It soon will be time to make management decisions for 2021. This is also a great time to see how your fields held up through spring and summer rains. Perhaps harvest will be the first time you cross your fields, especially cornfields, since early in the crop year.
What can you learn during harvest? Did the combine bounce over gullies or sedimentation bars? In extreme cases, did you have to maneuver around severely eroded areas? If your fields were eroding this summer, what will winter leave behind? What are options for next year to address these issues?
Erosion control is just one benefit of crop residue. Spread harvested residues evenly across the full width of the combine header. The residue acts as a blanket and helps lessen the impact of raindrops on the surface, increases infiltration, and reduces concentrated-flow runoff that causes gullies. Spreading residue evenly also will help soil conditions be more uniform in the spring.
Erosion control is also a benefit of using cover crops. They protect the soil by providing ground cover and roots to keep soil in place. Cover crops used in a long-term no-till system will improve aggregation of soil particles, thereby improving infiltration. Soil organic matter levels will improve, building a more resilient soil that won’t be as susceptible to erosion.
How cover crops help
A cover crop mix for erosion control should contain a grass such as oats, cereal rye, barley or annual ryegrass. If you’re concerned about spring erosion, cereal rye or annual ryegrass is best if you’re comfortable with termination before planting.
Brassicas and legumes should be included to provide other benefits. Brassicas help with leftover nutrient uptake and battling soil compaction. Legumes provide nitrogen production for the following crop. If left to flower, they provide food for beneficial insects.
If you’re not ready to plant an entire field to a cover crop, smoothing eroded areas and planting wheat or rye makes a tremendous difference in erosion control. Make note of areas of concern, and seed prior to winter.
Erosion will be minimized, keeping nutrient-rich soil in place. This will also prevent disking in the spring to prepare for planting. Disking loosens the soil and increases risk for further erosion.
Where erosion is a severe concern, some farmers experienced with cover crops are trying intercropping — planting a cover crop during sidedressing with corn between the V3 and V7 growth stages. Planting between these growing stages has minimal effect on yield and still allows for postemergence herbicide applications before the cover crop germinates. There’s even potential to provide nitrogen to the corn crop if legumes such as medium red clover or crimson clover are planted.
Increasing residue cover by reducing tillage is a good starting point for resolving soil erosion issues. Crimping cover crop residue at planting further armors the soil surface. But neither crop residue nor cover crop residue are actively living plants and therefore are subject to running off during heavy rain events. Learn more about intercropping.
If erosion in your fields is an issue during harvest this fall, consider using cover crops next year. Start with the fields that seem to erode the most.
Harrison, Donovan and Musser are district conservationists with the Natural Resources Conservation Service. They write on behalf of the Indiana Conservation Partnership.