EARLVILLE, Ill. — Carl Zimmerman’s journey into cover crops began several years ago when the family was growing sweet corn for Del Monte.
The crop was harvested at the end of August and early September, and the ground then sat idle until the following spring.
“We’d have weeds pop up and we’d have to spray it with Roundup and 2,4-D to try to keep everything at bay so we didn’t have a seed bank for the next year, or we resorted to doing full tillage on it with a chisel plow, then disking it in the spring and running a field cultivator,” Zimmerman said in a recent Illinois Sustainable Ag Partnership-hosted risk management webinar.
“We wanted to stop the madness. That’s why we started into cover crops.”
The Zimmermans currently farm 1,600 acres in La Salle County, which this year includes a 50/50 split of corn and soybeans. They’ve been no-tilling soybeans for about 15 years and no-tilling corn for about six years.
With a no-till and cover crop system, they were able to minimize their investments into machinery and made some adjustments to their planter to make it work. They use two 180-horsepower four-wheel drive tractors for their operation.
“We drill our cover crops on standing corn stalks after we get done combining. We use that same tractor to run our planter in the fall and spring and we have a 7630 John Deere for the sprayer and we built a roller crimper last year,” he said.
“With the delay in planting we had time, we found an old planter frame, took the row units off and built our own roller crimpers to install on it and rolled approximately 700 acres of rye down and planted our soybeans into it and had very good success with it.”
Zimmerman’s presentation included comparing the costs for a no-till and cover crop system with a conventional tillage operation.
Fuel Costs
In a conventional system, he said a neighboring farmer is burning approximately 2 gallons per acre to pull the tillage tool. He follows that up with a pass with his disk, using up a little over one-half gallon per acre, then field cultivating uses about three-fourths of a gallon per acre.
The conventional farmer uses about two-tenths of a gallon per acre to sidedress his corn.
“He is doing two passes for spraying to our one. We are really working with the cover crops to try to keep our weed at bay and we’ve been able with the right selection of herbicides to get by with one trip, saving one-tenth of a gallon an acre. It doesn’t seem like a lot but at the end of the day you add the numbers up,” Zimmerman explained.
“To put the crop in the neighbor is using 4.1 gallons per acre and we’re using 1.05 gallons per acre to cover the same amount of ground.”
The extra passes in the conventional system for burns about 4,100 gallons of fuel across 1,000 acres compared to the no-till and cover crop combination that uses 1,050 gallons. The cost per acre for conventional is $11.28 per acre for fuel and $2.89 per acre for no-till fuel costs for 1,000 acres.
Fertility Costs
Zimmerman’s fertility program includes soil testing every other year and using that information allows them to utilize variable rate technology across all of their acres, cutting their fertility program in half compared to what others are doing in the area with a general blanket application.
Based on the prices paid this spring, for a conventional two-year spread the cost is $67.50 per acre. The Zimmermans are paying $33.46 per acre over two years as their soil continues to recycle phosphorus and potassium.
“Since using VRT, I’ve got hundreds of acres that haven’t seen a MAP application in over seven years and we’re not seeing it drop off, we’re not mining the soil. We are actually building fertility,” he said.
He typically applies approximately 90 pounds per acre of potash annually and uses about 5 pounds of MAP across his fields in 2- or 3-acre “holes” that need it.
Nitrogen Costs
Nitrogen is another area where savings have been realized by using cover crops.
In conventional systems in Zimmerman’s area, about 180 to 200 pounds of nitrogen is applied, depending on the yield goal.
He does stalks tests annually to determine the nitrogen needs and is also involved with Natural Resources Conservation Service’s Environmental Quality Incentives Program and Conservation Stewardship Program where they recommend 160 pounds of nitrogen per acre on the Zimmerman farmland.
He does not use nitrogen stabilizers and typically splits nitrogen applications with 45 units per acre at planting and sidedresses the remainder.
“The nitrate stalk tests that we pull in the early fall are showing that we’re never running out of nitrogen. I feel like we may be able to even take that number down a little farther and still maintain yields,” Zimmerman said.
He estimated the nitrogen cost for a conventional system using 180 pounds per acre and a stabilizer is $87.35 per acre.
For no-till and cover crops, where 160 pounds were split-applied, the total cost for nitrogen would be $78.95 per acre for an $8.40 per acre cost savings compared to conventional.
Weed Control Costs
In this era of herbicide-resistant weeds, cover crops provide another control tool to control pests such as waterhemp.
As soon as the combine gets through the cornfield, a drill follows to plant about 50 pounds of cereal rye per acre, keeping the soil covered.
“We’re not seeing any issues with waterhemp. The only places where we do have issues are where water comes in from maybe another field or where we’ve had drowned out spots that’s hard to get something established in,” Zimmerman said.
In Zimmerman’s weed management program prior to no-till and cover crops required a minimum of two herbicide applications that included a burndown of Sharpen or Ledger with Roundup with a liquid AMS and drip retardant and at least one post of Roundup for a total cost of $55.25 per acre.
The program he’s been using the last two years along with cereal rye cover crops has included one herbicide application. Last year, he applied Outlook and Roundup.
This year, they used Flexstar, Zidua SC with Powerhouse and MSO at a $34.53 per acre, a savings of $20.72 per acre compared to the no-till without cover crops weed management system.
Planting Costs
The Zimmermans started planting-in green on a few trial acres three years ago.
“It wasn’t a failure. It was a learning experience and we did take a little bit of a yield hit. Last year over three-quarters of our ground was planted green. We did chemically terminate with the old program the rest of it,” he noted.
An example of how planting into green cover crops worked for him, Zimmerman applied a burndown on 40 acres followed by a post application of Durango at a cost of $55 per acre. Those soybeans average 60 bushels per acre.
On the adjacent 80 acre field, the cover crops were terminated with Zimmerman’s crimper, and Durango and Outlook were applied post at a cost of $30 to $33 per acre. Those soybeans averaged 58 bushels per acre.
“Yes, we lost 2 bushels, but we gained on chemical savings of roughly $20 some per acre and soybeans are not at $10 a bushel right now. So, we put money in our pocket,” he said.
“One of the big things on utilizing cover crops that people get wound-up on is what are your yields doing. We feel even if we take a slight yield hit it more than pays for itself between the fertility and the weed management.
“The biggest thing is our average yields are at or above county average. Our corn yields have continued to climb every year. Our soybean yields have continued to climb every year. So, if we’re saving money and also yielding better, it’s a win-win all the way around.”
Cover Profit
Putting all of the estimates together, using no-till and cover crops over conventional tillage and no cover crops saves $54.53 per acre. The cost of planting cover crops with a blend of five or six species is $22.70 per acre, resulting in net savings of $31.83 per acre.
“The $31.83 per acre in savings equates 9.8 bushels ($3.25 per bushel for corn) and 3.78 bushels of soybeans at $8.60 per bushel. So, if you’re approximately 10 bushels to the acre of corn yield under the average, you’re breaking even. We’re not seeing that. We’re usually 2 to 3 better every year it seems like,” Zimmerman noted.
“With soybean acres at $8.60 per bushel we can take a 4-bushel to the acre hit. Again, we’re not seeing that. We’re staying right at our average or slightly increasing every year.”