Effect of shading determined by photovoltaic panels installed above the vines on the performance of cv. Corvina (Vitis vinifera L.)

Agrivoltaic (AV) is a new concept integrating both the production of agricultural crops and electric power on the same land area through the installation of photovoltaic panels some meters above the soil surface and the crop canopy. In the present situation of energy demand from renewable sources, agrivoltaic systems with vines and/or fruit trees under the photovoltaic panels has still received poor attention. On the basis of this lack, the present 3 -year study (2017-2019) aimed to investigate the effects of photovoltaic panels on grapevines of variety Corvina (Vitis vinifera L.). In particular, the experiment was carried out in a vineyard located in Northern Italy, Veneto region, with the Corvina (Vitis vinifera L.) grape variety and the effects of shading by the panels on both phys-iological activities and vine performances were analyzed. Photovoltaic panels reduced both air and soil maximum temperature by 1-2 degrees C. Vine transpiration on early morning was 0.83-0.90 in AV vs. 1.03-1.21 mmol H2O m- 2 s- 1 in full sun (FS) vines, whereas at midday values were significantly higher in AV vines (0.56-0.65) with respect to FS vines (0.38-0.44 mmol H2O m- 2 s-1). Photosynthesis followed the same pattern with values significantly higher in the FS vines at morning (9.34-11.03 mu mol CO2 m- 2 s-1) with respect to AV vines (5.24-6-84 CO2 m- 2 s- 1), and the opposite was detected at midday, with 1.57-3.05 mu mol CO2 m- 2 s- 1 in AV vines and 0.58-2.05 mu mol CO2 m- 2 s- 1 in FS vines. The stem water potential was significantly reduced (less negative) by shading of the panels both at morning and at midday of values around 1-6 MPa thus indicating less stressful conditions for AV vines. The photovoltaic panels affected the microclimate of the vineyard (lower air and soil temperature, higher soil matric potential) in the three seasons. Vine productivity parameters (yield, cluster number and weight) were influenced to a limited extent; anthocyanins, TSS and polyphenols were reduced in grape must from AV vines. These findings show that the panels affect the vines microclimate and physiology and that yield reductions under AV are observed, but under hot and dry weather conditions results could be very interesting either for energy or fruit production. Further experiments need to be conducted in such environmental conditions also in the perspectives of the climate change.