Greenhouse cultivation feasibility using condensation irrigation (studied plant: Basil)

Abstract

Solar desalination is one of the techniques to overcome the water scarcity in agriculture sector in the areas having saline water. Condensation Irrigation is a combination of subsurface irrigation and solar water distillation. In this study, a condensation irrigation was developed in a greenhouse. A reservoir (humidifier) was constructed in which saline water evaporated using an electric heating element. The water vapor warmed and humidified the airflow above the saline water surface and this humid air was blown into a series of perforated pipes with the length of 2 m buried in the planting medium. The vapor of humid air condensed on pipe walls and planting medium and supplied water requirement of basil plants. The experiments were carried out without (first experiment) and with plastic coating on the planting medium (second experiment). The measurements showed that dry matter production in the first and second experiments were, respectively, 63% and 286% higher than that of the conventional irrigation. Furthermore, the water vapor was transmitted by humidifier to the perforated pipes with the rate of 12.5 lit/day, of which, 33.2% in the first experiment and 50.8% in the second experiment was condensed in the planting medium and pipes. Accordingly, the average irrigation rate in the first and second experiments was 2.08 and 3.18 mm/day, respectively. The average temperatures of the planting medium in the first and second experiments were 34.1 and 34.8 °C, respectively. It was concluded that condensation irrigation was able to meet the basil water requirement in greenhouse cultivation and the temperature due to condensation did not limit the plant growth.