Baking plains

The United States is pivotal to the global food supply. It provides around half the world's corn exports and nearly a third of wheat exports.

When the 2010 Russian heat wave hit the world's fifth largest grain producer it sent international prices soaring. A similar event in the US would be catastrophic.

For many years, farmers in the Midwest of America have been exposed to warmer springs and more humid summers. While shifting weather patterns have to some extent helped to boost crop yields, they have also heralded trouble ahead.

Scientists are warning farmers to brace themselves for more frequent and intense rainstorms - particularly in the spring when their soil and newly planted crops are at their most vulnerable.

"One of the most robust changes over the last 40 years has been the increase in the frequency of extreme precipitation events," Iowa State University climatologist Gene Takle told Deutsche Welle. "For instance, we see lot of 5-inch (12.7 cm) rains now."

That's bad news in a region where the soils can only absorb 1.25 inches from sudden downpours. Instead of soaking into the ground, the excess water runs across the landscape causing erosion and leeching away important nutrients like nitrogen and phosphorous.

Double whammy

Rainy weather can bring more headaches to farmers than just washing away soil.

Moisture in the air in Iowa and the surrounding region has increased 13 percent over the past 30 years. Greater nighttime humidity means dew stays on crops longer.

"It comes earlier in the evening and lasts longer in the morning," Takle said. "And that creates more favorable conditions for pests, pathogens, molds, fungus, toxins and so on."

US Department of Agriculture (USDA) Laboratory Director and Supervisory Plant Physiologist Jerry Hatfield told Deutsche Welle that plants exposed to both meteorological impacts and pest plagues are getting a "double whammy."

Gray leaf spot, white mold, sudden death syndrome, mycotoxin infestations, stem rust, soybean mosaic virus and crazy top and common smut are just a few of the exotic crop diseases that have moved into the Midwest as a result of warmer, wetter weather, he says.

Flying 'hypodermic needles'

Iowa State University entomologist Matt O'Neal says warm weather currents might even be helping to transport insects more effectively. He is researching the phenomenon as a part of a USDA-funded climate change project in which nine US universities are involved.

As the scientist explained to Deutsche Welle, insects fly straight up in search of food and habitat, and get sucked into weather patterns.

"The currents pull them up into atmosphere and get them into the jet stream, and they use that to get far, far away," he said, adding that they eventually get rained out of the sky somewhere completely different. "So migration over great distances can be facilitated by weather events."

Infestations of these minuscule aphids can literally suck the life out of crop plants, but the damage doesn't stop there.

O'Neal describes the tiny creatures as "flying dirty hypodermic needles with piercing sucking mouth parts" that enable them to pick up a virus from one infected plant and spread it to another.

Adapting is everything

With these challenges in mind, some Midwestern farmers are already adopting techniques to make their farms – and soil – more resilient.

Dick Sloan, an Iowa farmer, recently harvested the corn from his 320 acre field, but this time left his land covered with curving rows of golden stalks.

Instead of stripping his field bare and turning the soil over, he intentionally left behind plant matter and its roots to keep the soil and its nutrients in place.

"If you add organic matter to your soil, you're adding water-holding capacity to your soil, so you're making it less susceptible to erosion," he said.

In an effort to protect his fields from extreme rainstorms, Sloan also uses grass filter strips designed to slow water-run off.

In a soybean field at another of his farms, he is trying another experiment: Tiny green grass-like leaves are peeking up between the already-harvested soybean plants.

"The rye is this little grass," he told Deutsche Welle. "It will overwinter. The snow lands on it, it'll go dormant, it'll be green next spring and grow. Then I'll spray with herbicide."

Sloan will then plant his corn directly into the stubble, but the rye will have served its function. He says the soil is most vulnerable in the spring, when the heavy rains come before the corn crop has had a chance to take root. This time around the rye will help hold the soil down.

Green shoots

Sloan isn't the only farmer concerned about increasingly extreme weather conditions.

Cover crops like these, and other techniques like reduced- or no-till farming, are gradually gaining popularity in the region. Seed-growers have reported an increase in sales of winter rye, and airplane pilots are learning how to spread the crop.

A recent survey of more than a thousand Iowa farmers found that two-thirds believe climate change is real. And 60 percent feel they should take additional steps to protect their soil.

Climatologist Gene Takle is confident that farmers will find ways to move with the times.

"Farmers adapt to everything, whether it's new pests, new markets, rising fuel prices, they have just over years learned to adapt, and climate change is nothing new for them," he said.

Reporter: Kathleen Masterson
Editor: Nathan Witkop