By Andi Anderson
Researchers in Illinois are working to improve the production of energy crops that support the growing demand for sustainable aviation fuel.
Two new studies from the University of Illinois Urbana-Champaign offer clear guidance for farmers by focusing on harvest strategies for switchgrass and nutrient management for Miscanthus. These findings help address key gaps in long-term crop performance and profitability.
D.K. Lee, senior author of both studies, explained the goal of this work, saying, “We have come a long way in our understanding of purpose-grown energy crops for SAF, but we still need to optimize agronomic management practices, like harvesting and nutrient management, to reduce production costs and incentivize growers.”
Earlier research often covered only early growth years or small locations, but these new studies provide broader, long-term insights.
The first study examined two harvest methods for switchgrass. Lead researcher Muhammad Umer Arshad noted that “Harvesting operations account for 60-80% of the total production costs for switchgrass.” His team compared the traditional stepwise approach with the integrated method, which combines mowing and raking in one pass.
After studying 125 commercial sites, they found that the integrated method works best for small fields and low yields, lowering greenhouse gas emissions by 9% and reducing energy use by 5%.
For large, high-yield fields, the stepwise method was more efficient, lowering harvesting costs to $37.70 per ton and producing the lowest emissions. These results show that harvest choices should match field size and yield levels.
The second study focused on Miscanthus, a perennial crop whose yields decline with age. Researcher Nictor Namoi found that both tiller mass and density rise from year one through year four, and nitrogen applications increase both factors.
He explained, “We found that both tiller mass and density increase from the first year of establishment to the fourth year, and if you apply nitrogen, you get an increase in both factors.” Over time, tiller mass becomes the first component affected as nutrients are removed during harvest.
He also discovered major declines in soil phosphorus and potassium, showing that long-term productivity requires managing all three nutrients.
Together, these studies provide practical guidance to help energy crop growers improve yields, cut costs, and support the expanding bioenergy sector.
Photo Credit: istock-pixeldigits
Categories: Illinois, Harvesting