Commercial fertilizers are the most costly input for warm season grass forage production for hay and pastures. With high fertilizer prices there is increased interest in utilizing legumes to offset the cost of nitrogen. Here are some facts that you need to keep in mind when deciding whether or not to introduce cool season legumes into your forage system:
Arrowleaf Clover
- Clovers are cool season legumes with the ability to fix atmospheric nitrogen as a result of their symbiotic relationship with Rhizobium Specific Rhizobium inoculant is required for each clover species. Although most clover seed has been pre-inoculated and sold as pelleted seed, one should always confirm that inoculation has occurred. Otherwise, N-fixation will be very reduced to even non-existent.
- There are several species and cultivars of clovers adapted to different locations in TX. Soil type and drainage are the primary factors that can influence the adaptability of species to a location in a vegetational region. The WebSoil Survey is a valuable resource that can be used to learn more about the soil characteristics of your property. Examples are as follows. Dixie crimson and Apache arrowleaf clover are good choices for sandy or sandy loam upland soils in east Texas but neither of these species are adapted to high pH soils of central Texas. White clover will provide late spring and early summer grazing in either east or central Texas but must be planted on bottomland sites with good moisture availability in winter and spring. Hairy vetch and medics are good choices for upland sites in central Texas.
- Legumes are generally more sensitive than forage grasses to nutrient deficiencies and low soil pH. Successful legume production in pastures depends on maintaining adequate levels of phosphorus (P) and potassium (K) with a soil pH of at least 6.0. Even though N fertilization is not required, fertilizers containing P and K may be needed to maintain productive and persistent stands. Without adequate P and K or when grown in acid soils, legume stands will be unproductive and unreliable.
- The full potential N-fixation and contribution of clovers to the subsequent production of warm season grasses is only accomplished if the grazed plant material is returned to the soil and by grazing livestock via excreta. This returns over 80% of the consumed nutrients by feces and urine. If the clover crop is removed from the pasture as hay, haylage or silage, the clover N contribution is decreased.
- Management strategies for clovers and legumes may fit well into a natural re-seeding with hay harvest for example. Re-seeded clovers provides the opportunity for earlier grazing in the winter-spring and also reduces costs related to new seeding each year.
Vanessa Corriher-Olson, Ph.D.
Professor, Forage Extension Specialist
Soil & Crop Sciences
Overton, TX
Texas A&M AgriLife Extension Service
Monte F. Rouquette, Jr.
Professor, Forage Physiology
Soil & Crop Sciences
Overton, TX
Texas A&M AgriLife Research
Gerald R. Smith
Professor, Legume Breeding
Soil & Crop Sciences
Overton, TX
Texas A&M AgriLife Research