December 2008
Forage Matters

Legumes in Fescue

Surveys have shown we have over 1.1 million acres of tall fescue in Alabama, most of which is the variety ‘Kentucky 31.’ "Fescue" is an extremely useful forage grass, but it is not without its drawbacks. Although it comes as close to being a year-round forage crop as any we can grow in Alabama, mid-summer production and forage quality are poor. Added to this is the fact that most of our fescue is infected with the fungus (Neotyphodium coenophialum), which is known to produce toxins having an adverse effect on livestock gains and reproduction. This fungus is an endophyte (grows inside fescue plants) and is transmitted only by seed.

Scientists continue to seek ways to minimize, counteract or eliminate the adverse effects of the fescue fungus. When planting a new fescue stand, it makes sense to plant a "novel endophyte" grass containing a fungus but that does not produce toxins (at present Max Q is the only such fescue being marketed in the Southeast). However, in an existing toxic tall fescue stand the best approach to reduce fungus effects is to grow a legume with it. Animal performance is typically much better from a legume grass mixture than from infected fescue alone.

Legumes also offer the advantage of fixing nitrogen in association with bacteria on their roots, which has become of major importance in view of recent sharp increases in the cost of nitrogen fertilizer. Because of the current high interest in growing legumes, this article will focus on the species generally the most logical companion species for fescue in Alabama.

White Clover

White clover (including Ladino) is the single-most widely-planted legume in fescue pastures in Alabama. While clover is a true perennial that will normally come back from the roots for several years in areas not excessively droughty. In addition, some varieties also make a good deal of seed that can often result in good reseeded stands. White clover persists best in pastures kept grazed fairly closely, and it can be planted either in autumn or late winter. Suppression of fescue competition by herbicides, tillage or animal hoof action is usually necessary to get good white clover stands in well-established, thick, fescue sods. Crickets may need to be controlled when establishing stands in the autumn.

Red Clover

Red clover is a better yielder than white clover and has a longer growing season, but plants usually live only two years, even under good management and favorable climatic conditions. It is not as tolerant of close grazing as white clover, but will often provide a much greater quantity of forage, especially in summer. Red clover is particularly good to use in a fescue field that will be cut for hay as its upright growth allows it to be much more tolerant of grass competition. Like white clover, it can be planted either in autumn or late winter, and its larger seed size facilitates drilling the seed into existing fescue with a grassland drill. The problems of fescue competition and crickets during establishment also apply to red clover, even though red clover seedlings are stronger.

Annual Lespedeza

There are several varieties of Korean annual lespedeza and two varieties of striate annual lespedeza, a separate but closely related species. The strongest argument can be made for using one of the striate varieties like Kobe or Marion. Annual lespedeza is not a high yielder, but the forage quality is good and the timing of growth is such that it helps "fill in the gap" during hot, dry summers. Annual lespedeza is broadcast-seeded on closely-grazed fescue pastures in early March. Once a good stand has been established, it normally is easy to get reseeded stands. Annual lespedeza fits best in upland fescue pastures too droughty to clover, especially if the pasture will be grazed during mid-summer. Annual lespedeza is also much more tolerant of soil acidity and/or low fertility than most other legumes.

Sericea Lespedeza

Sericea is a summer perennial relative of annual lespedeza and is adapted to similar soil conditions. However, sericea seedlings are weak and slow to grow and therefore difficult to establish in existing fescue pastures unless there is very little fescue or other plants present, or the existing fescue is strongly suppressed with an herbicide. Sericea should be planted in the spring. The easiest and most dependable approach to getting a fescue/sericea lespedeza mixture is to establish the sericea first and drill fescue into it later. Once sericea is established, good grazing management is required to prevent the sericea from being grazed closer than about four inches.

Final Thoughts

 

Annual clovers, alfalfa and several other legumes could be planted into, or at the same time as, fescue and used to advantage, but they are not as good a choice for most situations as the legumes previously mentioned. Growing a legume with tall fescue offers major advantages in the form of better distribution of growth, dilution of the toxins produced by the fescue fungus, improved forage quality and total annual forage yield. Regardless of which species is used, the establishment and management requirements of the legume must be met in order to be successful.

Don Ball is an Extension Forage Crop Agronomist with Auburn University.