Cover crops were once thought of as something very old farmers with a few acres flew on in the fall on rolling fields, just trying to save some soil. That goes as far back as the 1950s. Then in the 1980s, there was interest in using cover crops that would provide nitrogen for the next year's crop. Programs such as 'grow your own nitrogen' became buzz words. Hairy vetch was tested even in university trials at the University of Kentucky.
All the pieces weren't there yet, it seems. Hairy vetch was hard to kill, and if allowed to grow with corn, could choke out the corn. The decaying cover crops didn't always release nitrogen to the growing corn crop at the right time. And planting equipment available at the time didn't always do a perfect job getting good stands in dead cover.
The drive to establish cover crops is back, and this time it's stronger than ever. Farmers in Ohio, Indiana and Iowa all say it's a way to build up the soil. Besides protecting the soil in the winter, it's also say to capture nitrogen left over from the crop before it seeps away in tile lines during the winter and following spring. And it can help build healthier soil through deep rooting of some of the newer cover crops being tried, which include annual ryegrass and oilseed radishes.
There's still one obstacle today that some farmers say they've conquered, but others haven't. That's when and how to bring the cover crop down in the spring. Planting equipment can plant through dead residue, but getting the residue dead, especially if the cover crop is annual ryegrass, can still be a challenge, says Bill Johnson, Purdue University weed control specialist.That's probably another area where more answers will be needed if cover crops are finally going to earn their place to stay on a majority of farms. There is no question that on some large farms, even no-till farms, cover corps are already integrated and part of the secret to better soil conditions and higher yields. Getting those farmers to give up cover crops would be a big battle.