September 21, 2023

Corn Belt geography built for agriculture

BLOOMINGTON, Ill. — The geography of Illinois predestined the state to be an area for growing corn and soybean crops.

“There is not another place on earth that comes close to matching what we do throughout the Corn Belt of the U.S. and because of that we are watched very carefully by the rest of the world,” said Eric Snodgrass, science fellow and principal atmospheric scientist for Nutrien Ag Solutions.

“Looking at the corn production per county, McLean County is the biggest producing and highest yielding and I have friends all over the world that trade grain and they know where McLean, Champaign. La Salle and Sangamon counties are,” said Snodgrass during a presentation at the Illinois Society of Professional Farm Managers and Rural Appraisers annual meeting.

“Almost every time it precipitates here, a day or two before the moisture evaporated off the Gulf of Mexico,” he speaker said.

“We have mountain chains on the east and west so moisture can be transported from the gulf to provide rain right over some the most productive ground on the face of the earth.”

In addition, Illinois farmers have access to the Mississippi River and its tributaries.

“We have more flat, navigable waters than the rest of the world combined,” Snodgrass said. “So, we’re built for agriculture and set up to grow what we grow.”

One of the biggest sources of loss in corn yield each year is weather.

“There is 600 bushel per acre potential in that bag of seed,” Snodgrass said. “The moment you tear that bag open, you start to lose that potential.”

There is a lot of corn yield variability in different parts of the United States.

“The south and southeast have too hot daytime and overnight temperatures along with too much moisture that produces issues with fungus,” Snodgrass said.

“North Dakota and South Dakota have a compacted growing season and their climate is susceptible to drought and flooding.”

In the strip in the middle — from southern Minnesota to Iowa, Illinois and including southern Wisconsin, Indiana, Ohio and Michigan, the soils are deep enough to hang onto moisture so when there are dry times there is enough moisture in the profile for the crops.

“We have a growing season with over 3,000 GDDs in a typical year and we typically get 30 to 50 inches of rain,” Snodgrass said. “So, the sweet spot is in the middle of Illinois and Iowa.”

Looking at Illinois minimum and maximum temperatures from June to August, Snodgrass said, the maximum temperature trend is flat.

“But over the last 40 years, we’re seeing an increase 2 to 2.5 degrees in overnight low temperatures,” he said.

“That has expanded our frost-free season by about nine days,” he said. “And since the amount of water in the atmosphere is controlled by temperature, the warmer the atmosphere, the more water vapor there can be in it.”

One of the biggest advantages for Illinois over the last 30 to 50 years is the increase in the total amount of moisture in the atmosphere.

“Since 1970, we’ve seen a 15% increase in precipitable water and a 6% increase in relative humidity,” Snodgrass said. “That extra moisture is coming from what we do as an industry.”

The main purpose of corn and soybean plants is to reproduce and to do that it requires water, sunlight and nutrients.

“That water is pulled out of the ground and transpired through the leaves to facilitate the photosynthesis process so corn and soybeans take water from the ground and put it in the atmosphere,” Snodgrass said.

“Since 1970, the plants are more and more productive so we’re putting more water vapor into the lower atmosphere which is recycled and used for thunderstorm development,” he said.

“Over the last 40-plus years, there has been a 5-inch increase in total precipitation in Illinois,” he said.

“Going back to 1981, we’ve doubled the frequency of heavy rainfall events that have been 2 inches or more in Illinois and that has been a consistent trend almost everywhere east of the Rocky Mountains.”

However, the dry conditions that caused problems on the Mississippi River in 2022 have not completely gone away.

“We have not fully returned moisture to the subsurface soil moisture at 40 inches,” Snodgrass said.

“Normally we do that in March, April and early May, but if we don’t do that, there will be issues for us to be vulnerable to drought in 2023,” he said. “But I think there will be a recharging of subsurface water.”

For the past three years La Niña has impacted the weather in the Midwest, Snodgrass said, but it is finally leaving.

“We probably won’t make it El Niño fully by summer,” Snodgrass said.

“During El Niño events, the westerly winds tend to have momentum and the faster they move the greater chances of new systems rolling off the Rocky Mountains,” he said.

“Those new systems draw moisture from the Gulf of Mexico and give us the routine rain we need.”

U.S. farmers will continue to face competition in the soybean market from Brazilian farmers.

“This year, Brazil put into production one-fifth of an Illinois soybean crop that wasn’t there last year,” Snodgrass said. “And they have 400 million acres of pasture that could be converted to farmland.”

However, the challenge in Brazil is transporting crops.

“Without rivers to move stuff around, they have issues with getting goods to places,” Snodgrass said. “Their flooding rains which are making massive yields also slow down their ability to move the crop.”

Martha Blum

Martha Blum

Field Editor