Drier heat waves threaten crops in Iowa

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IOWA — Jean Eells dug into the earth on her farm after the fall harvest and discovered a problem. It was 2016 and the farmer that rented her land had just left. When she pulled her spade from the ground she noticed the soil was hard and compact, with layers looking  like “thinly stacked dinner plates.”

Healthy soil soaks up and stores more water, helping farmers grow healthy, nutritious and productive crops. But warming temperatures are threatening the productivity of croplands through the Midwest, with new data showing how drought makes corn and soybean crops much more sensitive to heat. 

“I want to make sure that my soils are in good shape, so that I will have a farmer that can make money,” says Eells. “And if my soil is degraded and doesn’t handle the drought, doesn’t handle wet conditions, I’m concerned about that.”

Good soil also helps crops withstand the types of weather extremes that are becoming more common as pollution traps heat. Heat waves, drought and floods will continue to become more intense as temperatures continue to rise. Like Iowans saw this summer, heat waves and drought will collide more often.

Eells said she decided to take a more active role in managing her land before a new tenant farmer took over. She switched to no-till practices and started to plant cover crops, like oat and rapeseed, because they help keep moisture in the soil before the upcoming growing season. 

The U.S. just faced the warmest summer on record, tied with 1936 during the Dust Bowl. And a summer-long drought hit parts of Iowa and other Midwestern states. As drought and extreme heat hit the region more often and with greater intensity, its productive soils are at risk. 

“We can’t till our way out of this,” says Eells. 

The fall after she planted cover crops, Eells noticed her land looked healthier. One sign of this was the earthworms burrowing throughout the soil, which was now loose enough that they had space to move. 

The new research on warming temperatures and drought warns that drier heat waves will reduce harvests, threatening to further narrow farmers’ profit margins. 

Experts say that paying closer attention to soils and improving farming practices like Eells has done on her land in Webster County, will help crops and those that farm them handle the additional stress.

Drier heat waves

In a global study published Monday, scientists at Columbia University showed where drier heat waves will damage major types of crops as temperatures continue to increase. 

The Midwest stood out as an international hotspot, where damage to corn and soybean yields may be upwards of 10 to 20 percent after 2050. Iowa and its economy will experience impacts, given its a top producer of corn and soybeans across the U.S. 

Midwest farmers will likely see conditions that look a lot like Texas currently, says Corey Lesk, a climate scientist at Columbia University and lead author of the study, which was published in the journal Nature Food on Monday

Some counties in the western part of Iowa may suffer financial losses nearing $60 million per year in corn and $30 million per year in soybeans later in the century, according to an analysis of Lesk’s and economic data. 

The timing of these hot droughts will matter. “It’s better to have a drought form early in the season versus the middle of the growing season,” said Justin Glisan, Iowa’s state climatologist. 

Even though Iowa is getting wetter, much of that rainfall is coming in heavy downpours, causing extreme flooding. And intense rainfall in the middle of a drought doesn’t always provide relief. “That rainfall runs off faster than it soaks and so drought acts almost as a concrete barrier,” Glisan said.

And there has been a reduction in rainfall in July, right when it’s getting hotter and corn is maturing, says Glisan.

Less rainfall in July is “a worst-case scenario because corn needs its water in the middle of the growing season,” said Dennis Todey, the director of the U.S. Department of Agriculture’s Midwest Climate Hub, which helps agricultural managers make climate-informed decisions.

If a drought strikes earlier in the summer, as was the case this year, by contrast, it can help with agricultural production by prompting corn and soybean crops to root more deeply in search of moisture. Roots can get up to six feet deep in Iowa, says Todey. Deep roots allow the plant to have more access to water beneath the soil surface, which is better for yields during stressful conditions. 

While Iowa farmers saw some recent relief from rain, much of Iowa is still in a drought and in need of a soil water recharge going into winter. 

There are also considerations when it comes to how crops are bred, says Lesk. It usually takes decades to develop crops. Crops are now being bred for combinations of climate stresses that rarely occurred in previous climates.

Looking to soil as a solution

“Soils are the first line of defense dealing with these issues,” Todey said. Healthy soils can hold a lot more water than unhealthy soils, meaning more productive crops.

Status quo farming won’t work anymore, says Eells. But “farmers are fabulous problem solvers.”

One of the best things that farmers can do to protect their crops is to care for their soils. 

Eells described visual tests that farmers like her use to check the health of their soils. If the soil is healthy it will look like coarse breadcrumbs, while she said unhealthy soil looks like cocoa powder. The coarse grains in healthy soil are filled with carbon and microbes that help “glue” the soil particles together.

Eells started using no-till practices when she noticed her soils were hard and compact. No-till leaves plant material left in the field after harvesting on top of the soil, creating a barrier that helps prevent water loss. 

Tilling also breaks up healthy, coarse soil, releasing the carbon that growing plants put into the soil and killing some of the microbes. When this happens, the soil struggles to hold onto water and crops have less access to water on hot, dry days. 

Eels also began planting oat and rapeseed as cover crops and continues to work on finding the best crops that work for the farm. Cover crops extend living roots out into the soil that help glue the soil particles back together, opening up space for water and air to move. They also keep the microbes alive.

“Cover crops and no-till practices are like insurance for topsoil,” says Eells.

No-till is the most common conservation practice used by farmers in Iowa and its usage is increasing, though 2017 research from Iowa State University showed it was only used on 27 percent of the state’s farmland. Cover crops are only used on 4 percent of the land, the researchers found, while one in five farmers here said they’d be willing to pay a portion of the cost of cover crops on leased land.

Adding another crop to the rotation, especially one that grows early, can change the kinds of microbes living in the soil. New and different crops give them an assorted menu. 

“We have climate change upon us,” she said. “We can’t wait.” 

Investing in the future

Eells teaches conservation practices to fellow women farmers and landowners because she wants to make what? accessible. 

“So often we perpetuate the same style of outreach in conservation and we find that by simply shifting that outreach it makes it accessible and lets women thrive as learners.”

Women are an invisible group in agriculture, she says. Although, in Iowa, women own or co-own nearly 50 percent of all farmland. 

“If we do conservation without them, we are doing it with one arm tied behind our back,” she says. 

She works with organizations like the Women Food and Agriculture Network, or WFAN and participates in a lot of peer-to-peer mentoring circles.

Women are stewardship partners, they don’t just sit back and collect a check, said Eells. When women leave a mentoring circle, the vast majority take action.

“Once they know there is a problem and that other women have solved those problems, they do it,” she said. “They take action.

This story was produced through a partnership between NBC WHO 13 Des Moines and Climate Central, a non-advocacy science and news group.

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

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