Agrivoltaics for sorghum, soybean grain
In the US, pv magazine reported that a research team from the United States’ University of Illinois Urbana-Champaign has experimentally examined how shading in agrivoltaic systems influences sorghum and soybean grain yields, focusing on source-sink dynamics, which are the processes by which plants produce and allocate assimilates like sugars during growth.
“To our knowledge, no previous studies have conducted source–sink manipulations within solar arrays to investigate the physiological mechanisms governing grain weight during grain filling,” corresponding author DoKyoung Lee told pv magazine. “If shading from PV panels results in a yield penalty, it is essential to understand not only the overall yield reduction but also which specific yield components are affected. In this study, we examined both yield and yield components, such as grain number and grain weight, in sorghum. Further, we elucidated the distinct physiological mechanisms underlying grain weight by assessing alterations in source and sink strength.”
The research took place during the growing seasons of 2023 and 2024 at Solar Farm 2.0 in Champaign, Illinois, USA, a project that generates approximately 20,000 MWh/year for the university. Individual PV panels were 1 m wide by 2 m long, mounted on 1.5 m brackets, with a 5.5 m spacing between rows. Panels are installed on a north-south axis with single-axis tracking, allowing them to rotate east-to-west. Eight plots – four sorghum and four soybean – were planted inside the PV plant, while the other eight served as controls under full-sun conditions. Each plot had dimensions of 4 m wide by 6 m long, with five rows spaced 0.75 m apart – two rows on the east side, two rows on the west side, and one in the middle.
“Soybean showed a yield penalty regardless of shading intensity (across different rows) between PV panels. In contrast, sorghum showed a smaller yield penalty than soybean, and this penalty diminished as shading decreased in the middle row, resulting in no yield penalty,” Lee said about the test results. “Grain formation in sorghum was also sensitive to resource availability, but sorghum was able to compensate as it increased grain size when resources were sufficient.”
Category: Food & Agriculture
