You have likely seen countless reasons for considering cover crops. I would like to add my own "Top 10" list based on what I’ve observed working with growers over the past several years.
Here are 10 benefits of cover crops that should grab your attention.
1. Reduce leaf disease pressure. The exact mechanism is not known. However, cover crop residue appears to prevent pathogens in previous crop residue from reaching growing corn. Cover crop residue provides an additional layer of unfavorable host tissue.
2. Minimize soil erosion. Soil erosion is a big problem on many farms. We’re losing millions of tons of topsoil every year to erosion. Cover crops can not only help reduce erosion, but also help improve the organic matter content of the soil and boost yields.
3. Prevent nitrogen, phosphate, potash and other nutrients from leaching. Cover crops tend to keep nutrients in the upper layers of the soil where they can be easily available to the following crop. It’s even more important to have cover crops growing in the fall after a drought to capture unused nitrogen.
4. Improve root mass and carbon-nitrogen ratio. Root mass becomes so important in droughty conditions. More root mass is crucial in capturing water.
5. Reduce weed pressure. We know even early weeds can hurt crops. A reduction in weed pressure will improve crop yields. Many growers report that cover crops help minimize marestail in soybeans, and some report the cover helps reduce weed pressure in general.
6. Help break down hardpan and compacted layers. Forage radishes that grow roots almost 1 inch thick and more than a foot long can penetrate compacted soil layers. Other cover crops can help loosen the soil as well.
7. Raise earthworm populations. Some estimates indicate that populations of these useful worms may increase by 15 to 32 times following cover crop use. Numbers for other worm species also go up.
8. Increase organic matter content. Cover crops also improve cation exchange capacity of the soil over time. High organic matter helps improve water retention and increase yields.
9. Reduce fertilizer needs. This should be tracked through soil testing. The benefit may show up over time.
10. Boost soil health. Soil health is a primary reason for considering cover crops. Over time it also means improved tilth and fewer soil insects that can harm the following crops.
All these factors help improve crop yields over time by improving soil health.
You don’t need to spend a lot of money on seed for cover crops. For example, Marshall Alford in Dearborn County buys regular wheat from neighbors in his area. He asks his fertilizer plant personnel to blend it with about 60 pounds of potash per 80 pounds of wheat and spread it after crops are harvested.
He also applies some nitrogen later to help the wheat grow. Note that not everyone recommends wheat as a cover crop. Some also prefer other seeding methods. The point is that sowing a cover crop doesn’t have to entail a huge investment per acre.
Should we use cover crops? For me, it’s a no-brainer!
Nanda is president of Agronomic Crops Consultants LLC, Indianapolis. Email him at [email protected], or call him at 317-910-9876.