Challenging cover crop beliefs
Delaware County farmer Kevin Glanz is challenging research studies and squashing the popular belief that planting a cereal rye cover crop ahead of corn hurts yields.
Over the past decade, Glanz has developed a nutrient management system that allows him to successfully use cereal rye ahead of both corn and soybeans.
Many agronomists say cereal rye residue delays soil warming and drying, causing less favorable conditions for corn growth.
“I challenge that,” said Glanz. “It’s more of a nitrogen management situation.”
Glanz says he manages nitrogen closely. “You’ve got to have nitrogen at planting — not pre-plant anhydrous or a post-plant application. It’s got to be there at planting,” he says.
Glanz terminates cereal rye three to five days before planting his non-GMO corn. “I plant when it’s still green, but it’s on its way to brown,” he said.
He applies about 17.5 gallons of UAN 28% in a band 2 inches off the row on top of the ground — which equates to about 52 units of nitrogen at planting. He also incorporates a nitrogen stabilizer and applies boron and zinc for micronutrients.
“Cereal rye ties up about 25 to 30 units of N in the spring,” said Glanz. “It’s important to replace that with the planter. I have not had any problems with nitrogen deficiency in my early growth corn.”
In fact, in the 10 years since Glanz began using cover crops on all his acres, corn yields have increased 40 to 50 bushels per acre on his poorest yielding acres.
Glanz says his system has also helped him reduce input costs. “I started cutting back about 10 units of nitrogen every year,” he said.
More specifically, Glanz says he’s gone from using about 1.2 units of nitrogen per bushel of corn raised to about 0.7 units of nitrogen per bushel raised. “It’s due to all of the good things going on in the soil,” he said. “It’s not an overnight success. You’ve got to commit to it and don’t look back.”
Compared to planting corn into rye, it is more widely accepted to plant soybeans into a green cover crop. Glanz typically plants his beans into cereal rye in late April and terminates his rye in mid-May, but this year he sprayed the rye in late May when it was above knee high.
This created a thick mat of residue that resulted in some very good weed control. “There are no failures in no-till or cover crop practices, just unexpected results,” said Glanz.
On his home farm, Glanz didn’t need to spray a second pass for weeds on 125 acres.
“I sprayed for waterhemp on some of my other bean acres, but the rye mat laid down so nicely on my farm that there were no weeds to spray,” he said. “These are the types of things I’ve been working for all these years. This is how you make cover crops pay.”
Before starting a cover crop program, Glanz recommends asking yourself what you hope to get out of it. “Your end goal will dictate your beginning. What are your goals for the cover crops?” he asks. “This is another crop that needs to be managed.”
The key to successfully incorporating cover crops into the crop rotation is to treat it with the same level of consideration as the primary crop, says Mike Henderson, state agronomist for USDA’s Natural Resources Conservation Service (NRCS) in Iowa. “Kevin does a great job treating the cover crop as a productive part of the crop rotation,” says Henderson. “He allows the cover crop to grow sufficiently in the spring to develop extensive roots to improve soil structure and prime the soil biology as well as good top growth to provide soil cover.”
Paying their way
Reducing fuel consumption is another way Glanz is making cover crops pay for themselves. He uses about 4 gallons per acre throughout the entire year — compared to about 15 to 20 gallons per acre for farmers who use tillage. “I take that cost savings and put it toward cover crops,” he said. “The whole idea is to reduce expenses.”
Glanz says it’s important to closely manage and monitor how fields respond to your nutrient management program. “It has helped me take steps, year-by-year, to build a cover crop program that pays me back,” he said.
Glanz is adamant his type of system can work on every farm. “I’m not different than anyone else. It just takes a different thought process,” he said. “We’re so stuck in this tillage thought process. I firmly believe tillage is hereditary.”
For more information about conservation practices and programs to treat natural resource concerns on your land, contact your local NRCS office or visit www.ia.nrcs.usda.gov.
Johnson is state public affairs specialist at USDA-Natural Resources Conservation Service.
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