September 07, 2018

New strategies may help boost corn production for local farmers, while still protecting the environment

by Hannah Erickson

CARBONDALE, Ill. — Reducing nutrient loss in farmland is an important topic for those in the agriculture industry. But while valuable adjustments have been made to preserve water quality and reduce environmental concerns, these practices often reduce production rates for farmers.

That’s why researcher and professor, Amir Sadeghpour is hard at work finding new ways to preserve both the environment and crop production.

Mismanagement of cover crops can reduce corn production

Nutrient losses not only affect the health of the soil, but can also be damaging to water sources. In the last several years, the U.S. Environmental Protection Agency has called for states along the Mississippi River Basin to form a plan to reduce the amount of phosphorus and nitrogen carried in rivers throughout the states and into the Gulf of Mexico.

In compliance with these standards, farmers often use cover crops to keep the nutrients in the soil. A recent practice is to terminate the cover crops late in the season, with the goal of increasing nitrogen uptake that would decrease nitrate leaching and help with preventing nutrient losses through runoff. But while this helps to solve one problem, it contributes to another.

Sadeghpour, assistant professor of plant, soil and agricultural systems at Southern Illinois University Carbondale, has found that this strategy impacts the rate of production for farmers.

“One issue that happens, is such a strategy often reduces the yield of corn,” Sadeghpour said. “A main reason for it could be due to nitrogen immobilization due to late termination of cover crops. Our goal is to assess whether, by splitting nitrogen application rate, we can overcome yield losses and ensure farm profitability and still decrease nitrogen losses.”

While it is important to protect the environment, farmers cannot afford for production to be decreased.

A new method of cover crop planting

In a typical situation, farmers plant cover crops after harvesting the cash crops. Research has shown this nourishes the soil, while also reducing nitrate leaching. But Sadeghpour is experimenting with new equipment that could allow growers to plant cover crops earlier during the cash crop growing season.

Working with Karla Gage, assistant professor of plant, soil and agricultural systems at SIU, the team recently started experimenting with InterSeeder equipment. The goal is to allow farmers to plant both corn and a cover crop at the same time.

“It allows you to go in the corn field and basically plant the cover crops during the corn growing season,” Sadeghpour said. “Usually the corn canopy closes and those cover crops that are established beneath the cover crop go dormant. When the corn matures, the light will penetrate, and you already have a cover crop established.”

Timing is one of the main issues with adding cover crops, Sadeghpour explained.

“A lot of times when we harvest the corn and plant the cover crops, we don’t have enough time to catch the residual nitrogen that is there in the September to December period,” Sadeghpour said.

The goal of this research is to catch that nitrogen after the fall harvest, Sadeghpour said.

With the inter-seeding technique, farmers are able to utilize the benefits of the cover crops, while maintaining their normal crop production rates. This not only has implications for better production, but also manages the environmental issues as well.

Practice may be beneficial for Illinois

This type of inter-seeding is very new for Illinois. While the practice has been implemented in other states such as Pennsylvania, New York, Minnesota and North Dakota, Sadeghpour believes it could be helpful in other regions.

If we can figure out the best times to plant and how to manage the cover crops, this may be a very suitable practice for growers in Illinois, Sadeghpour said.