Field crops can tolerate shade

August 21, 2026

Source: E & M powernews

A field study by the University of Hohenheim shows that five crop plants adapt their photosynthesis to partial shading in agroforestry and agri-PV systems.

Crop plants can adapt to changing light conditions more effectively than previously assumed. This is shown by a field study conducted by the University of Hohenheim in Stuttgart in collaboration with the Jülich Research Center. The study examined barley, corn, cabbage, potatoes, and field beans under real-world conditions in agroforestry and agri-photovoltaic (agripv) systems.

The researchers conducted the studies in 2023 and 2024 at five locations in Germany. They analyzed the photosynthesis of five commonly grown varieties. Fully sunlit areas served as a control. Using a mobile photosynthesis measurement system, the team recorded key physiological parameters directly from the leaves.

The most important finding: Under partial shading, both dark respiration and the light compensation point decreased in all five crops. According to doctoral candidate Jennifer Moore, this means that the plants lose less CO₂ through respiration and, at the same time, require less light to fix carbon. The plants can thus physiologically adapt to lower light availability.

Plants Respond to Light Availability

“It is particularly noteworthy that this effect occurred in all the crops studied, even though they typically do not grow under shade,” says Prof. Andreas Schweiger, head of the Plant Ecology Department at the University of Hohenheim. The results suggest that field crops possess greater adaptability than previously assumed.

According to the researchers, these adaptations were observed regardless of location, soil type, farming practice, and shading conditions. Moderate shading, therefore, does not necessarily lead to the plants being overwhelmed. At the same time, the reactions vary depending on the cropping system.

Under photovoltaic modules, photosynthetic rates reportedly remained relatively stable in most cases. In agroforestry systems, the measured values fluctuated more significantly. The researchers attribute this, among other things, to the more irregular shading patterns created by tree canopies. “Not all shade is the same,” says Moore. Areas with persistent heavy shading should therefore be avoided whenever possible.

Corn Proves More Sensitive

The researchers also observed differences among crop types. Corn tended to be more sensitive to reduced light availability than the other plants studied. As a C4 plant, corn is adapted to high temperatures and intense sunlight. In weaker light, it is less able to fully utilize its photosynthetic capacity, explains Moore.

According to the University of Hohenheim, the results could aid in the planning of agroforestry and agri-PV systems. Physiological parameters such as dark respiration and the light compensation point could be used to identify more shade-tolerant varieties and to better tailor suitable crops to specific light conditions.

This also opens up new possibilities for plant breeding. According to Schweiger, the adaptability already present in conventional varieties could serve as a starting point for the targeted selection and breeding of plants for partially shaded cropping systems.

Shading Helps Combat Heat

Agroforestry and agri-PV are also expected to contribute to more efficient use of agricultural land and to mitigate the effects of heat and drought. Shading can alter the microclimate, lower soil temperature, and help retain soil moisture for longer. According to the researchers’ assessment, periods of heat and drought could limit plant growth more severely in the future than the moderate shading provided by trees or solar panels.

However, the study does not prove that physiological adaptation automatically leads to higher yields. According to the university, the yield data collected varied depending on location and crop type and did not paint a uniform picture.

Details on the University of Hohenheim’s Agri-PV study are available online. (sh)

Author: Susanne Harmsen