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Texas Agriculture Archive

March 17, 2006

Damages can occur if
pastures grazed too soon

Grazing too early this year could perform the 'coup de grace,' further damaging already stressed bermuda-grass pastures, said a Texas Cooperative Extension expert.

Beset by drought and wildfires, north central Texas producers may be tempted to turn cattle into their bunch grasses or coastal and Tifton85 bermudagrass pastures as they green up from recent rains.

But don't "jump into pastures" just yet, cautioned Dr. Yoana Newman, Extension forage specialist based at the Texas A&M University System Agricultural Research and Extension Center at Stephenville.

"Just because they green up, doesn't mean pastures have recovered," she said. "The green color is accentuated by the dark color of the burnt ground giving the impression that there is more herbage than there actually is. Whether they have bunch grasses or sod-forming coastal or Tifton85, they need to allow more time to ensure restoration of the sugar reserves that foster growth before the animals graze the pasture again."

Though bermudagrass pastures should recover with proper management, they have been severely stressed. But to graze these north central Texas pastures now might further damage the stands, especially those of ranchers who did not de-stock their pastures, Newman said.

At particular risks are pastures burnt by wildfire, she said. The ash left from the fire only provides a temporary boost of plant nutrients. So with a few inches of rain, the green-up process is accelerated, Newman said.

Most native bunch grasses propagate through seed production, but sod-forming bermudagrass stands can recover and fill in open spots from their below-ground reserves stored in roots and rhizomes (underground stems) and from sugars in the stubble.

This characteristic makes bermu-dagrass highly resistant to both drought and wildfire.

But after such events, "plant reserves become more critical for long-term recovery," Newman said. "For full recovery from stress, overgrazed bermudagrass needs a certain amount of time to build back reserves."

In the initial green-up stage, the plant pulls reserves from both rhizomes and stubble to form new leaves. If the stressed plant is grazed during this stage, before it can replace some nutrient reserves via photosynthesis, there is a danger of depleting the rhizome reserves.

Newman made the following recommendations:

•Wait longer than usual before turning cattle into pastures. Bermudagrass stands should be at least 8 inches tall before grazing.

•Collect soil samples now if you have not done so already, and base pasture fertilization on soil test results.

•Wait until the nighttime temperature reaches 60° F for several days in a row before fertilizing.

"Fertilizing too early will be the equivalent of 'fertilizing weeds' since warm-season grasses are still dormant when nighttime temperatures are below 60° F," Newman said.

•Wait until rain is forecast, and target fertilization until just prior to a rain.

•Control weeds when moisture is present.

"Moisture is necessary for many herbicides to work properly and to be translocated inside the weed plant."

Farmers may be "out of feed and grazing the green-up is very attractive," she said. But buying hay for a few more weeks will more than offset the potential damages and expenses (such as weed control, replanting, etc.) that will result from grazing too early.

"Delaying grazing now, controlling your weeds and fertilizing your pastures will translate into solid summer pastures," Newman concluded.