Earth, Wind and Water

Why the Edwards Plateau is not in as much distress as you might have heard.

Compiled By BLAIR FANNIN, KAY LEDBETTER and PAUL SCHATTENBERG

Photograph by Jean WulfsonIt is common knowledge among Texans that the crucial streams of the Edwards Plateau—which supplies fresh water to San Antonio and the Hill Country—are in decline, thanks largely to the increase in woody plants. It turns out that common knowledge is wrong.

In fact, spring flows are twice as high as they were before 1950, according to a recent study by Texas A&M AgriLife.

The Edwards Plateau region of Central Texas is the primary water source for the Edwards Aquifer, which supplies water for San Antonio, San Marcos, New Braunfels and many small towns.

The plateau “was basically converted from grassland to a shrubland after many years of heavy livestock grazing,” says one of the study’s coauthors, Bradford Wilcox, a professor in the Department of Ecosystems Science and Management at Texas A&M University and a Texas AgriLife research scientist.

“What people have forgotten is that in the time period between healthy grasslands and the current shrublands, there was an extended period when the land was quite degraded,” he says. Since 1960, he says, “livestock numbers have declined and the landscape has recovered, although there are now more cedar than in the past.”

The study of the Edwards Plateau is among several research efforts at AgriLife Research and Texas AgriLife Extension related to clean air, water and soil.

Researchers work closely with area producers to identify ways to reduce irrigation and comply with any watering restrictions while preserving crop yield and quality.

For example, AgriLife Research and AgriLife Extension joined New Mexico State University, West Texas A&M University and the U.S. Department of Agriculture’s Agricultural Research Service to conduct a federally funded two-week massive air quality monitoring project at an eastern New Mexico dairy.

Brent Auvermann, an agricultural engineering professor with AgriLife Research and AgriLife Extension in Amarillo, said the campaign collected information on coarse particulate matter, ammonia, hydrogen sulfide and methane. The campaign also collected data on a large class of compounds known as volatile organics, some of which are associated with strongly offensive odors, he says.

The goal was to get baseline data on pollutants coming off a large open-lot dairy, similar to those that are characteristic of eastern New Mexico and the Texas Panhandle, Auvermann says.

“We are interested in how much of these different compounds are being emitted, what are the concentrations, and what exposures are likely to be to humans and animals inside and downwind of an open-lot dairy,” he says.

Research benefiting water and soil conservation from the AgriLife Research and Extension Center in Uvalde has national and international implications, according to Bill Holloway, resident director of the Uvalde center.

“Our research includes developing methods of augmenting aquifers, determining their uniqueness and increasing the efficiency of water taken from them,” Holloway says.

Much of the center’s water conservation efforts focus on crop irrigation, which accounts for most water consumption in Texas and other states. Researchers work closely with area producers to identify ways to reduce irrigation and comply with any watering restrictions while preserving crop yield and quality. The techniques include strip tillage and primed acclimation.

“Strip tilling is a well-established conservation technique for increasing soil moisture and decreasing soil erosion,” says Diane Rowland, a crop physiologist at the center. “Primed acclimation exposes crops to moderate drought stress during early development to help increase tolerance during later development, helping conserve water resources in times of drought."

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