Barley cover crop, a cool-season annual, seeds adds lots of organic matter, provides erosion control, weed competition and are suitable for grazing or for grain production. Studies have shown barley can discourage weed germination by producing allelopathic chemicals and are therefore good for weed competition. Choose between bearded or beardless for planting in your pasture for grazing (before seed heads develop) or grow your own for grain to eat or make beer. Hardy to zone 8, plant in the fall or early spring. Barley can be used to absorb excess nitrogen in the soil and release it when the plant decomposes.