By Vanessa A. Corriher
During a drought, little can be done to increase forage pasture growth. Proper management, however, can minimize the impacts of a drought on your operation when it does occur. Careful management early in a drought minimizes long-term stand damage and helps maintain forage yields when rains do come.
If pastures are managed properly during times of low moisture, the effects of drought will be less severe and pastures will rebound faster when precipitation is sufficient. Remember that the management practices that minimize damage to pastures during drought are the same practices that maintain healthy pastures in a normal year.
Evaluate herd numbers. Reduce the stocking rate if you believe forage supply will be limited. First, cull cows that are old, open, in poor condition or have poor disposition. A veterinarian can palpate cows for pregnancy and check for health problems that warrant elimination from the herd. Cows that are not pregnant are difficult to justify feeding expensive hay.
Moving cattle to leased grazing lands where forage is available is one option to remove them from stressed pastures without selling off a portion of the herd.
Another option is early weaning and selling of calves. This reduces the stocking pressure and the nutrient requirement of the cows (reducing forage intake by 20%) because lactation is stopped.
The longer that decisions to decrease livestock numbers are delayed, the sooner the forage supply will be exhausted. Delaying the decision to reduce stocking during a drought accelerates the financial losses of the livestock production enterprise.
Protect existing forage. Lack of moisture suppresses plant growth and retards root development. Allow 6" to 8" of new growth before allowing livestock to graze. A healthy pasture will have 3" to 6" of stubble.
In severe drought, pastures may not be able to reach this stubble height, so these pastures should be deferred until the time of dormancy (when nights are 55°F for warm-season grass pastures) and then grazed to 3" to 4" stubble height.
Those pastures that have little or no green growth are living off the roots, and their root mass has already declined substantially. Those roots must be replaced or bare areas will increase and invader grasses and weeds will prevail. In addition, the overgrazing of forage plants removes the buds that are needed for regrowth. If insufficient stubble remains, water capture and infiltration is reduced. So, when it does rain again, less water will enter the soil stores for plant growth.
Stocking rates must be reduced on all types of forage. Fertilizer should be reduced or stopped during periods of reduced precipitation and rotational stocking should be considered to increase harvest efficiency and forage utilization.
Keep weeds out. Don’t apply herbicides during a drought. Plant mechanisms in response to a drought will prevent adequate entry of herbicides into plants. The result: a high-cost application with little control of the specific weed.
Managing for drought must take place throughout the year. Be sure to graze properly in the summer and plan for fall, winter and spring forage production to minimize feeding hay or supplements.
Vanessa A. Corriher is a Texas AgriLife Extension forage specialist located in Overton, Texas.
- October 2011