Getting to roots of plow pan problems

BLOOMINGTON, Ill. — When Ralph Upton Jr. started working on his family’s farm full time in 1964, he did what everyone else was doing — plowing every year.

He recalled the year he was done plowing and a 5-inch rain hit Hamilton County. The soil erosion was obvious. He made a commitment to never plow that field again.

Those early experiences led Upton to question the status quo and look for better ways to farm while improving the soil.

The Springerton-area farmer’s efforts and commitments to on-farm conservation were recognized when he received the Illinois Corn Growers Association’s Mike Plumer Environmental Award at the group’s annual meeting Nov. 21.

“It is my honor to present Mr. Upton the Mike Plumer Environmental Award,” said Matt Rush, ICGA president and Fairfield farmer.

“Junior Upton is a conservation expert in southern Illinois. He has tried many things, been successful and failed and is willing to share all that knowledge with the farmers in our region that also have poorer soils and suffer with similar problems. Junior Upton is a model for conservation adoption and education.”

While no-till was already regular part of Upton’s farming operation, his initial conversations about cover crops were sparked when he attended a conservation farm tour.

He has since worked closely with the Hamilton County Soil and Water Conservation District, University of Illinois Extension and the U.S. Department of Agriculture’s Natural Resources Conservation Service.

Upton and Plumer first met in the early 1980s and Plumer’s expertise in soil conservation, no-till and cover crop management was known well beyond Midwest farm fields.

After his retirement, Plumer continued helping farmers understand and implement conservation practices until his death in 2017.

On-Farm Research

Upton’s curiosity led to a multiyear research project with Plumer.

“The type of ground we farm is very susceptible to dry weather. The other thing was, if you farm some old pasture ground or where the old home place was, that crop was always better. So, why? Then you’d put the pasture ground into production and after two or three years it would be down to what conventional ground was,” Upton said.

“We wanted to try to get that yield back to what it was when it went from pasture ground into production.

“Corn in dry weather can get nearly zero yields or maybe 45 bushels to the acre and I had that one place in the field that wasn’t very big, but the crop would always be good. It may be 125 bushels in dry weather and you’d get five steps away from it and it’d be 45 bushels.

“So, we went out with a backhoe and dug an 80-foot long trench and 3-foot deep through that area of the field to see what was going on.”

U of I experts, including Plumer, were there to help determine the cause of the wide yield variations.

The dig easily revealed the soil in the low productive area was a plow pan, while the high productive soil had no plow plan and the moisture went through the soil profile.

A plow pan is a subsurface horizon or soil layer having a high bulk density and a lower total porosity than the soil directly above or below it as a result of pressure applied by normal tillage operations, such as plows, discs and other tillage implements.

“The roots were growing beyond the plow pan. So, what do you do to improve that? You could rip it and then three or four years later it would be back to the same,” Upton said. “I could not find any information about somebody who has planted a cover crop and did no-till.”

With the help of Plumer and others from the U of I and NRCS, a Sustainable Agriculture Research and Education grant was awarded for a long-term study on no-till and cover crops.

Plumer would then compile 10 years of data from Upton’s farm on soil improvements, yield increases and other accomplishments, changes and lessons.

The study that began in the early 1990s incorporated various cover crops for comparison, and then in 1997, the Oregon Ryegrass Growers Seed Commission wanted to include annual ryegrass cover crops in the trials.

“A farmer from the state of Oregon came by. He was with a group who had been at a farm show and wanted to see the ryegrass. It was in February and the ryegrass was about 3 inches tall,” Upton said.

“We could see the cover crop, but we wanted to see what was going below ground. I got a shovel. Those ryegrass roots went down 2 feet. What is odd about it and what we found out is ryegrass is the only plant that can grow through the plow pan.”

University of Kentucky researcher Lloyd Murdoch got involved in the project. He was studying plow pans and saw one of the Plumer’s articles on the subject and contacted Plumer to meet at the Upton’s field.

“When we dug, you could see from using the cover crops that the darker soil was moving down and was a different color,” Murdoch wrote at the time.

“The corn roots are now growing 5 feet deep into the soil. The cover crop has broken up all of the plow pan and allowed those roots to go down,” Upton said. “In the drought of 2012, we had 3 feet of dry soil under the corn and our roots went down 5 1/2 feet to moisture.”

Upton also noted improved the organic matter along with eliminating the plow pan.

“How this all comes about is you plant a cover crop in the fall. The ground gets wet in the winter. So, that cover crop is shoving that root down,” he explained.

“Another thing that’s amazing is we’ll have 10 degrees or 10 below zero, that root still grows underground. We would do a soil probe in December and the root would be maybe 18 inches deep. Then we’d take another sample in April and it would be 4- or 5-foot deep.

“I’m always looking for ways to solve problems and this really works.”