Warm-Season: Seeding Year Management
Because warm-season grass seedlings compete poorly with weeds, sites with severe perennial weed problems such as quackgrass or broadleaf weeds should be avoided until weeds are controlled.
Although warm-season grasses are good producers on low-fertility soils, maintaining adequate phosphorus and potassium levels increases stand vigor and production when levels of these nutrients are low in the soil. Determine lime and fertility needs by conducting a soil test. Lime is not necessary if soil pH is above 6.0. In the absence of a soil test, apply 0-60-60 per acre. Nitrogen is not recommended for use at establishment because it leads to increased competition from weeds. However, on sites with low fertility, good weed control, and a good stand of grass, apply 25 to 30 pounds of nitrogen per acre.
Both species of warm-season grasses should be seeded alone either on a conventional, tilled seedbed or no-tilled into grain stubble (see “No-Till Forage Seeding,” later in this section) between mid-April and late May. Early seeding helps break seed dormancy and improves establishment. The seedbed should be free of weeds, fine-textured, and firm. Plowing, disking, harrowing, and rolling or cultipacking generally are required. Band seed with a drill with press wheels at a depth of ¼ inch. If seeded broadcast or drilled without press wheels, a rolling or cultipacking after seeding is necessary to ensure a good firm seedbed.
If plowing and disking is done early, weeds can be allowed to germinate and then eliminated with a contact herbicide or a light harrowing or disking before seeding.
Switchgrass seed is hard and slick and can be handled without special drills. Big bluestem seed is chaffy and does not flow well unless it has been debearded, a process that removes the chaff and hair from this seed; therefore, debearded big bluestem seed should be used. Recommended seeding rates are given in Table 1.8-5.
Normally, the seeding year stand should not be harvested unless there is unusually good growth and the stand is vigorous. If a harvest is made, cut when plants reach 18 to 24 inches in height (late boot stage). Leave a 4- to 6-inch stubble. Allow enough time for at least 12 inches of fall regrowth before frost. Plants can be harvested after frost without being damaged.