Nearly 40 percent of the world’s land is devoted to farming, a figure that will need to increase dramatically as the Earth’s population grows from its current count of 7.5 billion to nearly 10 billion by 2050.
Humans have been managing crops for thousands of years — you would think we would have farming mastered. Yet some current agricultural practices remain remarkably inefficient, wasting precious resources and polluting both land and sea.
A team of scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory has been working for nearly a decade to control some of the more environmentally harmful side effects of modern farming.
“We’re coming up with ways to use the landscape better so that we can increase the sustainability of everything we grow, including bioenergy and food crops,” said Cristina Negri, director of Argonne’s Environmental Science Division. “Land and water are in limited supply, so we have to use these resources in the smartest and least harmful ways possible.”
Negri’s team is investigating the use of bioenergy buffers — like perennial biomass crops, such as willow and native prairie grasses — in agricultural lands to reduce the impact of soil nutrients on water quality.
Excess nutrients — namely nitrates — in farmed soil can leach into surface water and shallow groundwater, increasing the cost to treat drinking water.
Among the more dramatic impacts is the eutrophication (e.g., excessive richness in nutrients) of surface water, as seen in the Gulf of Mexico, where nitrogen runoff has caused harmful algal blooms that eventually lead to massive fish kills.
Primary target areas for the team’s work are those where the bioenergy crops can intercept nutrients in the subsurface and in underproductive soils, where excess fertilizer is more likely to leach.
Buffer placement is also important from a bioenergy production standpoint. Intercepted nutrients are a fertilizer source for willows and enhance biomass production.
A perennial bioenergy crop provides other ecosystem services, as well: essentially eliminating erosion, improving water and air quality and providing additional wildlife habitat. Willows can also be used in the production of biofuels and bioproducts.
Negri, an agronomist and environmental engineer, conceived of the approach and led the project from the start. John Quinn, hydrogeologist in the Water and Aquatic Resources Department at Argonne, currently leads the team’s on-the-ground work.
The Argonne scientists conducted much of their research on a 16-acre corn and soybean field in Fairbury, Ill., about 90 minutes south of the laboratory. They visited the parcel at least biweekly during the growing season to measure crop productivity, nutrient leaching and greenhouse gas emissions.
Their findings can be scaled to larger watersheds through computer modeling.
“This is a complex project that deals with energy, environment, ecosystem services and economics,” Quinn said. “We are trying to determine the difference in nitrate levels in areas where our methods are employed and where they are not. The results have been more than promising.”
The team is currently seeking approval from the Natural Resources Conservation Service, an agency with the U.S. Department of Agriculture, to use bioenergy buffers as a practice for reducing nutrient leaching.
“A lot of the initial work involves site assessment to determine where the willow buffers will have the biggest impact on nitrogen reduction,” explained Colleen Zumpf, a PhD candidate at Argonne and field manager for the project. “The goal is to have deep-rooted willows intercept nutrients, preventing them from further leaching into groundwater or nearby surface water.”
In addition, the willows will uptake those nutrients and enhance biomass production, she said.
While the team’s primary goal to sustainably grow bioenergy crops while reducing pollution is laudable, such an approach must appear financially appealing to farmers for it to take hold.
To that end, they point to several positive side effects that have resulted from their buffer technique. In addition to producing bioenergy feedstock, these new methods reduce greenhouse gas emissions, reduce erosion and sedimentation and enhance pollinator — think bees — habitat.
Jules Cacho, an Argonne postdoctoral appointee working on the project, said he believes farmers are likely to adopt the method if the economics are workable.“If farmers see they are making a profit and are helping the environment, there is nothing to lose,” Cacho said. “The science is already there.”
“If farmers see they are making a profit and are helping the environment, there is nothing to lose. The science is already there.” — Jules Cacho, Argonne postdoctoral appointee
This work is sponsored by DOE’s Bioenergy Technologies Office (BETO).
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.