Work

Reduced summer carbon dioxide efflux from semi-arid agrivoltaic compared to conventional horticultural soil

Year: 2026

Type: article

Abstract: Agrivoltaic (AV) systems that combine horticultural crops with photovoltaic (PV) infrastructure on the same land parcel can provide mutual benefits for crop performance, electricity production, and water use in semi-arid climates. Whether semi-arid AV systems provide additional benefits for soil development and carbon (C) accumulation remains unclear. Larger aboveground biomass and yield production, which has been observed in semi-arid AV for certain crops, may accelerate C loss by supporting more continual and extensive microbial and root respiration, resulting in net zero or negative change in soil C over a growing season. Alternatively, AV systems may retain more soil C by reducing stress-induced respiration. To test these contrasting hypotheses, we compared crop biomass and yield, soil carbon pools, and semi-continuous microclimate and respired carbon dioxide (CO 2 ) emissions for two horticultural crops grown in an experimental AV site in southern Arizona, USA. Over one summer growing season, we observed an approximately 9% reduction in daily mean soil CO 2 efflux from legume (cowpea, Vigna unguiculata ) and 48% reduction from aromatic herb (basil, Ocimum basilicum ) beds, with the strongest impacts of AV appearing during the early monsoon season when plants were mature. On diel timescales, AV soil CO 2 efflux peaked later in the day compared to conventional horticultural beds, corresponding to lagged increases in soil temperature under solar panels. Smaller CO 2 efflux in AV coincided with a doubling of aboveground crop biomass. Both crops and cover types experienced similar declines in soil C over the growing season, indicating that reduced CO 2 efflux did not correspond to a measurable increase in soil C during this period and highlighting the need to resolve other C transformation and loss pathways. Complementing its well-described food-water-energy benefits, we find potential for AV to reduce soil CO 2 efflux and urge future research to identify changes to soil C cycling that result from the addition of PV to horticultural landscapes.

Source: Environmental Research Letters

DOI: 10.1088/1748-9326/aeb1dd