Solar panels above orchards lower temperature, help conserve water

The results of research carried out in the south of France showed that solar panels installed above apple, cherry, and nectarine plantations reduce heat and contribute to maintaining soil moisture in periods of high temperatures.

Agrisolar is becoming an increasingly popular solution. It is a combination of agriculture and electricity generation from photovoltaic panels. Such devices are usually mounted at a height of almost two and a half meters in rows so that the land below can be used to grow vegetables and fruit or for cattle grazing.

In the departments of Bouches-du-Rhône and Drôme in the south of France, the company Sun’Agri studied the performance of agrisolar systems in combination with fruit farming. For three years, the company monitored a series of parameters in orchards with apple, cherry, and nectarine trees under solar power panels. They were compared against equivalent orchards that were not covered.

Orchards covered with solar panels require less irrigation

The analysis reveals that the temperature on the test estate in Bouches-du-Rhône was 3.8 degrees Celsius lower than in ordinary orchards. In addition, soil moisture was 14% higher. The company also found that the agrivoltaic system contributed to water conservation. The need for irrigation from 2019 to 2021 was up to 30% lower than on the reference plots or 22% on average.

With its dynamic panels, Sun’Agri adjusts the orientation of the photovoltaic panels to the physiological needs of the fruit trees, in accordance with the weather conditions.

Solar panels provide a favorable microclimate for plant growth

Micrometeorological sensors were located at different heights under the panels. They measured temperature, air humidity, and sunshine.

With the help of special devices for measuring active radiation for photosynthesis, the researchers tracked the growth of plants and their needs. Sensors were placed on the trees themselves to monitor water levels, functioning, stress, and the temperature of their organs. Ground sensors measured the amount of water in the soil.

The study also showed that soil water availability decreased less under solar panels. The effect was attributed to the microclimate regulation in the shade of the panels, which improved the conditions for the plants and reduced transpiration and watering needs.

In 2021, the company said its panels reduced the risk of frost for vines below. When the temperature is dropping to a level threatening the crop, photovoltaic shift to a horizontal position, parallel to the ground, so that they cover almost 40% of the total area. It helps retain the heat stored in the soil until dawn. The extra couple of degrees are particularly beneficial in the prevention of frost, protecting the most sensitive parts of trees and vines, such as buds and flowers.