In this article, we present the latest results from our two experimental agrivoltaic sites for field crops.
Our agrivoltaic sites for field crops
We are conducting field crop experiments at two agrivoltaic sites. Scheduled for commissioning in 2022 and 2021 respectively, our Valpuiseaux and Channay sites will enable us to work alongside our partners (Agrinovex, Agrosolutions (subsidiary of Invivo) for Valpuiseaux, and Agronov, Agrosolutions, Dijon Céréales and the Côte d'Or Chamber of Agriculture for Channay), to study the benefits for field crops of installing vertical panels.
Find out more about our Valpuiseaux and Channay sites and discover the results for 2022, visit the dedicated pages on our website.
Our field crop experiments
To maximize feedback, we grow various crops on the 13 strips protected by vertical panels on the Channay site. In 2023, the following crops were grown organically on this site:
- Strips 0 and 1: Aromatic plants
- Bands 2 and 3: Lavandin
- Band 4: Cameline
- Strips 5 to 7: Alfalfa
- Strips 8 to 10: Winter wheat
- Bands 11 to 13: Lenses
On the same site, grass strips were planted between the crop strips and under the panel rows.
Follow-up protocol
All our experimental sites are subject to a monitoring protocol enabling us to produce references that will enrich our future agrivoltaic power plants, in order to maximize their agronomic and environmental benefits.
The sensor network
Sensors play a crucial role in these results. Four types of aerial sensors are installed on site: weather station, anemometer, rain gauge and radiation sensors (PAR). There are also sensors measuring temperature and water tension (on the Channay site) / soil moisture (on the Valpuiseaux site).
They collect data in real time and enable us to carry out a microclimate analysis on the crops to compare the effects of the system with the control zone without panels.
The photo on the right shows a set of capacitive probes that enable us to measure the water content of the soil at Valpuiseaux throughout the day.
Analyses and parameters monitored at the agrivoltaic site
Agronomy and soil
On an agrivoltaic site, agricultural production remains the main activity. This is why agronomic monitoring is the first thing we do on our experimental plots. Analyses of the quantity and quality of each crop allow us to test the effect of the panels on the crops. Physical, chemical and biological analyses enable us to monitor soil quality and its evolution. Grass strips are also monitored.
Energy
Farming is the main activity of an agrivoltaic site, but these farms also aim to produce electricity. For this, a specific design is required to combine these two activities while maintaining the expected yield. It is therefore essential to monitor the park's production using a performance analysis that takes into account the temperature of the modules and the irradiance received.
One of the irradiance components essential to this analysis is the albedo (fraction of light reflected or scattered by a non-luminous body) of crops, which varies over the year, depending on the maturity and height of the plant cover.
This is a subject we'll be covering in detail in an upcoming article. Don't miss it!
Subscribe to the Ombrea newsletter
Discover our results for 2023 on the Channay site
Agronomic results on crops
Wheat and lentil yields were higher on the Channay site with a soil of low agronomic potential, while yields were maintained on the soil with high agronomic potential (same result in 2022). BTH (Blé Tendre Hiver) yields were 26% higher in the shaded zone, and lentil yields 17.8% higher, than in the control zone. The presence of panels had no significant effect on alfalfa production.
Wheat quality at harvest is fairly stable considering the indicators studied (Specific Weight, Thousand Grain Weight, Grain Moisture and Protein Content). In particular, specific weight rose by 2% between panels, following the same trend as in 2022. Protein content was up by 3%.
These very encouraging results, in a context of low rainfall, will be challenged in future experimental years.
Impacts in terms of microclimate and adaptation to climate change
On current analyses, air temperature remains unchanged. Punctual increases in temperature have been observed between panels (around 1.8°C, probably due to the wind breeze effect), and there have also been punctual decreases in air temperature during shady periods, but the differences are small. As a result, thermal time is rather preserved (+2.8% at harvest between panels, which is negligible; the maintenance of thermal time is in line with the literature).
On the other hand, there are differences at ground level. The ground temperature measured over the warm period is generally lower in the area with panels. Depending on the climatic conditions of the day and the type of cover considered, soil temperature can be reduced by around 2.5°C. With regard to water tension, although an improvement in water status is expected between panels, we cannot draw any conclusions at this stage, as analyses are still in progress.
The wind-breaking effect of vertical panels, particularly on westerly dominances, was observed. There was an average 18.5% reduction in gusts (39.6 km/h in the control zone), as well as a 54% drop in average wind speed between panels.
To find out more about the results for the Channay and Valpuiseaux sites :
