Agrivoltaics mitigate drought effects in winter wheat

Climate change is expected to decrease water availability in many agricultural production areas around the globe. At the same time renewable energy concepts such as agrivoltaics (AV) are necessary to manage the energy transition. Several studies showed that evapotranspiration can be reduced in AV systems, resulting in increased water availability for crops. However, effects on crop performance and productivity remain unclear to date. Carbon-13 isotopic composition (delta C-13 and discrimination against carbon-13) can be used as a proxy for the effects of water availability on plant performance, integrating crop responses over the entire growing season. The aim of this study was to assess these effects via carbon isotopic composition in grains, as well as grain yield of winter wheat in an AV system in southwest Germany. Crops were cultivated over four seasons from 2016-2020 in the AV system and on an unshaded adjacent reference (REF) site. Across all seasons, average grain yield did not significantly differ between AV and REF (4.7 vs 5.2 t ha(-1)), with higher interannual yield stability in the AV system. However, delta C-13 as well as carbon-13 isotope discrimination differed significantly across the seasons by 1 parts per thousand (AV: -29.0 parts per thousand vs REF: -28.0 parts per thousand and AV: 21.6 parts per thousand vs REF: 20.6 parts per thousand) between the AV system and the REF site. These drought mitigation effects as indicated by the results of this study will become crucial for the resilience of agricultural production in the near future when drought events will become significantly more frequent and severe.

Automated summary

Climate change reduces water availability in agricultural areas, while agrivoltaic systems help manage energy transition. This study analyzed the carbon isotopic composition in grains and grain yield of winter wheat in an agrivoltaic system, finding that although grain yield did not significantly differ compared to a reference site, the carbon isotopic composition showed significant differences, indicating drought mitigation effects.