One of the revisions in new rules for Indiana 4-H and FFA soils judging allows students to cite more reasons why a farmer would want to plant cover crops on a particular field. Is it sloping and you simply need a cover crop for erosion control?
Or do you need a cover crop to scavenge and hold on to unused nitrogen on a level soil? Maybe you need a cover crop to scavenge nitrogen because the subsoil is sandy or the field is underlain with coarse sand and gravel. These are just a few of the places where cover crops might provide benefits.
Soils specialists who prepare information for Salute Soil Health are part of the Indiana Conservation Partnership. Those from the Natural Resources Conservation Service providing insights include Don Donovan and Clint Harrison, district conservationists; Susannah Hinds, grazing lands specialist; Kris Vance, public affairs specialist; Tony Bailey, state conservation agronomist; and Shannon Zezula, state resource conservationist.
Why plant cover crops? It seems like a simple question. Hinds usually gets a laundry-list answer if she asks farmers. But the details really do make a difference when picking the species of cover crops to plant, she says.
“Do you want to break up a compaction layer?” Hinds asks. “Then select a species with deep roots or large amounts of root biomass. Picture the deep tubers of radishes or the mass of roots of cereal rye.
“If you want to increase soil organic matter, select cereal rye or annual ryegrass that will produce high volumes of organic material above- and belowground. They survive winter and grow quickly in the spring.”
Cover crops need to be planted early and terminated as late as practical to maximize growth, Hinds says. Legumes such as crimson clover will add nitrogen. Brassicas such as turnips, radishes and rapeseed, as well as many grasses, store excess nitrogen.
“Knowing how you want to improve your soil will help you determine what you plant,” she says. “Have a solid management plan that includes termination and contingency options when making your species selections.”
Do you wait until after harvesting corn to plant cover crops? In most parts of the state, your options are greatly reduced, Donovan says. While wheat is an option, most farmers after corn harvest use either cereal rye or triticale — a cross between rye and wheat. Donovan says both of these cover crops can be planted throughout the state up until late October with excellent results. Others have noted cereal rye can be planted in November and still do well most years. Cereal rye and triticale do most of their growing after spring warmup.
There are several seeding options for these cover crops, including using a precision planter or drill, mixing with fertilizer and spreading, or using an air seeder on a vertical-tillage implement.
A cover crop will provide you with excellent soil health benefits as you plan your next crop, Donovan insists.