Nitrate Reductase Activity in Tea as Influenced by Various Levels of Nitrogen and Potassium Fertilizers

Abstract

Leaf and root samples were collected from experimental blocks treated with different levels of nitrogen and potassium (NK) and analyzed for nitrate reductase (NR) activity. It was inferred that in a tea shoot consisting of three leaves and a bud, the NR activity was higher in first leaf followed by third leaf and feeder roots. Increase in NR activity was noted due to the increase in N or K fertilizer doses. There existed a significant correlation between green leaf yield and NR activity recorded at first and second harvesting rounds after manuring. Activity observed at the Anamallais was slightly higher than that seen in the Nilgiris. The activity was maximum on the seventh day after fertilizer application and it was considerably high up to 28th day, which revealed that the minimum interval between two successive NK fertilizer applications should be one month. The N:K2O ratio 1:1 appears to be optimum when 300/450 kg of N as urea (or) K2O as muriate of potash ha−1 yr−1 was used.