As the global population swells, boosting the demand for both food and energy, land management has never been more important. Now, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are conducting pivotal research that will help keep soil healthy now and into the future.
There are more than 2 million farms in the United States alone with more than 90 million acres planted for corn. The national statistics reflect a global phenomenon: Corn comprises 13 percent of the world’s arable land.
Scientists have long known that corn residue or stover — meaning the aboveground portions of the corn plant remaining after harvest — plays a critical role in soil health.
“With so much of the earth’s land devoted to farming, it’s critical that we develop best practices to make sure we don’t exhaust this finite resource.” — Hui Xu, environmental analyst at the Systems Assessment Center in Argonne’s Energy Systems division
Corn stover is mostly left on the field either in its entirety or in a lesser amount, depending on the farmer’s practice and soil type.
It serves many critical functions: It protects the surface of the soil by improving soil structural stability and reducing soil erosion, maintains agronomic productivity by replenishing soil organic matter, and conserves soil moisture to facilitate crop growth.
Corn stover is a promising biofuel feedstock. The key question is whether corn stover removal may affect soil organic carbon (SOC) and soil health.
Researchers, aware of the problem, have been studying it for years, but their findings have varied. While excessive stover removal is not a preferred practice, leaving too much corn stover can also cause problems like harbor diseases, tie up nitrogen in the soil, and impede soil warm-up which is important for planting in the spring. This is why it is beneficial to leave some corn stover on the fields but also to collect the excess.
Scientists at Argonne, who also had been examining the issue, led a pioneering collaboration to screen 3,380 papers published between 1990 and 2018 to quantify the overall response of soil carbon to stover removal and to identify key drivers that can help with maintaining soil health.
They collected and analyzed 409 data points from 74 stover harvest experiments sites around the world.
Teamed up with researchers from United States Department of Agriculture and universities, they came to important conclusions that could help farmers manage their fields in a sustainable way.
“We wanted to complete a systematic assessment to address these concerns so we could provide suggestions for relevant stakeholders and industrial leaders,” said Hui Xu, environmental analyst at the Systems Assessment Center in Argonne’s Energy Systems division. “With so much of the earth’s land devoted to farming, it’s critical that we develop best practices to make sure we don’t exhaust this finite resource.”
This type of analysis has already improved scientists’ understanding of SOC implications for bioenergy production.
While many believed that stover removal may reduce SOC, this study showed that careful stover removal could maintain or even marginally increase SOC stock.
Findings from this study can serve as inputs to a suite of models designed to evaluate a critical issue regarding cellulosic feedstocks production including crop residue, dedicated energy crops, and forest residues.
The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation Model or GREET, provides a transparent platform from which energy and vehicle producers, researchers, and regulators can evaluate vehicle technologies and energy systems.
Several Argonne scientists helped develop GREET, which is used by industry, researchers, and regulators to evaluate the energy and environmental footprint of biofuels. This new study only adds to GREET’s effectiveness.
“Every piece of new information we glean from our research bolsters GREET and reduces uncertainty about the environmental effects of biofuels,” said Michael Wang, original developer of the GREET model and the Manager of the Systems Assessment Center at Argonne. “These are living documents. We update the GREET model annually based on creditable new data.”
The research was supported by DOE’s Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office.
The Office of Energy Efficiency and Renewable Energy supports early-stage research and development of energy efficiency and renewable energy technologies to strengthen U.S. economic growth, energy security, and environmental quality.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.
The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science.