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Planting Cover Crops on Prevent Plant Acres? Read This First.

Have a plan in mind before buying any seed, specialists advise.

If planting corn or soybeans this spring isn’t in the cards and you’ve opted to take the prevent-plant provision of crop insurance, there are a host of reasons why planting cover crops in lieu of keeping land idle is a good decision. 

Bert Strayer, cover crop lead for LaCrosse Seed’s west territory, says it is important for growers to think about the goals they have in mind for what a cover crop can accomplish. Whether weed control, erosion control, taking care of moisture, or use as forage, figure out the priorities. “Then we can backfill the time line and determine the timing of planting, what makes sense for the grower, and what species provide a benefit,” Strayer says. 

The benefits of a cover crop during the prevent-plant period are numerous and are listed below. Yet, growers need to answer these questions first, he adds:

  1. When is the earliest – and the latest – you can plant a cover crop?
  2. What will you rotate into next year? The next cash crop may determine whether the cover crop you select winterkills or can overwinter.
  3. Are you planting a cover crop for cover or do you want the potential of forage?
  4. How will you seed the cover crop you select? Will you broadcast the seed or can you drill it?
  5. What herbicide or fertilizer program did you use prior to claiming prevent plant? If you applied herbicide, make sure the covers are compatible. If you applied fertilizer, try to choose a cover crop that can cycle that nitrogen so it is not lost.
  6. Be flexible. With the increase in demand for cover crop seed this spring, supply of popular species is limited. 

Avoid Fallow Syndrome

For starters, consider fallow syndrome. That’s when corn planted following cropland that has been idled for a season gets off to a slow start and shows symptoms of phosphorous deficiency. That’s because fields that lay idle have dramatically reduced populations of vesicular arbuscular mycorrhizae, or VAM, which has a symbiotic relationship with corn and small grains, according to a 2016 report from the University of Missouri. 

“The mycorrhizae develop around the corn roots and assist the root in taking up nutrients, primarily P and Zn. The mycorrhizae benefit by accessing the sugars from the root system of the host plant. As plants grow out of the phosphorus deficient symptoms, they have remained pale and stunted in the most impacted fields,” writes Greg Luce, Mizzou plant scientist. 

In short, having some kind of crop growing on the prevented-plant acres can counteract fallow syndrome. Caution: Not all cover crops can thwart fallow syndrome, Luce adds. Brassicas – like turnips and radish – don’t host VAM. If used as a cover crop during this prevented-plant period, they need to be mixed with host cover crops; typically grasses like cereal rye, wheat, or oats.

Manage Water

All that extra moisture that’s wrought havoc on your cropland this spring will eventually evaporate. Cover crops, however, can hasten the process by consuming excess moisture. 

Think roots, not iron. “If you think you’ll remove water by tillage, it won’t work,” says Lee Briese, agronomist at Centrol, Inc., Twin Valley, Minnesota. 

“Digging” out soil water via tillage can lead to more problems, like compaction or creating a hardpan. However, planting a blend of cover crops will prompt root growth of varying depths and canopy, helping to prevent compaction and hardpan. 

Make sure to wait to plant cover crops until field conditions are suitable, Briese warns. Planting into muddy conditions is asking for trouble.

“Telling farmers to do nothing is the worst thing you can tell them,” he admits. But waiting for good planting conditions – as difficult as that may be to do – is worth the headache.

Keep Weeds at Bay 

One important attribute of cover crops is the ability to suppress weeds. Tillage is a short-term suppression tool, but cover crops offer seed-long suppression, Briese says. 

“Tillage won’t give long-lasting residual,” he explains. “Tillage will kill a lot of weeds, but within four days, they will come back.” Cover crops suppress weeds by canopying the ground and providing competition for seedlings, thereby, providing long-lasting weed control and serving as another mode of action. 

The trick is, fit cover crops to the weeds you need to control and use the cover crops as one of the layers of protection. Start with a clean field and plant cover crop species that outcompete the weed species you target.

“I recommend growers determine what weeds they have in their fields. Weeds are the first priority; fit cover crops to those weeds,” Briese says. 

For instance, let’s say you use Callisto herbicide to beat broadleaves. A cover crop of oats in combination with Callisto can help provide season-long control of weeds like waterhemp and Palmer amaranth. Because it’s a grass species, the fallow syndrome shouldn’t apply next year. That’s just one example, but your Extension agent, a cover crop seed dealer, or resources from the Midwest Cover Crop Council can help you determine which combination of cover crops, herbicides, and target weed species fits your operation. 

TALK TO YOUR INSURANCE AGENT!

This cannot be emphasized enough.

Before any decision is made about whether to plant or what to plant, “we recommend growers are in very close contact with their insurance provider,” emphasizes LaCrosse Seed’s Strayer. “We don’t want to make assumptions that everything we might suggest is in compliance. First and foremost, you have to be in compliance.” 

For instance, growers who seek to plant a cover crop species, or multiple species, on prevent-plant acres – with the goal to produce forage – cannot harvest that crop before November 1. Same for any grain crop that might produce grain. Once growers accept the indemnity for prevent plant, a cover crop cannot be harvested for financial gain from those acres. 

Again, Strayer says to make sure and stay in close contact with your crop insurance agent. 

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