Cover crops have plenty of agronomic and water quality perks. So, why don’t more people plant them?
Well, they aren’t all puppies and rainbows. For cover crops to work, they must be killed close to planting the cash crop.
“Otherwise, that cover crop's going to keep on growing and compete with your cash crop,” said Liz Stahl, University of Minnesota Extension crops educator.
A 2019 U of M trial showed corn yield dipped 16 bushels per acre when termination was delayed from May 2-21 for a May 12 corn planting. Termination also takes extra labor and time, and adverse spring weather can compound a tight time window.
Then there’s the expense. James Hepp, a Rockwell City, Iowa, farmer and member of the farmer-conservation trio “The Lobe Rangers,” terms his program as a “Cadillac” plan. Costs tally between $30 and $35 per acre to drill cover crop seed.
However, he points out that such systems should be judged on a long-term basis. They differ from strategies such as fungicides for disease control, where farmers apply them for a one-shot return on investment.
“You need to do a bundled approach, with multiple things like cover crops, in-season nitrogen and reduction of tillage to expect the results predicted in the Iowa Nutrient Reduction Strategy,” Hepp said.
Cost-sharing helps
There’s also the question of who pays — renter or landlord?
Hepp covers all cover crop costs, which he said results in payback over the long term. However, it’s important to have a long-term agreement on rented land to glean these perks, he said.
Cover crop cost-sharing can help. Doug Adams, who farms near Humboldt, Iowa, said a $25-per-acre cover crop payment over 500 acres is available in the cover crop initiative in 22 counties in the Greater Des Moines Watershed Program.
These can be stacked with those of the Water Quality Initiative program. First-time users can glean $30 per acre over 160 acres, while previous users can glean $20 per acre.
“Between those two programs, you can cost-share 660 acres,” Adams said.
Teaming up
Lee Tesdell garners $40 per acre in cover crop cost-sharing through a Practical Farmers of Iowa program and the WQI program. The Slater, Iowa, fifth-generation farmer and landowner also has installed several edge-of-field practices via cost-sharing, including three terraces, Conservation Reserve Program buffer strips, a waterway, a wood chip bioreactor, four saturated buffers and three prairie strips.
Since bioreactors and saturated buffers are a high priority for the USDA-Natural Resources Conservation Service, they entail 90% cost-sharing, said Jason Johnson, NRCS state public affairs specialist.
It’s difficult to measure how much nitrate is being saved by cover crops, although Tesdell said other ecosystem benefits are clear. However, the wood-chip bioreactor on the edge of a field has filtered 58% to 77% of nitrates that flow through that particular drainage tile.
Some upkeep is required, as he replaced the bioreactor’s wood chips in December 2024 after 11 years.
“We can’t get them all, as there is a bypass when heavy rains occur,” Tesdell said of nitrates. “They are not a panacea. But they are an important tool, and we can assure the taxpayer their money is well spent.”
Other hurdles
Finding landowners willing to share in the cost of such practices, or even permit them on their land, can sometimes be difficult, Tesdell said.
“I talked to one farmer who is very environmentally conscious,” Hepp noted. “She no-tills, she cover crops, but she can’t talk some of her landowners into doing it on their land.”
It also can be unnerving to start a new practice. Stahl advised initially pushing the easy button with cover crops. For example, a cover crop that winterkills — such as oats — nixes the need for termination the following spring.
Planting a cover crop before soybeans also doesn’t incur the yield loss risk as it does with corn, Stahl added.
Cover crops work best with no-till, Adams said. But they still can grow in areas where tillage is frequently done, such as in north-central Iowa. Farmers there have flown on three-way mixes of turnips, radishes and rapeseed with a drone.
“It doesn’t cost a lot, and cost-share can cover that,” Adams said. “And it winterkills, so you don’t have to worry about termination in the spring.”