“Why has there been such an increase in cover crops in recent years?” asked Mike Plumer at the Oregon Seed League meeting yesterday.
- First, it’s about capturing the nutrients in the field, keeping nutrients from running off during winter and spring months. In a normal year, there can be 90 lb/ac of nitrate available for annual ryegrass or another cover crop to take up. In 2012, because of the drought, there was probably well over 100 lb/ac in many places. With the cost of nitrogen going to $1500 – $2000/ton, it’s easy math to see why cover crops make sense.
- “Cover crops can double your yields,” Plumer said. Though rare, in a terrible weather year like 2012, there were lots of instances where farmers more than doubled their yields with annual ryegrass and other cover crops. The secret is rooting depth. Without cover crops, corn roots starve out quickly as they hit compacted layers. With annual ryegrass roots penetrating to beyond 6 feet, they allow channels for corn roots to follow.
Plumer’s caution to the group was in terms of cover crop seed quality. “There are about 7 varieties of annual ryegrass that are hardy enough to weather a Midwest winter,” he said. Because of the popularity of annual ryegrass, however, seed provided to unwary Midwest farmers may not be among those seven varieties. Plumer said it would be a tragedy to flood the Midwest with seed that won’t grow well. His advice to buyer’s; beware…and ask lots of questions about the source and variety of seed. His advice to seed growers: make sure you’re sending us varieties that will withstand Midwest winter conditions.