Influence of agrophotovoltaic on vine and must in a cool climate
The current energy crisis means that interest in agrophotovoltaics has increased significantly. The reason behind this is that the system aims to combine agricultural production with energy production. During the three-year period from 2020 to 2022, the effects of photovoltaic panels on the vine, the yield and the quality of the must were studied in Walenstadt in northern Switzerland, an area with a cool, humid climate. 65 Pinot noir vines were planted in the 160m2 study area. Because of the large edge effects, only 3 repetitions with 4 vines each could be created. A significantly lower leaf infestation by Plasmopara viticola was observed among the panels in each of the three years. However, in 2021 a significantly lower grape infestation was observed with an extremely high infestation pressure. In contrast, significantly higher powdery mildew leaf infestations were observed in 2020 and 2022, with infestations well below the economic threshold. During the three-year study period, the sugar content among the panels was significantly lower at around 0.9 to 1.8 Brix, and the total acidity was significantly higher between 1 and 1.3 g/l. These results indicate an approximate 1-week delay in ripening. Growth was optically stronger underneath the panels throughout the dry years 2020 and 2022, but only in the latter was it possible to measure a significantly higher pruning weight. The significantly lower value of the relative carbon isotope composition (Δ13C) in must sugars under the panels indicates greater water stress compared to the control, which can be attributed to reduced transpiration under the panels.
Conclusion: In the three years observed no significant negative impact of the photovoltaic panels could be determined, either on the yield or on the components of the must. The delay in ripening is usually a positive aspect, as is the reduced pressure from downy mildew. However, there is still a need for optimisation in construction so that unhindered mechanical cultivation is possible.
Issue: OENO Macrowine 2023
1 ZHAW Zurich University of Applied Sciences
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Agrophotovoltaic, Plasmospara viticola, berry composition, water stress