Abstract
The present experiment was undertaken in order to clarify the effect of application of ammonium nitrogen to the nutrient solution on the growth, yield, photosynthesis, chlorophyll content and root activity of pepper plant (Capsicum annuum L.) at day temperatures of 25, 30 and 35°C.
Cultivar‘Nokkwang’ used in this experiment showed the highest growth and yield at 30°C, indicating that the optimum day temperature should be controlled at this level.
At the day temperatures of 25 and 30°C, NH4-N application at the ratio of 20% against total applied nitrogen resulted in the stable acidity of the solution. Further beneficial effects of NH4-N application resulted in higher fresh weights of leaf and stem, increases in leaf area and root respiration, as well as higher fruit number and yield. Chlorophyll content in the leaf increased with NH4-N application at all day temperature.
At the day temperature of 35°C, however, NH4-N application resulted in decreased plant growth and yield. Results obtained indicate that the plant grown in summer at high temperature should be applied with NH4-N free solution, and that NH4-N should be applied in order to encourage the plant growth and yield in the other seasons.
