By Jake Landers
Published June 2013
A rancher who depends on Hairy tridens, Red grama, and Texas grama for forage production for livestock is on the road to poverty. They are the first to recover from a drought, usually from remnants of a root system, but also from seeds produced even during the worst drought conditions. They survive because they are small enough to avoid grazing by cattle, and the close nibbling by sheep doesn’t take a killing amount of leaves.
They are tenacious on bare soil, surviving temperatures dozens of degrees above that of the air. A tenth of an inch of rain can saturate their roots or at least keep them alive until something more comes along. They grow almost anywhere there is a soil from a few inches to 3 feet deep, unless more vigorous plants are there to overtop them. They are considered pioneers in plant succession on overgrazed rangeland or beaten out pastures, eventually to be replaced by taller and more competitive plants.
Texas grama is a giant compared with the other two, yielding maybe 500 pounds of grass per acre in a year. Hairy tridens and Red grama are doing well to reach 50. One animal unit of grazing requires 26 pounds per day which means that a standard-size cow would have to graze off all Hairy tridens or Red grama on one-half acre per day to get adequate nutrition. But I’ve already said that these grasses grow too short for a cow to graze—but they can still be trampled. Sheep and goats can graze close enough to get the 50 pounds per acre.
Rain alone does not bring about a better ground cover. Before the bare ground can fill in with sod-forming grasses like Buffalo and Curly mesquite and better ones like Sideoats grama and Silver bluestem, raindrops, despite their overall benefit, can do damage to the soil. The impact of raindrops disrupts the clumped particles of soil and carries the fine particles away in its runoff. It has been determined that 300 pounds of grassy material per acre is necessary to protect the soil from raindrop damage. Livestock must be restricted from grazing to keep 300 pounds of grass per acre to protect the soil.
Texas grama looks a bit like a stunted Sideoats grama, the champion grass of our rangeland and the State Grass of Texas. The scientific name of Texas grama is Bouteloua rigidiseta. Hairy tridens has leaves less than 2 inches long with white margins. Once classified with taller plants in the Tridens genus, it is now classified as Erioneuron pilosum, but we still keep the old common name. Red grama is another poor relation of Sideoats, yet it has some appealing beauty when the red of its seed heads show up in the sun. Its scientific name is Bouteloua trifida.
If your pastures are overly endowed with the poverty three, you might start easing into a new occupation before you lose too much soil and run out of supplemental feed money.
It’s a long road to recovery—even when it rains.
Reading The Landscape
A typical roadside scene in the Edwards Plateau in April with many wildflowers, even in a dry spring. How do you explain the narrow strip of Old Plainsman (Woolly White) on the shoulder and not any in the rest of the roadside or pasture? —JL
|See below for Jake's answer|
Jake’s comments: Old Plainsman establishes each winter from seed and persists as a rosette accumulating in a thick taproot whatever moisture is available. When the weather warms up it sends up a flower stalk, makes more seeds, and dies. Here it received moisture running off the pavement that didn’t reach the rest of the roadside, but in the pasture, no matter how much moisture, the rosettes cannot survive the grazing by livestock and deer because they are nutritious and so palatable. —JL