With ample moisture falling in the past few weeks, South Texas producers have more options for establishing winter pastures. Cool season annual forages may be expensive to grow and maintain but might be cheaper than providing supplements from hay, grain or range cubes or pellets. Proper establishment and species and variety selection are critical.
Legumes like burr medics and clovers are good for the soil and provide good nutrition for livestock; however, dry matter production will be late in the cool season, mostly in early spring. Cool-season legumes are an attractive option to decrease production cost of nitrogen fertilization because legumes have the ability to fix atmospheric nitrogen. Annual clovers can contribute about 75 to 100 pounds of nitrogen per acre for subsequent grass crop. They are, however, only able to fix nitrogen from the air if host-specific strains of Rhizobia bacteria are present in nodules on their roots.
In South Texas, the general recommendation is to overseed cool-season annual forages from 6 to 8 weeks before the average first killing frost. Correct timing for establishing cool-season annual forage cannot be overemphasized. If planted too early, warm temperatures and the competitive nature of the warm-season perennial grass sod can result in stand failure.
Planting cool-season forages with a drill is usually better than broadcasting as more of the seed is placed at the proper depth. When broadcast, the seeding rates should be increased 25 percent to 30 percent to compensate for fewer seed becoming established plants.