Examining the effect of different polycarbonate greenhouse cover materials on tomato yield and plant development with thermal imaging

In this study, the effects of different polycarbonate (PC) greenhouse covering materials on the environmental microclimateand plant growth were examined using three research greenhouses. Two types of PC covering materials were tested: the first greenhousewas covered with UV-additive PC (UV PC), the second greenhouse with UV+Infrared (IR) additive PC (UV+IR PC), and the third(control) greenhouse had UV-additive PC on the sidewalls and polyethylene (PE) covering material (UV PC+PE) on the roof. Themeasured fundamental parameters included total radiation transmittance, photosynthetically active radiation (PAR) transmittance,temperature, and relative humidity. Plant development was monitored and leaf temperatures were measured using a thermal camera atvarious points during the growing season. Tomatoes were cultivated in the greenhouses to evaluate the effects of the different coveringmaterials on plant growth, development, yield, and fruit quality. Plant parameters assessed included height, stem diameter, leaf number,and yield, while fruit parameters analyzed were average fruit weight, diameter, soluble solids content (SSC), electrical conductivity (EC),pH of the fruit juice, and lycopene content. Additionally, plant canopy temperatures were monitored via a thermal camera. The initialtotal radiation transmittance values for the UV PC, UV+IR PC, and UV PC+PE were 49.4, 49.2, and 62.6%, respectively. By the end ofthe study, these values decreased by 25.1, 28.9, and 10.7%, respectively. Similarly, initial PAR transmittance values for the UV PC, UV+IRPC, and UV PC+PE were 54.7, 49.3, and 54.1%, respectively, with reductions of 27.2, 25.6, and 9.4%, respectively, observed at the end ofthe study. The highest total radiation and PAR transmittance throughout the study period were recorded in the PE-covered greenhouse.In terms of yield, the UV+IR PC greenhouse covering material produced the highest total yield across both growing seasons.