Foliar absorption of 15N labeled urea by tea plant

The effect of foliar application on the nitrogen nutrient status of tea shoots has been studied using 15N labelled urea. Furthermore, the difference in nitrogen utilization by tea plant between foliar applied and top dressed nitrogen was investigated using 15N labelled urea and ammonium sulfate. The foliar application of urea increased the amount of chlorophyll and total nitrogen in the new shoot, and the foliar application was more effective under shading condition. The urea sprayed upon old leaves prior to the opening of new leaf translocated to the new shoots. However, the foliar application after the opening of new leaf was more effective on nitrogen absorption by new shoots than one prior to that, and rather than top dressing for new shoots. It could be recognized that the foliar application of urea raises the nitrogen nutrient status of tea leaves in summer. (author)