Response of young tea [Camellia sinensis] plant to nitrogen application in relation to growth, photosynthesis and total nitrogen in new shoots.
1995
Okano K. | Matsuo K. | Chutani K.
Response of two-years-old tea (Camellia sinensis L.) plants to various amount of nitrogen application was analyzed in order to clarify the optimum level of nitrogen nutrition in terms of growth, photosynthesis and nitrogen content in new shoots. Plants were grown in a pot containing 3.5 litre of soil under the condition of glasshouse. Defining an arbitrary unit of nitrogen application as 1 N plot, eight experimental plots (ON-12N) were prepared. As a nitrogen source, ammonium sulphate was applied to the pot with five splits in a year. Nitrogen absorption by a plant increased in proportion to the rise of application level up to 4 N plot, above which little increase was observed. As a result, recovery rate of applied nitrogen by the plant decreased exponentially with the rise of application level. Growth of whole plant and photosynthesis of mature leaves also increased with the rise of application level up to 4 N plot, above which no further increase was detected. No significant effect of nitrogen was observed on the respiratory rate of roots among the nitrogen application level. Meanwhile, growth of first flush shoots and total nitrogen content in the shoots increased with the rise of application level up to 8 N plot. These results indicated that the optimum level of nitrogen for the quality of new shoots was greater than that for the growth or physiological functions of tea plants. This might be one of reasons which brought about the tendency to the excess input of nitrogen fertilizer to the tea field. In the present experiment, any injury of the tea plants caused by excess nitrogen could not be detected.
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