Recovering pastures after a drought

The southeastern U.S. was affected by drought from July to December of last year. Periods of drought impact pasture productivity in the following season. How pastures are utilized following a drought is equal to or more critical than the way pastures are managed during the time of water stress.

A lack of moisture in the fall, along with cooler weather, may negatively impact plant growth and delay root development.

“Moisture alone does not overcome drought stress and some strategies can be implemented to aid in the recovery process,” says Rocky Lemus, Mississippi State extension forage specialist.

In a recent Mississippi State extension newsletter, Forage News, Lemus suggests to assess soil fertility first. Soil test permanent pastures and hayfields in the spring. Follow soil test recommendations to apply lime and other recommended nutrients. If soil pH requires greater than 1 ton of lime per acre, focus initially on liming the field.

If nitrogen, phosphorus, and potassium are recommended, Lemus suggests splitting the applications, especially with nitrogen and phosphorus in order to improve efficiency.

“Do not fertilize blindly,” Lemus says.

Before any fertilizer is applied to bermudagrass or bahiagrass this spring, be sure the pasture has 80 to 90 percent green up. If root growth needs to be stimulated, focus on adding phosphorus.

Once pastures start to green up, it can be tempting to start grazing immediately. Allowing unlimited access to plants before a stronger root system is developed may further weaken plants and delay forage production and recovery.

If the recovery period is limited by overgrazing, the plant is forced to utilize its stored sugars to grow replacement leaves. This is especially true for warm-season perennial pastures. Do not allow animals to graze the pasture until plants have reached 8 to 10 inches in height. To allow plant recovery and root development, limit postgrazing height to 3 inches.

Under drought conditions, weeds can become more opportunistic and competitive in pastures. Also, pastures are less able to compete with vigorous weeds, especially annual weeds. Scout and identify weeds that have not been encountered in the past and may be toxic to livestock.

“It is very important to develop an aggressive weed control program to reduce competition for moisture and nutrients,” Lemus says.

Do not rush to renovate pastures following a drought, especially for species like bermudagrass that spread rapidly with adequate moisture. Lemus recommends waiting until green up to determine pasture loss and then making a decision whether to renovate. If a pasture has at least one viable plant per square foot, then the pasture will likely recover with appropriate applied nutrients and grazing management.

Pastures with less than 30 percent stand loss should recover quickly with strategic fertility, weed control, and grazing management. Pastures with 30 to 60 percent stand loss will likely achieve full recovery with proper reseeding, fertility, weed control, and conservative grazing management for several months. Stands with over 60 percent loss may require renovation or long rest periods, which may be nine months to a year under favorable weather conditions, for full recovery.

Sydney Sleep

Sydney Sleep was the 2016 Hay & Forage Grower summer editorial intern and is a junior at South Dakota University.