Mike Trammel, Oklahoma State University Cooperative Extension Service SE District Agronomy Specialist. – Overseeding cool-season annual forage crops such as annual ryegrass and small grains (cereal rye, wheat, oats, and triticale) is a widely used establishment practice in the South for grazing or hay production. These crops can produce high-quality forage in late fall, winter, and spring, depending on establishment method and fertilization. They can be established using tillage or by overseeding existing pastures. The biggest challenge for managing these cool-season annual forage crops when overseeding is to manage the growth of the warm-season grass component (i.e., bermudagrass or bahiagrass) so that it does not impede the annual ryegrass or small grain germination and establishment. The following tips can be used as guidelines to ensure a successful stand when overseeding perennial warm-season pastures:
- Take a representative soil sample, and make sure the perennial warm-season pasture is grazed or clipped short (about 3 inches).
- Annual ryegrass can be drilled or broadcasted. Plant annual ryegrass seed at 20 pounds per acre if drilling or 30 pounds per acre if broadcasting the seed. For overseeding with small grains, prepare the seed bed by lightly disking to increase seed-soil contact. After seeding, use a chain harrow or roller to make sure that all seed reaches the ground and is not stuck in the warm-season stubble. Another preferred option—is to use a no-till drill, which also requires that the pasture be clipped less to about 3 inches. In some cases, chemical sod suppression can be applied such as a light dose of glyphosate (5–8 ounces of a 41 percent product per acre). Cool-season annual planting can occur 5–7 days after a glyphosate application. When using a no-till drill, make sure it is calibrated correctly to place the seed at the recommended depth. Small grains can be planted at seeding rates of 90–120 pounds per acre. Seeding rates need to be adjusted depending on whether cool-season annual forage crops are being established as a monoculture or mix.
- Apply phosphorus and potassium based on soil test recommendations. It is recommended to apply 50 pounds of nitrogen per acre at planting and another 50 pounds of nitrogen per acre in late winter before spring growth begins.
- Once the cool-season annual forage crop is established, it is best to keep animals off the pasture until the plants reach a grazing height of 8–10 inches. Graze down to about 3 inches of stubble height and remove or rotate the animals from the pasture to allow recovery.
- Keep in mind that it is important to graze down cool-season annual forage crops in late spring to avoid suppression of summer perennial warm-season pastures. It is best to increase your stocking rate in the spring, when annual ryegrass is at peak production. Annual ryegrass will use the available moisture and then shade the warm season grass crop as it is trying to break dormancy. The result is a severely weakened stand of warm season grass with a low yield potential.
