Nitrogen and Potassium Dynamics in Tea Cultivation as Influenced by Fertilizer Type and Application Rates

Abstract

As the most important cultural practices for tea production, single effects of nitrogen (N) and potassium (K) fertilization on yield are well documented but their dynamics are poorly understood. It was necessary therefore to assess the dy-namics of nitrogen and potassium in tea cultivation environment as influenced by fertilizer application rates. This ob-jective led to a comprehensive field investigation in strongly acidic soils tea plots at Tea Research Foundation of Kenya, Kangaita substation in Kerugoya using clone TRFK 11-4 in a 3 × 3, N × K factorial RCB design. Treatments were ni-trogen (0, 100 and 200 Kg N·ha −1 ·yr. −1) as urea and potassium (0, 40 and 80 Kg K 2 O ha −1 ·yr. −1) as Muriate of potash (MoP) replicated thrice. Tea yield, plant biomass and plant nutrient concentrations were measured for calculation of plant nutrient uptake. Nutrients accumulated in the plants and removed from harvest were considered as nutrient loss, while fertilizer was considered as nutrient inputs gain to soil. In the interaction, there was no much difference between N-K treatments and crop N removal except mature and maintenance leaves, but there was a positive linear relationship between N applied and the yield of made tea and negative linear relationship between K applied and yield of made tea. The results from the study also showed that fertilizer inputs generally surpassed the crop nutrient demands (nutrient loss from harvest).