Effect of fertilizer levels and plucking intervals on yield and quality of clonal tea [Camellia sinensis (L.) Kuntze]

Variation in yield and black tea [Camellia sinensis (L.) Kuntze] quality of a high-yielding clone, S 15/10 in response to rates of NPKS 25:5:5:5 (at 100-600 kg N ha(-1) yr(-1)) fertilizer and three plucking Intervals (7, 14, and 21 days) were studied. Yields responses were quadratic, reaching calculated maximum production when 466, 487, and 491 kg N ha(-1) yr(-1) was applied at 7, 14, and 21 days plucking intervals, respectively. But significant yield increase was achieved by applying only up to 200 kg N ha(-1) yr(-1). The most profitable production was also achieved by applying 200 kg N ha(-1) yr(-1) irrespective of plucking intervals, at the 1993 production costs in Kenya. Mean weights of plucked (two leaves and a bud) shoots, shoot density, and shoot extension rate increased with fertilizer rates. On unselective plucking, long plucking intervals produced leaf with a high proportion of mature (coarse) leaf beyond two leaves and a bud.