In the heartland of America, a remarkable transformation is taking shape as the humble switchgrass, a perennial prairie species long rooted in Midwestern soils, emerges as a promising contender to revolutionize sustainable aviation fuel (SAF) production. Groundbreaking research conducted by the University of Illinois Urbana-Champaign unveils the multifaceted economic and environmental advantages of cultivating modern energy-type switchgrass cultivars. These findings hold the potential to reshape bioenergy landscapes while addressing urgent climate change challenges associated with the aviation industry.
Sustainable aviation fuel has become a pivotal element in efforts to cut the carbon footprint of air travel, with the U.S. Department of Energy’s Sustainable Aviation Fuel Grand Challenge aiming to scale production to an ambitious 35 billion gallons by 2050 and reduce greenhouse gas emissions by half. Switchgrass stands out among several dedicated bioenergy feedstocks due to its ability to produce substantial biomass yields annually without the need for frequent replanting. Furthermore, it requires substantially less nitrogen fertilizer compared to traditional crops like corn, alongside contributing valuable ecosystem services such as soil stabilization and nutrient cycling.
Decades of research into switchgrass bioenergy potential have previously been limited by smaller plots, older forage cultivars, and underestimation of necessary fertilizer inputs. Addressing these gaps, two recent extensive field studies led by U. of I. researchers utilized high-yielding “energy” cultivars Independence, Liberty, and Carthage, planting them alongside forage cultivars Shawnee and Sunburst on marginal lands across Illinois, Iowa, Nebraska, and South Dakota. By incorporating realistic nitrogen fertilizer regimes—28 and 56 kilograms per hectare—the researchers conducted comprehensive economic assessments, shedding light on profitability and environmental impacts on a broader and more applicable scale than ever before.
Postdoctoral researcher Muhammad Umer Arshad’s economic analysis revealed striking differences in profitability among cultivars and locations. Energy-type cultivars Independence and Liberty consistently outperformed forage varieties across all sites. However, optimal nitrogen fertilizer rates for maximizing profit exhibited regional variability. While 56 kilograms per hectare generally increased biomass yields, in select locations the lower input rate of 28 kilograms per hectare delivered superior profit margins. These insights underline the importance of locally optimized nutrient management strategies for bioenergy crop production.
Interestingly, the profitability of cultivars also corresponded clearly with USDA plant hardiness zones. Independence showed greatest financial returns within zone 6a, Liberty excelled in zone 5b, and Carthage dominated in zone 4b. This geographic delineation suggests that cultivar selection can be finely tuned to regional climates, thereby enhancing farmers’ opportunities to reclaim and monetize marginal lands that are otherwise unprofitable for conventional commodity crops. The dual promise of sustainable biomass production and ecosystem service provision positions switchgrass as a robust tool in the green energy transition.
Complementary to the economic investigations, ecosystem services benefits were evaluated under field conditions in Illinois by postdoctoral fellow Nictor Namoi. Namoi explored greenhouse gas fluxes including carbon dioxide and nitrous oxide emissions, as well as nitrate leaching, comparing switchgrass plots to continuous no-till corn. Surprisingly, nitrous oxide emissions and nitrate leaching were markedly reduced—by up to 80%—in switchgrass systems relative to corn, a finding attributed to the significantly lower nitrogen fertilizer application on switchgrass fields. These reductions represent substantial progress in mitigating potent greenhouse gases and nutrient pollution from agriculture.
Conversely, carbon dioxide emissions presented a more complex picture. After two years, CO2 fluxes were observed to be over 50% higher beneath switchgrass than corn plots. This counterintuitive outcome is linked to the profound difference in belowground biomass: switchgrass root systems harbor approximately five times more root mass than corn. Elevated root respiration, a natural metabolic process producing CO2, drives this increased emission. However, this root biomass is not only an emission source but also a carbon sink; it plays a critical role in long-term soil carbon sequestration, storing about 10 megagrams of carbon per hectare, far exceeding typical row crops.
The ability of switchgrass to thrive on marginal lands—soils that are unprofitable or unsuitable for staple commodity crop production—offers an additional sustainability advantage. By directing biomass cultivation to marginal sites, switchgrass reduces competition with food crops, preserving prime agricultural lands while contributing renewable feedstocks for biofuels. This strategic land use minimizes the risks associated with land-use change that often undermines the environmental benefits of bioenergy crops.
Despite the promising competitive advantages identified, the current economic environment presents challenges. Low commodity and oil prices have dampened immediate demand for purpose-grown bioenergy crops like switchgrass. Yet, as global trade dynamics and tariff policies evolve, the market for sustainable aviation fuel is poised to expand rapidly. The rigorous agronomic, economic, and environmental data from these research efforts equip stakeholders with the knowledge necessary to integrate switchgrass efficiently into SAF supply chains when the time is ripe.
University of Illinois professor DoKyoung Lee, senior author of both studies, emphasizes that these investigations deliver a refined understanding of switchgrass performance at scales relevant to real-world farming. By moving beyond the confines of small-plot and forage-based research into modern energy cultivars evaluated across diverse regions, this research maps a pathway toward more resilient and profitable biomass production systems. Lee further highlights that the sustained belowground carbon storage capacity of switchgrass roots strengthens its candidacy as a cornerstone of climate-smart agricultural practices.
The first study, published in GCB Bioenergy, employed rigorous economic methodologies including Data Envelopment Analysis and cost-benefit approaches to assess the relative profitability of bioenergy versus forage switchgrass types. The second study, featured in the Journal of Environmental Quality, presented the ecosystem service evaluations, documenting the nuanced roles switchgrass plays in greenhouse gas dynamics and nutrient cycling at field scale. Both received considerable support from the U.S. Department of Energy’s Bioenergy Technologies Office and associated research centers, underscoring the strategic national importance of this work.
Additionally, Lee’s affiliation with multiple interdisciplinary institutes at U. of I.—including the Institute for Sustainability, Energy, and Environment, the Agroecosystem Sustainability Center, the Center for Advanced Bioenergy and Bioproducts Innovation, the Center for Digital Agriculture, and the National Center for Supercomputing Applications—attests to the integrative nature of this research. By combining agronomy, environmental science, economics, and advanced computational tools, the team paints a comprehensive picture of switchgrass’s potential to reshape renewable bioeconomies.
As the aviation sector grapples with mounting pressure to decarbonize, the emergence of switchgrass as a bioenergy feedstock embodies both innovation and pragmatism. Capitalizing on the switchgrass advantage requires continued refinement of cultivar selection, nitrogen management, and ecosystem service quantification in diverse settings. Through such integrated approaches, the Midwestern prairie grass could soon power the jets of tomorrow, grounding a future where sustainable fuels soar skyward.
Subject of Research: Sustainable bioenergy feedstock development focusing on switchgrass cultivars for sustainable aviation fuel production and associated economic and ecosystem service evaluations.
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Web References:
- University of Illinois Urbana-Champaign: http://illinois.edu/
- U.S. Department of Energy Sustainable Aviation Fuel Grand Challenge: https://www.energy.gov/eere/bioenergy/synthetic-aviation-fuel-grand-challenge
References:
- “Comparative Economic Analysis Between Bioenergy and Forage Types of Switchgrass for Sustainable Biofuel Feedstock Production: A Data Envelopment Analysis and Cost–Benefit Analysis Approach,” GCB Bioenergy, DOI: 10.1111/gcbb.70020
- “Field-Scale Evaluation of Ecosystem Service Benefits of Bioenergy Switchgrass,” Journal of Environmental Quality, DOI: 10.1002/jeq2.70025
Image Credits: University of Illinois Urbana-Champaign
Keywords: Switchgrass, Sustainable Aviation Fuel, Bioenergy Feedstock, Ecosystem Services, Greenhouse Gas Emissions, Nitrogen Fertilizer, Marginal Land, Biomass Production, Carbon Sequestration, Bioeconomy, Agricultural Sustainability, Renewable Energy
