Writer: D'Lyn Ford
LAS CRUCES - New Mexico State University researchers are finding that during these parched days, reducing grazing intensity to about 25 percent of the available forage annually produces better plants and actually puts more money in ranchers' wallets.
"When it comes to range livestock production, less can be more," said Jerry Holechek, an NMSU range scientist. "I think that conclusion shocks a lot of people, but it's true."
Holechek emphasized that the reductions aren't so much in terms of cattle numbers. Rather it is balancing animal numbers with the available forage supply, determined by clipping and measuring selected range plots in fall surveys. The findings are based on 10 years of research at the university's 64,000-acre Chihuahuan Desert Rangeland Research Center and 32 scientific publications by the NMSU range science team.
The rate or intensity of grazing is a big factor in determining the health and productivity of New Mexico's rangeland. In the past, New Mexico's overgrazing problems typically occurred in periods of drought, Holechek said. More than 90 percent of New Mexico, about 84 million public and private acres, is considered rangeland.
Conventional wisdom suggested that in terms of grazing, more intensive was supposedly better. But Holechek found that continuous, conservative grazing, which involves far lighter use, is actually more profitable and gives higher livestock production than moderate or heavy grazing. Moderate is when about 50 percent of the grass is eaten each year.
Conservative grazing appears to be advantageous over moderate grazing from a beef production standpoint because of the sustainability of the cow herd, said Milton Thomas, a cattle geneticist with NMSU's Agricultural Experiment Station. Moderate grazing systems are more sensitive to variability in rainfall, so with more cows, forage supplies on a ranch are depleted faster than if the ranch was stocked conservatively when drought occurs, he said.
"The ranch manager has fewer grazing options when drought occurs and often has to liquidate the entire herd," Thomas said. "Part of the herd could have been sustained if the ranch was stocked conservatively. It's a difficult balance between covering ranch cost and maintaining enough animals to support the infrastructure of a ranch."
The range research is supported by NMSU's Agricultural Experiment Station and funded by the U.S. Department of Agriculture.
As a result of the range research program, NMSU's Extension professionals have reached out to New Mexico's ranching community with educational efforts aimed at moving grazing rates to conservative or light levels.
"We've seen quite a difference in grazing management in the last few years," Holechek
said. "What's impressed us this time around is the amount of residual vegetation that ranchers are leaving, compared to the drought we had in the mid-1990s." Now and during that rough patch, many New Mexico ranchers liquidated their herds, he said.
Drought conditions have severe, long-term consequences for the state's rangelands, he said. This is especially true for certain soil depths, which more easily allow intrusion of damaging brush species like mesquite. "These deep, sandy soils are very prone to invasion, particularly in droughts," Holechek said. "As brush becomes established, it's very difficult to bring the valuable range grasses back."
Many of NMSU's grazing projects focus on long-term sustainability of New Mexico's rangeland. Some projects have been underway for more than 40 years, including a seasonal use versus conservative, continuous grazing project under the direction of Reldon Beck, an NMSU range scientist emeritus.
In large acreage pastures in the Chihuahuan Desert, Beck found that cattle would rotate within a pasture throughout the year to find the tastiest forage. He also determined that grazing can exacerbate the effects of drought, making grazing management critical in New Mexico's semiarid climates.
Thomas stressed that the size of NMSU's research ranch brings numerous advantages for range scientists, including control of experiments and treatments. The 64,000-acre research center, located 20 miles north of the main campus, features diverse vegetation, soil and land types.
The Chihuahuan Desert Rangeland Research Center, known for many years as the College Ranch, dates back to 1927, when the U.S. Congress granted land to what was then the New Mexico College of Agriculture and Mechanic Arts for research and educational purposes. Since then, additional land has been acquired and the research range now encompasses roughly 100 square miles, from the Rio Grande flood plains on the west to a portion of the DoZa Ana Mountains on the east.
In addition to the studies at the NMSU research ranch, Holechek's range experiments have been replicated on both public and privately owned ranges across the state.
In the future, Holechek said his research would focus on refining New Mexico's range management practices. "We've pretty well answered the question of which is better - light or moderate grazing," he said. "What we're looking at now is, 'How light can you go?' Because the drought risk is so high on these arid lands and cattle prices so variable, you want to stock as lightly as you can and still be income oriented."
© 2013 New Mexico State University Board of Regents
NMSU - All About Discovery!