MINNEAPOLIS – Cover crops, which help control water pollution from agricultural runoff, remain a little-used tool on Midwestern farmlands, despite nearly 100 years of science showing their value, according to a new study from the working group on the environment. The EWG said that while cover crops can offer huge conservation benefits, their potential to meaningfully solve the climate crisis is questionable.
According to EWG’s geospatial analysis, in 2019, only one in 20 hectares of corn and soybeans in Illinois, Indiana, Iowa and Minnesota – 3.2 million out of 68 million in total – was protected by planting cover crops, a simple conservation practice involving other vegetation that holds the soil in place and absorbs unused fertilizer.
“Scientists have known from the Dust Bowl how valuable cover crops are in protecting water, soil and air quality,” said Soren Rundquist, EWG’s director of spatial analysis and main author of the report. “Cover crops can also mitigate some of the effects of severe storms associated with the accelerating climate crisis. But farmers just aren’t planting them on enough acres to generate these benefits in any meaningful way.
EWG has analyzed cover crop use in Illinois, Iowa, and Indiana every two years since 2015. From 2015 to 2017, cover crop use in all three states increased, but their implementation slowed significantly between 2017 and 2019. Minnesota was a new addition to the newly released 2019 study.
The most recent analysis shows that cover crops are still only used on a small portion of farmland in all four states. Indiana had the highest percentage of cover crop area (9.2 percent), followed by Iowa (4.2 percent), Illinois (3.9 percent) and Minnesota (3.8 percent).
The Ministry of Agriculture and industry interest groups recently proposed that farmers be paid to plant cover crops to capture carbon as a strategy to tackle the climate crisis.
By reducing flooding and soil loss, cover crops can help protect soil, water, and people from dangerous weather conditions caused by the climate emergency. But they have limited potential to deliver the large, reliable and rapid emission reductions urgently needed to slow climate change.
A 2018 study by dozens of researchers from nonprofits, universities and government agencies estimated that planting cover crops on 217 million acres of cropland – 14 times USDA estimates of nationally planted cover crops – could store enough carbon to offset just 1.6 percent of all net U.S. emissions.
Other research suggests that any carbon capture benefits of cover crops are only effective as long as the land remains covered and not tilled. Yet the EWG study found that in the three states studied for three consecutive years, only one in six acres was protected by cover crops in 2017 and 2019, and only one in 17 acres was protected in 2015, 2017 and 2019.
Meanwhile, the scale of use of cover crops remains considerably lower than what is needed to dramatically reduce fertilizer runoff and soil loss – the causes of contamination of tap water, epidemics of toxic algae and the annual Gulf of Mexico “dead zone”, plus what some scientists believe is the increasing likelihood of a new Dust Bowl.
“To protect the environment and human health, the federal government should increase funding for conservation programs to get cover crops on many more acres as quickly as possible,” Rundquist said. “But even widespread planting of cover crops simply won’t solve the climate crisis. “
Most conservation funds are allocated through the federal Farm Bill, an omnibus law that is reauthorized about every five years. A new agricultural law could be passed as early as 2022.
The Environmental Working Group is a non-profit, non-partisan organization that empowers people to live healthier lives in a healthier environment. Through unique research, advocacy and education tools, EWG drives consumer choice and civic action. Visit www.ewg.org for more information.