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15 cover crop questions and answers
How do I start?
Slowly. “Do a little patch at a time,” says Jack Maloney, a Brownsburg, Indiana, farmer. Maloney initially with 40, then 80 and 160 to the point where 1,100 of the 2,700 acres he farms are now covered with cover crops.
When should I start planning?
If you’re planning to seed cover crops in the fall, March is a good time to start planning. “We’ll hear things like ‘I went to the co-op and they didn’t have any seed,'” says says Nick Bowers, a farmer and co-owner of KB Seed Solutions, Harrisburg, Oregon. “Well, the reason is that you waited to order seed just two days before planting time. You have to start thinking about it long before that.”
Where should I plant them?
Start with your worst field. “If you have a field that’s competed and has low organic matter, try it there,” says Wayne Kizer, co-owner of KB Seed Solutions. “That way, if you stub your toe, it’s not on your best field.”
What kind should I plant?
Kizer recommends asking yourself what you are trying to accomplish. Stop erosion? Break up compaction? Sequester unused nutrients? “That can help you determine your goals and where you will start,” says Kizer.
Is there an easy cover crop for rookies?
Try radishes. They’re easy to establish and often die before planting your main crop next spring. Thus, there is little cover crop competition during next spring’s planting. “I call radishes a gateway drug to cover crops,” jests Kizer. “They grow, then die in winter. You will forget you have a cover crop.”
Are there any drawbacks to easy?
Yes. “One drawback to radishes is we have had them grow sideways in hardpan soils,” says David Songer, who farms with his father Steve near Veedersburg, Indiana. This fails to shatter hardpan. “Radishes have just one taproot,” he says. “Annual ryegrass has a bunch of fine hair roots that give many ways to penetrate the hardpan.”
So why not plant annual ryegrass?
From a weed scientist perspective, it’s too hard to kill.“I don’t think it is a good idea for a cover crop,” says Kevin Bradley, University of Missouri Extension weeds specialist. Besides surfacing in subsequent years, it’s resisted multiple herbicide modes of action in Australia. Bradley fears resistance could surface in the United States.
When should I plant cover crops?
Late summer to early fall works well. In the case of annual ryegrass, mid-October is the latest planting date. Any plantings after this time may not reach the desired 8- to 10-inch height over winter for optimum nutrient scavenging and erosion protection.
Should I fly or drill them?
You may fly cover crops into standing primary crops. “Flying them on in standing corn can work great if you get rain afterward (to incorporate it into the soil,” says Maloney. Drilling cover crop seed is more foolproof, though. Flying cover crops on is a problem in soybeans, as its dense crop canopy can cause seed to ricochet and not penetrate the soil.
How much does all this cost?
Budget around $35 per acre for seed and an aerial application, says Bowers. Drilling can cost less, but much depends on equipment ownership and finding time to do it during harvest. Cost sharing that covers much of this cost is available under the Environmental Quality Incentives Program (EQIP).
Won’t cover crops backfire during drought?
Joe Bachman, who farms near Roanoke, Illinois, notes cover crops can ding primary crops during drought. However, the stress isn’t that much different than primary crops grown without cover crops. “They also can provide a mat, though, that helps retain soil moisture,” he notes.
Can I mix different types of cover crops?
Yes. Just as a football team uses many kinds of player talents, cover crop mixes bring lots of different perks to the table. For example, a balanced diet of different kinds of cover crops boosts earthworm populations. “You have to feed them a balanced diet, not wheat straw all the time,” says Dwayne Beck, manager of the Dakota Lakes Research Farm near Pierre, South Dakota.
How can I plant through cover crops?
It’s easier than you think. Maloney fits his planter with Martin Residue Managers up-front and Dawn closing wheels on back. The residue managers clear cover crop residue, while the closing wheels provide the right amount of soil covering the seed.
When should I kill the cover crop?
Spray when the cover crop is actively growing. “You don’t want to spray when it is less than 50 degrees during the day and 40 degrees at night,” says Bowers. If only partially killed, annual ryegrass can become the equivalent of a noxious weed. Optimum time prior to planting varies.
Why should I care about water hardness?
That will impact the efficacy of the kill with your herbicide mix. “The pH of the water carrier has to be below 5 for glyphosate,” says Bowers. “Hard water tends to tie up calcium and iron.” This can impact glyphosate’s efficacy on the annual ryegass.
What other practices accompany cover crops?
No-tillers are apt to have more success with cover crops, since they are more prone to brace technology, says Kizer. "I don’t think a conventional farmer would get as much benefit from a cover crop because of the tillage they are using," he says.
There’s a lot to discover about cover crops. Here are some key questions to ask before jumping in.