Vine Performance, Single-Leaf and Whole-Canopy Gas Exchange Under Agrivoltaics Cover in Malvasia di Candia Aromatica and Cabernet Sauvignon Grapevines

Abstract

Background and Aims: Under a surge of interest in the dual use of land, very scant information is still available about physiological and agronomical adaptations of the grapevine grown under agrivoltaics (AV) panels and their compatibility with light energy capture.

Methods and Results: A setup of permanently horizontal AV panels mounted from veraison until harvest over Cabernet Sauvignon (CS) and Malvasia di Candia aromatica (MC) row sections was compared with an open-field (OF) row section of the same cultivars. Uninterrupted diurnal and seasonal whole-canopy gas exchange measurements were taken from August 9 to September 29. In contrast, total light interception, leaf gas exchange and water status, cluster temperature, and photochemical quantum yield of photosystem II (φPSII) readings were concentrated on August 13–14. Vegetative growth, yield components, ripening dynamics, grape and wine composition, and volatile and bound aromas were performed. Based on diurnal and seasonal direct and diffuse light measurements, panels cut incoming light by about 47%. In contrast, the reduction of the whole-canopy net carbon exchange rate (NCER) and transpiration (T) was only 7%–9%. Canopy water use efficiency (WUE) was not significantly affected, although, in CS, WUE lowered when panels cast maximum shade over the central part of the day. With yield components not being affected, under AV, harvest was delayed by 17 and 12 days versus OF in CS and MC, respectively. However, while technological maturity was comparable in MC under OF and AV, the latter had lower monoterpenes and fermentative esters, which might hint at less floral and fruity notes. The rainy late season compromised grape maturity on the CS–AV vines, and the final wines were lighter in color and body.

Conclusions: Under the specific panel’s configuration, the whole-canopy gas exchange was minimally affected in front of a 47% light depletion. Panels caused a consistent ripening delay that was detrimental to free-volatile wine components in MC. In contrast, it worsened grape and wine quality in CS primarily due to unfavorable late-season weather.