Dave Nanda first saw how forage radishes could break up compacted layers some five years ago. The practice was slow to catch on, but now more farmers are using not only radishes but also many other crops, either in combination or alone, in attempt to improve soil health.
Loosening up the soil is one benefit. Now, the most important advantage is capturing nutrients that were left behind by a crop that couldn't use all the nutrition that was applied.
"It's more important now than ever before to use cover crops this fall," says Nanda, now an independent crops consultant and director of genetics and technology for Seed Consultants, Inc. "There is a lot of nitrogen out there that corn plants never got to and didn't use. It will be gone by next spring if farmers don't do something to keep it around."
One option is to plant cover crops that will take the nitrogen into the roots and tie it up in plant material. They will also take up other nutrients, including phosphorus and potassium, but those aren't as easily lost from the soil. For the most part, those will still be there next spring for the 2013 crop. However, if nitrogen is left to its own devices, sitting in the soil, it will leach out over winter. It won't be available to the crop next year, but it will wind up in tile discharge and streams and rivers. Environmental groups will be watching and monitoring. Expect them to be long on pointing the finger at farmers and short on accepting or passing along the explanation as to why levels could be higher after this crop than during most years.
The window to plant some cover crops is much narrower than others. Right now there is an opportunity to plant several crops. Cereal rye, gaining in popularity, can be seeded through the bigger part of October in most of Indiana. The earlier it's planted the more nitrogen it can capture before cold weather shuts down fall growth, but if you can't get other covers seeded on time, it's an option worth considering.