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Fertilization of Tall Fescue

Posted Jun. 30, 1998

Fertilization of established fescue offers an opportunity for cattle producers to generate inexpensive cool season forage. Fescue has the reputation of being poor quality forage. In fact, a common question of cattle producers is, "How do we get rid of the noxious weed?" Actually the correct question is, "How can we manage fescue to obtain its potential?"

The endophyte1 has successfully been removed from fescue, but the endophyte's removal has proven to make it more vulnerable to adverse weather and improper grazing management. Endophyteinfected fescue has proved to be better adapted to marginal soils and adverse climatic conditions that exist in the Ardmore area.

Since the ergot2 is toxic to cattle and necessary for the fescue to persist, the challenge before us is to manage the fescue plant. The manager must minimize the negative effect of the ergot on livestock, while maintaining the symbiotic relationship of the endophyte within the plant. A challenge, managed through fertilization and grazing techniques.

The endophyte exists in the crown of the infected plant and extends up the stem as seeds develop. It is perpetuated through the seed. The key to fescue forage management in the spring is to keep it from seeding. Without seed production, the ergot should not exist at extremely toxic levels.

The greatest opportunity for desirable forage production from endophyte-infected fescue comes with fall fertilization. Up to 100 pounds per acre of actual nitrogen should be broadcast September 1, with the phosphorus, potassium, and lime as indicated by soil test. The fertilization should stimulate large volumes of cool season forage.

The fescue forage grown in the fall will be mostly leaf and the ergot is usually below toxic levels at this stage of growth. Even though the quality may limit the potential of young cattle, the value of fall and winter grazing cannot be overlooked. Land preparation and seed costs are removed when the perennial plant persists, leaving mostly fertilization costs against the forage produced.

If existing stocking rates require a spring application, be sure to topdress in January or early February. Avoid late top dressings that will generate mostly seed, which creates significant ergot toxicity. During April and May it may be necessary to keep cattle off the fescue during seed formation. By then other forages should be available.

Fescue is not for all ranches. It does offer an opportunity for some to generate inexpensive fall and winter forage for some classes of cattle. Talk to your neighbors about this issue, and you will hear quite different comments. Listen with the understanding of fescue management discussed above. Their comments will usually make sense. Give us a call!

For a more in depth discussion, refer to OSU Fact Sheet Number F-2559

Terms from the article:
1en·do·phyte (`en1de-fit´) is a plant, such as a fungus, growing within another plant.
2er·got (ûr ' gðt, -göt ') is a fungus (Claviceps purpurea) that infects various cereal plants and forms compact black masses of branching filaments that replace many of the grains of the host plant.

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