Effect of Thermal Screen Position on Greenhouse Microclimate and Impact on Crop Growth and Yield

Abstract

Worldwide, researchers are developing methods in which producers can obtain higher yields and conserve more energy in greenhouse crop cultivation. To achieve this, thermal screens are deployed during cold nights and rolled up during the daytime. The positioning of these screens causes a reduction in the amount of solar radiation (SR) received by greenhouses, especially the single span. The impact of thermal screen position on the receipt of SR, temperature, relative humidity (RH), vapour pressure deficit (VPD), fuel consumption, and the consequent effects on crop yield and growth were investigated in this study. Two greenhouses with similar dimensions and structure but different thermal screen positions were designed, namely R-greenhouse (RGH) with thermal screens at the centre of the roof and Q-greenhouse (QGH) at five degrees (5o) Northward. Strawberries were cultivated as study crops. Statistical analysis of the recorded data of greenhouse microclimate parameters, crop growth, and yield showed that both greenhouses performed similarly in energy savings, and there was no significant difference regarding temperature, RH, and VPD. However, there were significant differences in the crop growth and yield obtained in the QGH compared to RGH. This can be attributed to the higher amount of SR received by the QGH than the SR that was received by the RGH, which was achieved because the thermal screen was installed on the north side of the Q greenhouse.