Influence of nitrogen nutrition and watering regime on the nitrogen concentration and quality of tobacco leaves

Abstract

The effects of different levels of applied nitrogen, times of application of nitrogen and watering regimes on the nitrogen concentration of tobacco leaves, were studied in a series of glasshouse experiments. Time of nitrogen application was also studied in the field. Increasing the nitrogen supply increased dry weight and area of leaves but did not produce an increase in nitrogen concentration of leaves especially in the middle plant position. A significant increase in nitrogen concentration of leaves in the middle plant position was achieved by either split application of nitrogen or by imposing a regular watering stress during growth. The restricted watering treatment also reduced dry weight and area of leaves. Relatively high concentrations of nitrogen in the upper leaves resulted from late application of nitrogen and an experiment using labelled nitrogen confirmed that most late applied nitrogen was incorporated into upper leaves. Changes in leaf nitrogen concentration from time of removal of the inflorescence to final harvest are shown. A field experiment confirmed the glasshouse findings on time of nitrogen application and permitted cured leaf quality assessments to be made. Best leaf quality was produced by split application of nitrogen