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‘Delay the Burn’ workshops illustrate program’s outline

Managing Editor

GREENSBORO, Md. (May 16, 2017) — Last week wrapped up a series of initial workshops exploring the concept and discussing the benefits of letting cover crops live longer in the field before planting the year’s cash crop.
The “Delay the Burn” workshops held in White Hall, Princess Anne, Chambersburg, Pa., and Greensboro toured demonstration plots in production fields where farmers delayed their herbicide application by at least two weeks than the rest of the field.
The plots are part of a University of Maryland research project through a Northeast Sustainable Agriculture Research and Education grant to examine the benefits and parameters of letting cover crops live longer, planting corn into live cover and mixing cover crop species to improve soil health.
With a strong state incentive program for farmers to use cover crops in their crop rotations, many Maryland farmers terminate the crop in early March with the thinking that advanced cover crop growth would interfere with planting corn and that the cover crop has reached its agronomic benefit.
Nevin Dawson Extension sustainable agriculture coordinator, who’s leading the project said the goal is to get farmers to consider waiting.
Many recent model planters can easily handle up to several additional weeks of grass cover crop growth, he said, and there are several substantial benefits still to be had from as few as two more weeks of growth.
Benefits include moisture retention during dry spells and increases in organic matter, root action, infiltration and the amount of nitrogen retained in the soil profile.
The four farmers are also participating in another multi-year Conservation Innovation Grant funded project evaluating the biomass at various cover crop termination dates.
“That’s a big piece in looking at when the nitrogen becomes available,” said Nate Richards, Extension ag agent in Kent County who is involved with the CIG project.
At the Greensboro workshop, held on the farm of Jim Lewis, Caroline County Extension agriculture agent, attendees walked through the demonstration plot which Lewis said was sprayed on April 29 after corn was planted on April 10. The rest of the field was sprayed in mid-April.
Lewis said an initial concern in the delayed termination plot is if the cover crop plants, extra growth would shade out the corn plants too much and impact the yield, but that won’t be determined until the corn is farther along or harvested.
“There’s people that say that if the corn plant senses something next to it, it won’t but out as big an ear,” said Dr. Ray Weil, University of Maryland professor of environmental science and technology. Weil said he thought the corn had another week before yield would be impacted. “It’s a question of timing on that. It’s a question of whether the corn will be above it” (in a week).
Kent County farmers Tyler Johnson and his son Webb, attended the workshop though they’re early adopters of pushing their cover crop termination later. Tyler said they started experimenting with planting into a live cover crop more than 10 years ago and now all their cover cropped land is delayed in termination. He said the practice has helped them double the level of organic matter in their fields and steadily decrease the amount of fertilizer they apply to the cash crop. He said it’s tough to quantify the agronomic benefits year to year given variable weather and growing conditions but they’re committed to keep doing it.
“We’ve gone full-scale into it,” Tyler said. “It’s a long-term program. Just like farming.”
Webb said it puts more pressure on them to scout their cover crops and an be ready when it’s time to act but sees it as a key part of their operation.
“Timing is crucial,” Webb said. “You’ve got to pay attention to cover crops.”
Dawson referred to an newly-updated Soil Health Card from USDA’s Natural Resource Conservation Service in detailing four key principles of improving soil health. They include minimizing disturbance, maximizing crop diversity, keep living roots in the soil as long as possible and keep the soil covered with residue at all times.
“What we’re looking for in soil health is a low and slow decomposition of organic matter,” Dawson said. Exposing the soil to oxygen through heavy tillage stimulates bacteria in the soil to decompose organic matter faster. As for maintaining residue on the field surface, Dawson called it “soil armor” keeping moisture in the soil longer and adding organic matter.
The soil health card includes a rating system with seven indicators for farmers to evaluate fields to show what aspects of soil health the field is strong in or deficient.
Dawson said demonstration field days will continue as the project progresses to show the benefits of delayed cover crop termination, the next one likely in late summer.