Warm-season grasses have a unique place in forage systems for livestock, and the USDA’s Natural Resources Conservation Service encourages ranchers to seed their grazing lands with warm-season grasses when applicable.

“Your goals, such as increased forage or wildlife habitat, will ultimately determine the type and amount of species to plant but if used and managed properly, native warm-season grasses can offer many benefits,” says Rich Wynia, Plant Materials Center manager in Manhattan, Kansas.

Warm-season grasses provide pasture and hay for livestock forage, wildlife habitat and vegetation to filter sediment and nutrients.

Plus, they can be aesthetically pleasing and stabilize the soil. With proper management, these grasses may also increase the fertility and health of the soil.

Like the name suggests, warm-season grasses grow the most and produce the most forage during the hot, mid-summer months when cool-season grasses are less productive or dormant.

This seasonality of growth helps create a continual production of high-quality and high-quantity forage needed to support livestock-based programs. While they are not the answer for all ranches, they can certainly be an asset to many livestock producers.

Soil limitations such as fertility and moisture are not as critical with warm-season grasses as with cool-season grasses.

“Warm-season grasses have root systems that are deeper, making them more tolerant to drought,” Wynia says. “And they fare well in a variety of places with different soils and climates.”

Certain warm-season grass seeds are chaffy and require special machinery for planting. Producers should work with their local NRCS office or conservation district to make sure they are aware of these special requirements.

Since moisture, timing, weeds and soil fertility impact the seed’s success, NRCS recommends that producers use spring planting into a tilled, firm bed of soil free of weeds.

NRCS recommends 20 to 40 seeds to be planted per square foot, which is equivalent to about 4 to 8 pounds of pure live seed per acre. Use the higher seed rate in areas of higher moisture and in areas of less-than-optimum site conditions, such as poorer-prepared sites or with high weed pressure.

Since native warm-season grasses are adapted to local climate and soils, they require less maintenance than many other grasses.

“Realistically, no fertilizer should be applied during the first year unless the soil is extremely deficient in nutrients,” Wynia says. “The current opinion is that fertilizing newly planted warm-season grasses will do more to increase weed growth than the planted species.”

Chemical weed control can be used during establishment. However, periodic mowing, which opens the area and prevents typical spring and summer weeds from smothering the emerged seedlings, may work just as well.

“A stand of grass of one plant per 2 square feet is considered quite good, and the stand will likely improve further by the following June,” Wynia says.

Evaluate plant densities lower than this, about one plant per every 4 square feet, and decide whether to re-plant or supplemental plant to try to improve the stand, he adds.

A few of the most common and versatile warm-season grasses are big bluestem, indiangrass, switchgrass, eastern gamagrass and little bluestem.

These tall warm-season grasses vary in their ranges of adaptability.  

Table 1 provides more information on each species and cultivars.

It is very important to choose cultivars specifically selected and tested for your area of the country.

Native warm-season grasses are used in many different forage and grazing systems in the U.S. and can help meet the dietary requirements of any class of animal.

Click here or on the image at right to view it at full size in a new window.

Integrating warm-season grasses with cool-season grasses, legumes and forbs helps create a diverse system that can provide quality forage and minimize hay and supplemental feed needs.

If the rancher’s goal is to minimize feed inputs, the grazing system should plan for the class and physiological state of an animal.

“For example, if high-quality forage is needed for gain on stocker cattle, consider prescribed burning to remove old decadent plant material and provide lush new growth and a grazing system that keeps the plants vegetative for a portion of the year,” says Kevin Derzapf, NRCS rangeland management specialist in Weatherford, Texas.

Grazing management strategies should focus on performance of the plants and the animals, avoid over utilization of primary forage species and allow plants time to recover between grazing events. Below are some common grazing strategies.

Continuous grazing
Constant use of a pasture throughout the year or most of the growing season

• Advantages: Less labor and time, minimal capital and animal performance is high with low to moderate stocking

• Disadvantages: Lower stocking rates, less production, uneven or patchy pasture use, pasture deterioration if overstocked, overuse of sensitive areas, and overgrazing and undergrazing plants within the same pasture

Rotational grazing
Stock in one or more pastures allowing at least one pasture to rest for all or part of the year

• Advantages: Optimizes animal performance, increases grazing efficiency and forage utilization over the continuous system, and many times the needed infrastructure is already existing

Intensive grazing
Typically, one herd is moved through multiple pastures and the length of time pastures are rested greatly exceeds the amount of time they are grazed

• Advantages: Maximum forage production and use per acre, weed control through grazing, higher stock densities with less stress on animals, and more forage options because pastures can be rested and grazed more efficiently

• Disadvantages: Requires careful forage monitoring, initial costs are higher because of the need for more fencing and water supplies, water systems are more complicated because of the larger number of paddocks, and requires greatest amount of skill for a manager

“Remember, the key to any rotational grazing system is to maintain adequate leaf area from grazing and allow adequate time for rest and recovery of the plants before the next grazing,” Derzapf says. “And for maximum benefits, ranchers must be knowledgeable of the species of grasses.”

Native warm-season grasses, whether grazed or hayed, have management requirements that vary from region to region.

“When evaluating grazing management practices for the five tall grass species mentioned, the number one concern once they’re established is overgrazing,” says Michael Hall, retired NRCS East Region grazing specialist.

Growing points for these native warm-season grasses are located above-ground. When animals overgraze, grazing below a stubble height of 6 to 8 inches, it causes the plant to pull from carbohydrate reserves to extend a new growing point and re-grow leaves and reduces the soil health.

After a grazing event, a resting period is critical for overall plant growth and maintenance. Also, allowing late-summer regrowth to accumulate prior to frost helps ensure strong, healthy plants for the next growing season.

While all of these grasses can be harvested for hay, switchgrass and eastern gamagrass are the two most common species planted and managed as pure stands for haying or grazing.

Leaving 8 inches of stubble when harvesting these grasses for hay helps ensure the plants’ recovery and aids in drying time by elevating the mowed grass above ground level.

It’s important to note that a photoxic reaction in horses has been related to switchgrass hay, so it is not recommended for horses at this time.

Fire is a major ecological influence in the management of these grasses. Prescribed burning can effectively be used every two to three years to stimulate growth, remove accumulated residue and aid in the control of encroaching brush.

Using prescribed burning in the management scheme requires advance planning in late summer to ensure adequate fuels are present to ensure it burns effectively.

“With the right warm-season grasses and proper management, it’s like a domino effect of benefits. Better grass equals more production, which leads to less supplemental feed and healthier animals with fewer inputs,” Derzapf says.

For more information and help on site preparation, planting, burning and grazing management, visit your local NRCS office.  FG

PHOTO
Hereford cattle grazing little bluestem in Texas. Photo courtesy of Ciji Taylor.

Ciji Taylor
Public Affairs Specialist
USDA-Natural Resources Conservation Service