2018 Volume 17 Issue 4 Pages 415-422
The effects of diurnal ventilation with a heat exchanger for dehumidifying were investigated to improve both the yield and quality of marketable tomato fruits grown in a greenhouse during winter. The heat exchanging ventilation based on the index of relative humidity lowered the temperature in the greenhouse. However, it ameliorated the inside conditions, such as decreasing humidity and reducing the period of dew condensation on the fruits. The concentration of carbon dioxide in the greenhouse remained higher than that of the control on cloudy days. Although the marketable yield from January to February decreased under the heat exchange ventilation, there was no significant difference in the total yield from January to May. In addition, the number of puffy fruits in March and April decreased, and total soluble solids from January to March were higher than those of tomato fruits cultivated in the control. Based on these results, it was revealed that tomato quality was improved compared with the control, while there was no significant difference in the total yield. Additionally it was suggested that the heat exchanging ventilation was effective as a dehumidifying technique for culture control.
