IMPACTS OF ROOF–MOUNTED PHOTOVOLTAIC PANEL SHADING AND SOIL MULCHES ON GREENHOUSE ENERGY USE AND CUCUMBER YIELD

Greenhouse farming has become an increasingly vital component of modern agriculture, providing a controlled environment that supports crops year-round. A field experiment was conducted to test the effect of shading photovoltaic panels and covering the soil with polyethylene on indoor air temperature and relative humidity. The experiment examined the impact of shading on cucumber production during the autumn and spring seasons of 2024-2025 in the Talkaif district of Nineveh Governorate, North Iraq. Statistical analysis was adopted to analyse the experimental data. Fully mulching substantially reduces soil evaporation, and, combined with shading, helps reduce temperature variations inside the greenhouse. The temperature variations in the shaded greenhouse, with black mulch for the soil in both seasons, ranged from 5.9 to 11 oC. The temperature variations in the shaded greenhouse, which used white mulch, ranged from 6.2 to 13.9 °C in both seasons. The shading with photovoltaic panels of both types and the mulching colors achieved a surplus in cucumber crop yield in the autumn season compared to the conventional greenhouse, ranging from +20.56 to +42.12 g. plant-1. Although there was no increase in cucumber crop yield in the spring, the yield was higher than in the autumn. When comparing the yield in the shaded greenhouse for the same spring season with the conventional greenhouse, the results ranged from -121.15 to +26.05 g.plant-1. The increase in energy compensated for the decrease in cucumber crop yield, amounting to +112.74 kWh. Autumn season-1 and +116.98 kWh. Spring season-1, respectively.