Effect of forms and levels of nitrogen [fertilizers] on the growth and accumulation of nitrogen, phosphorus, potassium and calcium by young tea plants (Camellia sinensis L.) grown in sand culture
1981
Krishnapillai, S. (Tea Research Inst. of Sri Lanka, Talawakelle)
The effect of four forms of nitrogenous fertilizers applied at five rates on the growth and uptake of NPK and Ca by young tea plants was studied. An increase in N supply usually improved growth up to a point beyond which it was not utilized in growth. Ammonium sulphate was exceptional in reducing growth as the supply increased and leaf symptoms presumed to be caused by ammonium toxicity were seen when this fertilizer was applied at the higher rates. The contents of NPK and Ca in the leaves were generally increased with increased supply of N as ammonium nitrate or urea. However, when nitrate was the sole source of N, the uptake of P was markedly reduced as the concentration of N was increased. Increased supply of Ca ions in the medium also resulted in reduced uptake of K
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