum N level and the in terval between 2 applications. Nitrate-reductase activity (NRA) built linea rly up to 300 kg N/ha/year, but declined at 600 kg N/ha. Nitrogen at 600 kg /ha, though balanced with potash, inhibited NRA in feeder roots and increas ed the nitrogenous compounds in green shoots. The NRA was at peak during th ird week and declined in fourth week, For sustained efficiency and producti vity without any adverse effect on quality, 300 kg N/ha balanced with potas h applied at a minimum of 3-4 weeks interval appeared optimum.