Characteristics of Drought Stressed Tall Fescue Systems
Reduced forage growth, shallow root systems, and overgrazing
- Tall fescue growth slows significantly during the summer months, increasing the risk for overgrazing if cattle remain on tall-fescue based pastures during June through August.
- Overgrazing can cause permanent damage to stands, particularly under conditions of low soil moisture. Past grazing practices will influence the amount of damage due to drought. Overgrazed stands are characterized by reduced top growth and shallow root systems and may lack the ability to provide adequate regrowth when weather conditions are more favorable.
- If dry conditions persist for multiple weeks, avoid grazing of tall fescue to help ensure it is not severely damaged during the warm season, making it likely to produce that much more forage once moisture and temperature conditions improve.
Soil and Water Impacts
- Fescue impacted by drought has weakened root systems and decreased foliage that exposes bare soil.
- Covered soil helps to regulate soil temperature and can reduce additional heat stress to tall fescue under drought conditions.
- Overgrazed stands with shallow root systems increase the risk of soil compaction. Deep root systems are important for improving water infiltration and soil water storage.
- Bare soil is more vulnerable to soil erosion and runoff. Soil runoff can result in pasture nutrient losses that may pollute surface waters.
Grazing Management Practices During Drought
- Reduce stocking rates in pastures (reducing the number of animals per unit land area).
- During late spring, do not graze tall fescue stands below 3 inches to provide adequate leaf area for recovery during rest periods.
- Use rotational stocking to allow pastures time to recover before grazing again. The target height to start grazing in tall fescue pastures is 6 to 8 inches.
- Use an alternative forage system during the summer months such as summer annuals to allow tall fescue systems to rest during periods of slow growth.
- Identify and use an area designated as a sacrifice paddock for animals to relieve grazing pressure on drought stressed forage crops.
- Limit grazing pressure on pasture by allowing animals access to hay or fiber-based supplemental feed rations. Only allow animals access to the pasture area for a certain period of time each day (usually a 4 to 6 hour window per day).
- Apply fertilizer and lime based on recommendations from the AU Soil Testing Lab. Managing soil fertility will provide a better stand that is less susceptible to effects of drought.
Consider the Use of Annual Forages for an Emergency Crop
- Summer annual grasses such as pearl millet, sorghum, sorghum x sudangrass, and crabgrass may provide productive growth during the warm-season months of the year.
- In weakened tall fescue stands where renovation will ultimately be required, overseeding these areas with a summer annual may provide grazing during the summer months.
- Sorghum and sorghum x sudangrass hybrids may be more susceptible to pressure from pests such as the sugarcane aphid.
- Keep nitrogen fertilization rates to 60# N (175# ammonium nitrate) per acre maximum. If rain is forecast and additional growth is possible, a second application of nitrogen can be made.
- In planted, well-fertilized stands of annual grasses, nitrate accumulation may be prevalent. Test forages to ensure that nitrates are below the threshold levels of toxicity for livestock.
- Use temporary electric fencing to properly manage the grazing of summer annual grasses. Begin grazing at a height of 20-24” and rotate off when grazed down to 8-12” of stubble.
Helpful Links and Resources
- ANR-0149 Alabama Planting Guide for Forage Grasses
- ANR-0150 Alabama Planting Guide for Forage Legumes
- ANR-1357 Extending Grazing and Reducing Stored Feed Needs
- ANR-0112 Nitrate Poisoning of Cattle in Alabama
- Timely Information – Dealing with Hot, Dry Conditions in Beef Operations
Prepared by Kim Mullenix, Extension Beef Cattle Specialist, Auburn University, Eve Brantley, Extension Water Specialist, and Audrey Gamble, Extension Soil Scientist, and Kent Stanford, Extension Nutrient Management Specialist.
Picture by James H. Miller, USDA Forest Service, Bugwood.org