Paul Beck, Oklahoma State University Extension Beef Cattle Specialist
Nitrogen fertilizer prices have reached over $750/ton for urea (over 85¢/pound of N), with expectations that it could reach over $1,000/ton. This is a good time to consider using legumes in our pastures to replace N fertilizers. Forage legumes can fix 50 to 150 (or more) pounds 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 were cheaper. If you are considering planting clovers first you should soil test the sites you are considering planting. Clovers do not fixate nitrogen as well in acid soils, so pH> 6.0 is a must. If pH, P, and K 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, seed is simply broadcast seed onto the soil surface and allowing the freeze and thaw cycles to incorporate it into the soil through frost heave. Success can be enhanced by dragging pastures after you broadcasting the seed to get better contact with the soil. If using a no-till drill be sure seed depth is right, these small seeds should not be planted more than ½ inch deep. Planting equipment should be calibrated to ensure the correct seeding rate. Red clover should be planted at 10 to 12 pounds per acre, but white clover should only be planted at 3 to 5 pounds per acre.
Using high-quality seed of a clover species adapted to you site is also of great importance. Arrowleaf clover is highly productive in sandy loam soils while red clovers prefers loam to clay loam soil but neither thrives in poorly drained soils. White clover does will 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 0, 50, or 100 pounds of actual N per acre. For each pound of nitrogen, steer gain per acre was increased by 1.2 to 1.5 pounds, which would cost about 56 cents per pound of gain. Including clovers in the pasture increased total bodyweight gain per acre by over 150 pounds over fertilized pastures, so clovers can be highly cost effective to add to your pastures.
For more information about clovers and other legumes refer to the fact sheet “Forage Legumes for Oklahoma” PSS-2585 by John Caddel and Jim Enis. https://extension.okstate.edu/fact-sheets/forage-legumes-for-oklahoma.html