Weeds in research field

BLOOMINGTON, Ill. — Bryan Young prefers using tillage and not cover crops.

“Tillage opens the territory so weeds can invade,” he says.

He also plants in 30-inch rows so the crop canopy doesn’t overshadow growing weeds.

“I have a good stand of weeds,” he said proudly.

Farmers attending the Conservation Cropping 2020 seminar here Jan. 22 gave him a funny look.

“I study weed management,” explained Young, a professor of weed science in the botany and plant pathology department at Purdue University.

His goal is to see how the weeds grow and react to herbicides. He earned his PhD specializing in weed science from the University of Illinois, and has researched and taught on the topic for more than 20 years.

Young usually focuses on herbicide application technology and herbicide resistance in weeds. But, in speaking to central Illinois farmers at the conservation cropping event, he broadened his approach to include practices that reduce weeds.

“Illinois leads Indiana in herbicide-resistant weeds,” said Young, who is well acquainted with the weeds in both states. “There’s no doubt weeds are winning.”

Often farmers think about the long-term benefits of planting cover crops, but don’t usually think of the immediate return with weed management. The focus of weed control is usually about “this year,” he said.

Cover crops have some natural weed suppressant factors, he said, citing cereal rye as an example. A good stand of cover crops, as opposed to bare ground, will contribute to weed control. and, Young said an increased biomass created by not killing the cover crop as soon as possible can improve weed control further.

In the field

Rick Clark, a fifth-generation farmer who farms on both sides of the border with Illinois, near Williamsport, Indiana, is a strong believer in the many benefits of cover crops, including their weed controlling powers.

Clark prefers to give the cover crops a good run and doesn’t burn them off with herbicides. He plants his corn and soybeans into green cover crops.

Contrary to Young’s recipe to get a good weed stand, Clark doesn’t clear the soil with tillage to give weeds bare ground to start. Clark has no-tilled soybeans for 15 years and corn for 10 years. He added cover crops to his system a decade ago and has been farming “green” for eight years, planting his corn directly into a green cover crop.

Instead of using chemicals to kill his cover crops, he roll-crimps it after the corn is planted and saves the cost of burn down herbicides. He lets cover crops grow further into the season and they sequester more nutrients, he said.

Clark plants all his beans before corn.

“I plant corn after Mother’s Day in May — not in April,” he said.

This allows him to take advantage of nutrients and allows for better weed and erosion control and increased biomass.

He said “soil health” drives his system.

As for cover crop choice, he said cereal rye and soybeans go together like “bread and honey.”

Cereal rye can be used with corn but will likely require more in-season nitrogen. He prefers diversification with his cover crop, which he tries to plant before Oct. 1.

His choices includes sorghum Sudangrass, oats and radish with cereal rye. He has other specific cover crop recipes he follows.

By the numbers

Data is critical to what we do, Clark said.

“Our ROI (return on investment) is some of the best we’ve seen on the farm in a long time,” he said. “We strive to be low cost on inputs with yields going up.”

As part of his system, he shortens the relative maturity of the corn or soybean crop to get the cover crop planted. For corn maturity, instead of 110 to 115 days for his area, he will grow a 99- to 106-day maturity. He said seed companies are doing more research and offering more options for shorter maturity varieties.

He aims to get his crops harvested and cover crops for corn planted by Sept. 15. However, in 2019, it was simply too wet to follow normal procedures. His harvest wasn’t complete until Dec. 2. Instead they flew on 1,500 acres of cereal rye.

Clark said they are probably leaving some yield on the table with shorter season varieties and hybrids, but he believes it’s worth it.

“Yield is not my driving force. It’s about ROI, not yield.” he said. “I’m good with 160 bu./acre corn.”

While his yields may average lower than in a conventional system that relies on chemicals for weed control and such, he said they are less variable.

“We are going to have some weeds in our system. If you can’t farm with some weeds, you won’t like this system,” he said.

For anyone considering a system like his, Clark says “start easy. Don’t get over your head.” He urges farmers not to throw up their hands and give up if they have one failure.

As for the beginning cover crop grower, he suggests starting with a crop that winter kills, so there isn’t the added concern of killing the cover crop before planting the first year.

He also encourages educating landlords. He said if you explain your plans, they are often supportive.

“Keep everyone in the loop,” Clark said.

Other tips he offers include:

  • Don’t get hung up on yield.
  • Be patient. Soil takes about three years to see improvements.
  • Park the planter if it’s not fit.
  • Don’t plant corn in April (wait until you have maximized what the cover crop is doing for you).
  • Soil test every other year to follow trends of P and K.
  • Take advantage of the resources for improving soil health.

Phyllis Coulter is Northern Illinois field editor, writing for Illinois Farmer Today, Iowa Farmer Today and Missouri Farmer Today.