Legumes have long been viewed as special and beneficial pasture plants, but there is justifiably heightened interest in them at present, thus the reasons for growing them deserve renewed emphasis.
Nitrogen Fixation: When in association with the proper type of bacteria, most legumes can obtain nitrogen from the atmosphere and “fix“ it in nodules on the roots. Nitrogen fixation/acre/year by a stand of annual legume(s), white clover or red clover, and alfalfa often is within the ranges of 50 to 150, 75 to 200, and 150 to 200, respectively.
Forage quality: As compared to grasses, legumes are usually higher in crude protein, digestibility, and minerals and vitamins. The result is better performance of grazing animals in terms of higher gains, milk production, and reproductive rates.
Distribution of Growth: Introducing legumes into grass pastures often extends the grazing season. Red clover is especially likely to provide additional summer production when grown with cool season perennial grasses. Several legumes can extend the grazing season when grown with annual grasses.
Forage Yield: Yield per acre from a grass/legume mixture is often higher than from grass alone, especially if little or no nitrogen fertilizer is applied.
Crop Rotation Benefits: Legumes provide N for succeeding crops, improve soil tilth, and may create root channels that benefit subsequent crops.
Reduced Animal Toxicities: Growing legumes with toxic endophyte tall fescue can reduce fescue toxicity symptoms and improve animal performance. Legumes also contain more magnesium (Mg) than grasses and thus can reduce the likelihood of grass tetany, the underlying cause of which is Mg deficiency.
Environmental Acceptability: Legumes provide slow release nitrogen, which is more environmentally friendly than commercial nitrogen. They also furnish pollen and nectar for bees, tend to increase populations of beneficial predatory insects, and are a preferred food of many wild animals.
Profit: Forage legumes have the potential of simultaneously improving animal performance and lowering costs. Keys to success with successfully introducing and using legumes include selecting the proper legume for a particular site and situation, providing soil amendments as needed, and providing management that minimizes grass competition.
Source: Dr. Don Ball, Dept. of Agronomy and Soils, AuburnUniversity, Auburn, AL