Speaker
Description
Introduction:
Agrivoltaics has been touted as a possible solution to the competition for land between food and energy production. However, so far, results have been mixed, since different crops appear to respond differently among different climates, PV panel arrays, and even seasons and years within a system. It has been suggested that warmer and drier climates would show the greatest benefits from APV, since abundant sunlight may be enough for concurrent energy and crop production, while heat amelioration from shading might reduce crop plant stress. This expected benefit is purported to allow growing more diverse crops in these climates, a potential benefit to nutritional security, and an important aspect in the economic viability of agrivoltaics in the Arava region in Israel, which experiences very hot summers and dry, mild winters. Our pilot studies set out to empirically test the potential benefits and drawbacks of PV shading on cropping systems.
Methods:
We tested responses of several crops to PV shading in two different systems: stilt-mounted (4m) over field and vegetable crops, and ground-mounted (1.5m) over vegetable crops. The ground-mounted system was built on soilless drainage lysimeters, which allowed us to measure crop water requirements and water use efficiency. In both systems, we tracked plant vegetative growth, soil water content, incoming photosynthetically active radiation (PAR), micrometeorology, and measured final biomass and yield.
Agronomic benefits:
Shading from PV panels consistently helped keep soil water content higher and air temperature lower. Vapor Pressure Deficit was reduced under panel shading at a rate directly proportional to the temperature in unshaded control plots. As a result, water requirements were reduced by ~10%.
Leafy greens (chard) and tomatoes showed similar yields across shading treatments, but tomato fruit quality did slightly improve under stilt-mounted panel shading. Garlic showed no shade effect on growth, but the season was cut short, and we did not reach a good bulb harvest in any treatment.
Agronomic costs:
Winter crops
Sweet potato showed mild yield loss in response to shade, though no loss of vine biomass or cover. Perhaps slower tuber biomass accumulation. Beetroot shows significant yield loss in ground-mounted and stilted PV systems during the cold season, but beet leaf biomass is similar in all shade conditions, the same as other leafy greens we tested.
Spring/summer crops
Zucchini summer squash showed delayed and reduced fruit production under shade. Corn showed mixed results in 2024 when crops were not fertilized. However, in 2025, fertilized spring corn showed similar early (March) growth under shade, but later (April-May) vegetative growth and corn-cob yield were significantly reduced under shaded conditions.
Discussion:
The drop in yield was significant, despite metrological and physiological measures showing reduced crop stress. The observed reduction in system water requirements was concurrent with a reduction in agronomic yield, such that water use efficiency was reduced in warm-season crops.
Overall, the yield reductions we observed are similar to previously reported experiments and meta-analyses, most of which were conducted in cooler regions. Despite the assumption that crops would lose minimal yield or even improve under PV shading in hot and dry conditions, our interim results suggest that such benefits may occur in a very limited set of crops, or perhaps with a lower reduction in solar radiation (RSR). We used a RSR of ~40%, which is on the high end of most experimental systems used at more mesic regions. Most importantly, our results highlight the need for continued and expanding empirical testing of this emerging agroecosystem, and the need for publishing all results to avoid false representations that could drive large-scale effects on food production and the agricultural economy.
Keywords: Agrivoltaics, Dryland agriculture, Sustainable agriculture, WEF nexus.
