Late spring and cover crops can still work04/24/2018 | Soil Health, Water Quality
By Carol Brown, ISA environmental communications specialist
Winter is finally loosening its grip on Iowa.
Across the state, farmers are getting anxious to get into the fields for planting. If they have cover crops, they could be even more anxious. But corn and soybeans are resilient and there are ways to adapt for planting in fields with cover crops during this cool, wet spring.
Nathan Paul and Theo Gunther, research team members with the Iowa Soybean Association (ISA), agree there is still time to manage both cash and cover crops to get this year’s growing season going.
“There is no need to over-react,” says Paul. “There are cover crop management tips to use that will help.
The cover crop termination window for corn will be short this spring. Typically, 10 days is the ideal time frame when terminating something growing like a cover crop. But there won’t be that much lead time this spring. Farmers can still plant into cover crops with a low risk of yield loss, but cover crop burndown should be done immediately or as soon as possible.”
With this spring’s cold temperatures and snowfall, cover crops have not grown significantly, yet. The risk of the cover crop getting out of hand prior to its termination and planting may be a non-issue, compared to a warm spring. Gunther said that if there is not much cover crop growth, the less time will be needed to terminate it. The cover crop becomes less of a management factor.
Planting process points
“Planter settings will be key, as usual, but will be different with shorter cover crops,” says Paul. “The planter needs to be set properly, but planting into live, or recently terminated, cover crops will require special attention to downforce pressure and seed depth settings.”
Whether the field has cover crops or not, soil temperature is a highly important component of the planting equation.
“Calendar dates and soil conditions are two different things,” said Gunther. “Planting into a cold seedbed can be a bigger issue especially in no-till and cover crop situations. This is more important than waiting for a good day to terminate cover crops. Soil temperature will drive how quickly germination and emergence will occur.”
Cover crops still working
“Shorter cover crop biomass doesn’t mean the crop didn’t perform well,” said Gunther. “They are still doing the job of protecting the soil from erosion and building soil organic matter at the root level. Especially if the cover crop was well-established last fall. If there was good root growth, the cover crop could take off quicker this spring, so watch them closely.”
Applying some nitrogen near the row pre-plant or with the planter is consistently a good practice with cover crops, but particularly if the cover crop was recently killed, Paul said, as the cover crop won’t be releasing nitrogen for a while.
Paul and Gunther’s advice to Iowa farmers for the near future is to be patient. The forecast for the next few weeks is looking up.
Contact Carol Brown at: firstname.lastname@example.org
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