The U.S. Department of Agriculture (USDA) recently announced a US$500 million investment to expand domestic mineral fertilizer production. While this funding aims to boost local manufacturing, environmental groups argue that the administration should focus on regenerative solutions like legume cover crops to fundamentally reduce the nation’s reliance on synthetic inputs.
The USDA states the move will “improve supply chain resilience.” By increasing domestic manufacturing capacity, the agency hopes to shield American farmers from the extreme price volatility and geopolitical supply shocks that have plagued global fertilizer markets in recent years.
But domestic fertilizer production heavily relies on fossil fuels. Environmental conservation groups like the Union of Concerned Scientists (UCS) and Natural Resources Defense Council (NRDC) argue that American agriculture can benefit more from incentivizing the adoption of regenerative practices like cover cropping rather than fertilizer expansion.
According to the UCS, U.S. farmers apply 30 to 50 percent more nitrogen fertilizer than their crops can effectively absorb. A recent UCS report notes that this overapplication results in substantial environmental, economic, and public health-related costs—particularly in the U.S. Corn Belt.
“When nitrogen runs off into water bodies, it creates algal blooms…algae multiply very quickly in the presence of nitrogen and use up a lot of the water’s dissolved oxygen, which can then create low oxygen zones, also called dead zones,” Omanjana Goswami, lead author of the UCS report, tells Food Tank.
Besides impacting aquatic ecosystems, soil nitrogen can break down into nitrous oxide, a super-pollutant 270 times more powerful than carbon dioxide in trapping heat. Soil nitrification is currently the leading cause of nitrous oxide emissions in the U.S., and Goswami notes that agriculture is the world’s largest unmitigated source of nitrous oxide pollution.
“We’ve seen that overall, about one-third of input costs for corn farmers are budgeted towards fertilizer. So, that’s about 33 percent at a bare minimum of what farmers spend on growing,” Goswami tells Food Tank.
Across the country, farmers are “dramatically cutting nitrogen pollution without sacrificing productivity,” states a recent report by the NRDC. This can be achieved by avoiding overapplication of fertilizers and adopting practices such as adaptive nitrogen management, cover cropping, edge-of-field pollution control, and diverse crop rotation.
The UCS and NRDC hope to see more producers move away from carbon-intensive practices, but economic uncertainty makes shifting a risky move.
“Farmers [are] already operating on very thin margins; [they] need to be getting very high yields to make a profit,” William Burke—an agricultural economist at the University of Maryland Eastern Shore—tells Food Tank.
“From a public good perspective, research into green ammonia and phosphorus recovery from waste streams—that’s where the structural changes are going to come from, where you can realistically think about decoupling our fertilizer that we use and our food markets from fossil fuel markets,” explains Burke. These emerging technologies provide pathways toward long-term fertilizer infrastructure sustainability.
But nutrient management strategies like legume cover crops offer a more immediate pathway to separating our agricultural systems from fossil-fuel dependencies. Mark Peoples, agriculture and food scientist at Commonwealth Scientific and Industrial Research Organisation, notes that integrating legumes into cereal rotations naturally enhances soil structure and improves nutrient availability. “The inclusion of legumes in a cropping sequence generally results in greater microbial biomass, activity and diversity in soils,” Peoples tells Food Tank.
Nitrous oxide emissions tend to be lower from legumes compared to nitrogen-fertilized cereal crop systems as well. Properly managed systems “generally have a lower risk of leaching or runoff,” explains Peoples.
The UCS directly advocates for greater crop diversification through the USDA Environmental Quality Incentives Program. “We need to diversify farming operations by moving away from corn-and-soy monoculture and toward incentivizing best practices instead of maximum production of commodity crops,” Goswami notes in the report.
The UCS and NRDC suggest that expanding federal conservation program funding from the USDA can encourage crop diversification and incentivize resilient practices. “Building cover crops [and] tree cover, diversified cropping systems all help farmers move away from that fertilizer treadmill,” Goswami tells Food Tank.
Articles like the one you just read are made possible through the generosity of Food Tank members. Can we please count on you to be part of our growing movement? Become a member today by clicking here.
Photo courtesy of Sam McCool, Pexels
