Environmental patterns under rain shelter for strategic environmental control in a tropical greenhouse

I. Mat Sharif, C.H. Mohammud and M.K. Illias

Abstract

The benefits of using protective structures for intensive vegetable cultivation have encouraged studies to provide a better indoor environment for improving crop production performance. Studies by MARDI indicate that the yield of vegetable per unit area is 2–4 times higher in shelters compared to open field production. However, study for the design of the shelters and the indoor microclimate to optimize crop production has received inadequate attention. The protective structures used for vegetable production are rain shelter (RS) and insect proof netted structure (IPNS). This study at MARDI investigated the indoor environment in a netted rain shelter. The shelter incorporated a polyethylene (PE) film roof to eliminate the rain with jack roof to provide natural ventilation and insect proof netting sides to keep out insects. The year long study on thermal environment, measured the air temperature inside and outside the shelter, soil temperature and solar radiation inside the shelter during vegetable cultivation. Thermal environmental patterns under the shelter were developed to determine the levels of environmental comfort and the design of control system to meet crop requirement. The internal environment of rain shelter depends on radiant heat received by the structure. Excessive radiation will cause heat stress to the plants and depress the physiological functions. This excessive heat is important to be determined and removed to improve the indoor environment. The developed environmental patterns can be used to determine the strategic steps in controlling the effects of heat stress and used as guideline in the design of more effective environmental control system.

Full Text (548 KB)