PEffects of location of production, nitrogenous fertilizer rates and plucking intervals on tea clone TRFK 6/8 tea in East AFRICA: II. Mature leaf nutrients

Abstract

Due to high demand for tea beverages, Camellia sinensis is grown under diverse climatic conditions. The demand has led to development of high yielding clones which require high nutrients amounts usually lost through continuous cropping, leaching and surface runoff due to which it is very important to replenish these nutrients through the application of fertilizers. Tissue analysis is the reliable way to predict nutritional status leading to time migitation through supplementation of nutrients through fertilizer. To guide fertilizer requirements in East Africa, first mature leaf tj^pe analysis is done and the same analysis was adopted for clonal tea. It is not known, the standard set for the seedling tea are relevant for clonal tea and how the levels are influenced by nitrogen fertilizer rates or plucking intervals in different locations. This study assessed effects of location of production, nitrogen rates and plucking intervals on mature leaf nutrients of clone TRFK 6/8, the most widely cultivated cultivar in East Africa. The trials were set up in Kenya, Tanzania and Rwanda, as factorial two in randomized complete block design at each site. Leaf N, P, K, Ca, Mg, Mn, Zn, Cu and Fe were determined using standard methods. All nutrients significantly (P less than 0.05) varied with locations. At all locations leaf N increased (P less than 0.05) while K, Mg and Ca declined (P less than 0.05) with increase in nitrogen rates. Plucking intervals did not influence leaf nutrient levels. The nutrients levels did not match those set for seedling tea even when nutrients were supplied adequately. Diagnostic limits set for seedling tea may therefore not be suitable for clone TRFK 6/8, hence there is need to develop region specific tissue analysis diagnostic norms for clonal tea. The responses to applied nitrogen demonstrate that nitrogen deficiency can be managed through nitrogen fertiliser application. However, such applications trigger decline in potassium levels in the leaf The applications of the two nutrients should be staggered to increase their uptake efficiency. Continuous application of high rates of nitrogenous fertilisers could cause deficiency of K, Ca, and Mg while causing toxicity of Mn.