Texas A&M Agrilife’s Kay Ledbetter reports that team members from Texas A&M University’s ecosystem science and management department and the Texas A&M AgriLife Extension Service are working on a project to determine best range management practices for aquifer recharge.
The “Effects of Brush Removal on Distributed Recharge of the Carrizo-Wilcox Aquifer” project is funded by the Wintergarden Groundwater Conservation District. Water recharge to an aquifer is highly dependent on vegetation and soil type. The researchers are studying the effectiveness of vegetation removal and how different soils respond to the removal, with the objective is to identify the best management practices for landowners to employ to ensure maximum environmental returns and economical livestock and wildlife production.
The research team is led by Texas A&M assistant professor Dr. Jason West and associate professor Dr. Bill Rogers, both members of the university’s ecosystem science and management department, and Dr. Bob Lyons, an AgriLife Extension range specialist in Uvalde,
Ms. Ledbetter quotes Dr. West commenting that land-management techniques being evaluated include prescribed fire and its interaction with chainsaw/herbicide and roller chopping, with a project’s goal being to study how interactions of prescribed fire, commonly utilized mechanical treatments, and dominant recharge zone soil types affect plant community and soil hydrologic processes.
“It is important to understand how these removal strategies impact the plant communities critical to economically viable rangeland enterprises,” Dr. West is cited observing. “Simultaneously, they are comparing the effects of these management strategies on groundwater recharge processes. Natural resource and conservation managers are increasingly being asked to maximize the production and sustainability of multiple environmental services. While research exists comparing the effects of different fire, mechanical and chemical treatments on above-ground and below-ground dynamics, few studies have simultaneously compared the responses of plants, soils and hydrology to these brush-removal strategies.”
Dr. West says such studies are critical if landowners are to decide which strategies are most beneficial in restoring environmental services, and when soil-water recharge is a goal, it is important to document how strategies to increase recharge impact the plant community that is essential to profitable livestock and wildlife enterprise.
Observations of treatment responses have been monitored since spring 2011, and the observation period has included a severe drought with precipitation measured at the project field site from April 2011 through August 2012 being only about 75 percent of normal. The researchers have found using stable water isotopes and soil coring indications that the dominant woody vegetation of the Carrizo-Wilcox aquifer recharge zone accesses soil moisture primarily in the top 6 feet of soil, and rarely access deeper water – perhaps only on coarsetextured soils, and that brush control techniques have significantly different effects on aquifer recharge and both woody and herbaceous vegetation.
Ms. Ledbetter notes that thanks to renewed funding from the Wintergarden Groundwater Conservation District, Dr. West and his colleagues will be able to continue monitoring these responses and assessing impact of the prescribed burns recently completed.
For the full report see:
Contact Dr. Jason West at 979-845-3772, email: jbwest[at]tamu.edu