Microclimate under agrivoltaic systems: Is crop growth rate affected in the partial shade of solar panels?

Mean daily air temperature and humidity were similar in the full sun treatments and in the shaded situations, whatever the climatic season. On the contrary, mean daily soil temperature significantly decreased below the PVPs compared to the full sun treatment. The hourly pattern of crop temperature during day-time (24 h) was affected in the shade. In this experiment, the ratio between crop temperature and incident radiation was higher below the PVPs in the morning. This could be due to a reduction of sensible heat losses by the plants (absence of dew deposit in the early morning or reduced transpiration) in the shade compared to the full sun treatment. However, mean daily crop temperature was found not to change significantly in the shade and the growth rate was similar in all the treatments. Significant differences in the leaf emission rate were measured only during the juvenile phase (three weeks after planting) in lettuces and cucumbers and could result from changes in soil temperature. As a conclusion, this study suggests that little adaptations in cropping practices should be required to switch from an open cropping to an agrivoltaic cropping system and attention should mostly be focused on mitigating light reduction and on selection of plants with a maximal radiation use efficiency in these conditions of fluctuating shade.