EFFECT OF NATURAL VENTILATION ON PRODUCTIVITY AND FRUIT QUALITY OF CUCUMBER FRUIT GROWN UNDER PLASTIC HOUSE

Abstract

This study was conducted at El-Bosaily Protected Cultivation greenhouses (Agricultural Research Center) during 1998 and 1999 seasons in order to study the possibility for improving natural ventilation of existing single arch plastic houses. Cucumber ( Cucumis sativus L.) cv. Primo F 1 seedlings were transplanted to the plastic house during February in both seasons. Two methods of natural ventilation were tested in comparison with a standard plastic house that contains 1.8 m2 maximum ventilation opening in the overlap area, every 5m longitudinally ( 12.6 m2 I 360 n/ cultivation area). The first tested method was the side ventilation of one meter width along both sides of the plastic house (80m 2 opening/360m2 cultivation area) and the second tested method was a longitudinal top ventilation of about 0.8 m (32 m2 opening/360m 2 cultivation area). The res_ults showed that side-ventilation reduced greenhouse air temperature about 4-5 °C in summer season compared to control. Relative humidity was lower in the side-ventilation treatment followed by top-ventilation then the control. Using side-ventilation increased plant height, number of leaves and total leaf area. These were re1lected positively on the early, total and marketable yield where the highest early and total yield were obtained by using side­ ventilation followed by top-ventilation comparing with control.

Key words: Side ventilation- Top ventilation -Humidity­ Temperature.