It’s still too early to see corn or soybeans poking through the rich Iowa soil, but I’ve certainly noticed more green as I’ve traveled around our state recently. That’s because cover crops are coming out of their winter dormancy and are starting to do their work reducing erosion, building soil health and improving water quality.

Iowa State University research shows that rye cover crops, the most popular cover crop in the state, reduce nitrogen and phosphorus losses from farm fields by nearly...