Nitrogen fertilizer prices have reached over $750/ton for urea (over 85 cents/pound of nitrogen), with expectations that it could reach over $1,000/ton. This is a good time to consider using legumes in your pastures to replace nitrogen fertilizers. Forage legumes can fix 50-150 lbs. (or more) of nitrogen from the air, depending on the density of the legume stand. Clover plantings are often most successful when planting in late winter to early spring (February and early March), so it is time to get this on your mind.
Clovers and most other legumes require neutral pH and proper soil phosphorus and potassium. Hopefully you have been following Extension recommendations and soil testing and correcting pH and soil fertility issues when fertilizers are cheaper. If you are considering planting clovers, you should first soil test the sites you are considering planting.
Clovers do not fixate nitrogen as well in acidic soils, so a pH greater than six is a must. If pH, phosphorus and potassium are adequate or easily corrected in some sites but not others, plant clovers in the better sites. Then, grass should be grazed or mowed closely; the reduction in plant residue enables good seed to soil contact for better germination and seedling survival.
Frost seeding of clovers is very cheap and effective. To do this, simply broadcast seed onto the soil surface and allow the freeze and thaw cycles to incorporate it into the soil through frost heave. Success can be enhanced by dragging pastures after you broadcast the seed to get better contact with the soil. If using a no-till drill, be sure the seed depth is right. These small seeds should not be planted more than half an inch deep. Planting equipment should be calibrated to ensure the correct seeding rate. Red clover should be planted at 10-12 lbs. per acre, but white clover should only be planted at 3-5 lbs. per acre.
Using a high-quality seed of a clover species adapted to your site is also of great importance. Arrowleaf clover is highly productive in sandy loam soils, while red clovers prefer loam to clay loam soil, but neither thrives in poorly drained soils. White clover does well in poorly drained loam to clay loam soils.
In some recent research, interseeding white and red clovers into bermudagrass was compared to bermudagrass fertilized with zero, 50, or 100 lbs. of actual nitrogen per acre. For each pound of nitrogen, steer gain per acre was increased by 1.2-1.5 lbs., which would cost about 56 cents/pound of gain. Including clovers in the pasture increased total body weight gain per acre by over 150 lbs. over fertilized pastures, so clovers can be highly cost effective to add to your pastures. — Paul Beck, Oklahoma State University Extension beef cattle specialist
