Derechos, rare haboob in Iowa raise concerns: Is the Midwest headed to another Dust Bowl?
After a derecho slammed through Iowa two years ago, flattening nearly 4 million acres of corn and soybeans, Jack Boyer discovered something surprising.
His neighbor's 160-acre corn crop was mostly blown down, while his field next door, with many of the same seed varieties, "mostly stood," said Boyer, who farms near Reinbeck in eastern Iowa.
Boyer was able to harvest the field normally. His neighbor faced the painstaking and expensive task of salvaging the fallen ears by running a combine in one direction only, requiring twice as much time and fuel as the harvester circled back around for each run.
Boyer and others believe years of mostly no-till planting and cover crop use helped his corn develop a stronger root system, making it better able to withstand the winds that hit 140 mph in parts of the state.
"With full tillage," the usual process of turning over the soil across an entire field before planting, "the whole plant rotated and went down," Boyer said of his neighbor's corn. "It didn't break off. It just pulled the roots out and came down."
No-till cultivation leaves the soil largely undisturbed.
A growing number of punishing high-wind events have hit Iowa over the past two years: an unprecedented four derechos, one of them accompanied by a massive dust storm called a haboob. It likely was the first in the state since the Dust Bowl days of the 1930s.
Along with more extreme rainstorms as the climate warms — such as the record rainfall that flooded St. Louis on Monday and Tuesday — the increase in high wind events is accelerating soil erosion. Experts are advising farmers to look to methods like Boyer's to protect their precious acreage and guard against a recurrence of the Depression-era disaster.
"We know that soil can move within a field with large rain events. But that's not as immediately visible as wind," said Iowa Agriculture Secretary Mike Naig.
Naig's family farms in northwest Iowa, where growers who experienced the haboob — Arabic for "violent storm" — told him they saw a massive wall of dust blackening the sky.
It also howled through parts of Nebraska, South Dakota and Minnesota, scouring everything in its path.
"Whether it's dirt in a snowbank or a dust storm … I would hope that it would lead some folks to consider what they could be doing to keep more of their soil in place," Naig said.
The challenge Iowa farmers face may be more daunting than officials estimate. A recent study looking at topsoil loss in Iowa and other large corn-growing states found erosion has scraped away topsoil from a third of the region since large-scale farming began roughly 160 years ago.
Soil erosion — totaling 30 million acres , mostly on hills and slopes — costs Iowa and other Midwest farmers nearly $3 billion annually in lost production, according to the report, which chiefly blames tillage for the land's vulnerability.
"Soil erosion rates in the Midwest are occurring at unsustainable levels, and there is not a clear indication that the rates have declined since soil conservation practices and policies were implemented in the wake of the Dust Bowl of the 1930s," University of Massachusetts Amherst scientists reported in their study, which compared topsoil levels today with those in remnants of the original grass prairie, including several in Iowa.
Rick Cruse, an Iowa State University agronomist, said natural processes generate about half a ton of topsoil per acre each year. But the U.S. Department of Agriculture considers 5 tons of soil loss per acre annually tolerable — 10 times more than is replaced, he said.
And with climate change bringing more extreme weather, soil erosion is likely to worsen without increased conservation, experts say.
"Can we continue to do what we've done in the past and meet the nutritional needs and the environmental constraints that we're going to see in the future? I think the answer is no," Cruse said.
Cover crops not only protect fields, but cut fertilizer use as prices spike
Boyer, a retired John Deere engineer, first started growing cover crops a dozen years ago, looking for a way to improve soil health while cultivating seed corn under contract to suppliers.
Back then, "seed corn companies wanted you to turn your soil black," Boyer said. "So you had to use full tillage. And that caused erosion. It also caused degradation in the organic matter in the soils."
His father-in-law, who was born and raised on the farm Boyer and his wife, Marion, now own, used to stop growing seed crops every seven or eight years, shifting to producing commercial corn, which creates more crop residue that contributes to soil health.
Boyer said he hoped not to have to pull out of the seed corn rotation, which "was financially advantageous to me."
So he began testing cover crops, starting with 50 acres. He immediately noticed that the soil more readily absorbed moisture. Then he saw the cover crops helped suppress weeds and boost organic matter — adding to the nitrogen and other nutrients in the topsoil that feed plants.
"After three or four years, I saw improved yields with my commercial corn," said Boyer, who raises crops on about 500 acres. "And I went to 100% cover crops on all my acres."
Boyer has found that the added nitrogen from cover crops has enabled him to cut his commercial fertilizer use by 40%, a reduction that comes as nitrogen, phosphorus and other fertilizer costs have spiked 300% and more.
"It feels pretty good," Boyer said. "Those are checks I'm not writing."
Despite such advantages, farmers like Boyer are the exception in Iowa rather than the rule.
While Iowa farmers are planting nearly 3 million acres in cover crops annually, that amounts to one-tenth of the state's 30 million acres planted with corn and soybeans, Iowa State University data shows.
It's about eight times more than a decade ago, so "we're making progress in terms of getting some cover, getting some residue on top" of the soil to hold it in place, said Naig, the Iowa agriculture secretary.
These days, in addition to about 35% of Iowa farmers practicing no-till planting, 40% use conservation tillage, where about 30% of the soil is still covered with crop residue — corn cobs and stalks or soybean stubble.
About 25% use conventional tillage, plowing through and turning most of the soil.
Craig Cox, the Environmental Working Group's senior adviser on agriculture and environmental policy, said no-till usage is too low to make a significant difference in soil health.
Continued soil loss not only threatens crop yield, but directly impacts Iowa's water quality. About half of Iowa's assessed waterways — 751 rivers, streams, lakes and reservoirs — are considered impaired, based on an Iowa Department of Natural Resources survey. Des Moines Water Works battles high nitrate levels and toxins from harmful algae blooms in the Raccoon and Des Moines rivers, the source of drinking water for 600,000 central Iowa residents.
Using cover crops, no-till planting and other conservation practices improves retention of fertilizers, herbicides and other farm products in the soil, reducing runoff into Iowa's rivers, lakes and streams, Cox said.
Healthier soils also better absorb water, slowing the runoff that contributes to flooding.
With climate change bringing more extreme weather, those conservation practices become even more important.
"There's no evidence of any kind of increase in conservation practices, at the scale and intensity needed, to stand up against more extreme weather that we're facing now," Cox said.
Haboob returns after nine-decade absence
Justin Glisan, Iowa's state climatologist, said Iowa going forward can expect two derechos every two years. The state's seen four in the last two: The Aug. 10, 2020, derecho, which was the most expensive thunderstorm in U.S. history at $12.5 billion; a derecho in December; the May haboob, which also was classified as one; and one in July.
Glisan said haboobs, common in the arid Southwest U.S., are rare in Iowa and the Midwest. Drought in Nebraska, South Dakota and other western states, combined with a late start to planting that left fields with less crop cover than usual in May, contributed to the haboob, he said.
Allan Curtis, a National Weather Service meteorologist in Des Moines, said Iowa hasn't had a haboob since Dust Bowl storms reached the state in the 1930s.
Four large droughts, covering most of a decade, combined with the low crop prices of the Great Depression, prompted farmers to tap marginal land to compensate for lost income, leading to erosion and the massive dust storms.
The state historical society in Minnesota has in its collection a photo of a massive dust cloud descending on Minneapolis in 1938. Cox, a Minnesotan, said one of his grandmothers died from "dust pneumonia" caused by excess exposure to the storms.
Though states like Minnesota and Iowa weren't affected as severely as Kansas, Oklahoma, Texas and New Mexico, where the Dust Bowl was centered, "My mom would tell stories about hanging wet sheets on doors and windows, as a little girl, to try to keep the dust out," he said. "It was just impossible."
Is another Dust Bowl possible as dryness, storms increase?
With extreme drought in Western states, Cox said he could see another Dust Bowl gripping the country.
Already, ranchers in Western states are selling cattle, unable to feed them as pastures burn up and water disappears. And farmers there, facing reduced water availability, are leaving fields fallow as the Colorado River and some aquifers reach historically low levels.
Iowa has struggled with drought as well this year, with nearly 60% the state experiencing abnormally dry or drought conditions. It also experienced moderate to severe drought last year, and though farmers ended up with near-record crops, it was only after getting just enough rain late in the summer to save them.
"They called them million-dollar rains," said Mark Licht, an Iowa State University agronomist.
With critical pollination now occurring in corn and soybean fields, farmers are again praying for rain.
Despite the dryness and the increasing windstorms, Glisan, the state meteorologist, said he doesn't expect to see a return of Dust Bowl conditions.
"We just had a variety of factors that aligned perfectly for that to happen," he said.
He also said the Dust Bowl changed U.S. agriculture, making it more resilient. Farmers in hilly terrain began building terraces and grass waterways to cut erosion and adopted contour plowing, while the federal government supported planting millions of trees as windbreaks.
"From a conservation standpoint, we're in a much different place than we were back in the Dust Bowl," agreed Naig, adding that the Dust Bowl led to "the foundation of modern conservation movement."
'There is a real problem'
Despite such reassurances, Evan Thaler, the lead author of the University of Massachusetts Amherst study, said farmers are losing yields and money with soil erosion — about $3 billion annually.
They try to compensate for the lost fertility with increased fertilizer use. While it's not part of the study, Thaler puts that cost at about $500 million each year.
"Farmers should be worried," said Thaler, much of whose work focused on prairie remnants in Iowa. "They will continue to suffer these economic losses" with continued soil erosion.
"But no-till and cover crops can mitigate these losses," he said.
Boyer, the northeast Iowa farmer who has widely adopted cover crops, said he talks with other growers about his experience. Young farmers tell him they're interested in adopting cover crops, but their fathers or grandfathers are resistant.
"I think it's going to be a generational thing," he said. "Land might have to change hands before things change. … It's going to take time."
Meanwhile, with the University of Massachusetts study showing one-third of Corn Belt farmland devoid of topsoil, "and the potential for increased climate stress, there is a real problem," said Cruse, the ISU agronomist.
Donnelle Eller covers agriculture, the environment and energy for the Register. Reach her at firstname.lastname@example.org or 515-284-8457.