I caught up with Jeff Rasawehr of Center Seeds the other day to learn about why he likes to add “nurse crops” when he’s seeding in a new pasture or hay field. A nurse crop for forage plantings is an annual that gives forage plants an extra boost as they’re getting started. The nurse crop holds soil in place, cuts down on weed pressure, and provides a little shade for the young forage seedlings that might be harmed by excessive sunlight.  Nurse crops can also power up yields on the first harvest, providing extra feed when the forage crops haven’t gotten going full force yet.
Jeff likes starting a new stand of forage with oats as a nurse crop because of their ability to stimulate mycorrhizae in the soil. Oats provide some additional benefits too. Oat roots boost the interaction of different beneficial fungi  when they grow, stimulating the rhizosphere. The rhizosphere is that soil area right near the roots, and when it’s enhanced, it increases nutrition to your young forage plants, getting them off to a successful start. Oats are also a good choice because they don’t outcompete your intended forage stand. Plant them as a nurse crop, and they will grow, but they disappear when your stand starts coming in strong.
The only other nurse crop Jeff really recommends is barley. In the fall, he suggests planting a winter barley, also sometimes called “fall barley.” In the spring, he likes spring barley. Barley helps increase the availability of phosphorus and potassium (P and K) that might otherwise be locked in the soil, unavailable to plants. It’s the Barley’s fibrous roots that support microrrhyzal activity, so plants can access these nutrients.
How much nurse crop seed do you need in your mix? That depends on the time you’re planting and what you plant to do with your pasture. For his area If you’re seeding early, say around mid-March, Jeff suggests including 20-25 lbs /acre of your nurse crop. For later seedings, around April 15-20, then Jeff suggests 15 lbs. Later in May, he’d suggest going back up to 20-25 lbs. The way he explains it is that if you perceive tough conditions, you should seed in more nurse crop.
You can add your nurse crop with your forage, or broadcast them in afterwards. If you are drilling the nurse crop in with your forage crop, calibrate the drill for the forage, not the oats. If you are broadcasting them, as with forage crops, seed-to-soil contact is key.
To make sure your nurse crop doesn’t compete with your forage, avoid nitrogen application. You don’t want the nurse crop to compete with your forage though, so avoid nitrogen application, as it will help that nurse crop compete. If your forage crop is going gang busters and threatening to overshadow your forage, you also mow off the nurse crop while it’s in the vegetative stage.
As always, before you plant, take a soil sample and get it tested. Check for soil pH and soil nutrients so you are not throwing away good money on a planting that isn’t going to be able to live up to its potential.
