It may have begun in Canada, the practice of planting annual ryegrass as a cover crop into knee-high corn. Based on the pioneering work of cover crop innovators like Daniel Briere, an agronomist with Plant Production Quebec, hundreds of northern Corn Belt U. S. farmers are now doing likewise – planting annual ryegrass as a cover crop in the spring.
One of the biggest impediments to cover crop adoption has been planting them in in the fall after harvesting the main cash crop. Especially in the northern Midwest, where harvests can come off the field just before cold weather sets in, planting a fall cover crop has been difficult. Planting in the spring is therefore a great option.
Here’s a video of the equipment that’s being used to broadcast annual ryegrass when your corn is at five or six leaves. After it germinates and gets established, the annual ryegrass goes dormant for most of the summer because it is shaded by the corn. Then, in the fall, it takes off again, after harvest, and stays alive throughout the winter, provided there’s enough snow cover. Then, in the spring, the idea is to kill the annual ryegrass in the weeks before planting the next corn crop.
Although the idea of planting a second crop into the cash crop seems counter intuitive, it looks like the synergy of annual ryegrass and corn builds soil and adds bushels of extra corn at the end of the season.
Another benefit of interseeding is that, during corn harvest, the combine is rolling over the ryegrass, which further protects the soil from compaction and giving the combine added traction.