Submitted to: Dust Aerosol, Loess Soils and Climate Change Meeting
Publication Type: Proceedings
Publication Acceptance Date: 10/11/1998
Publication Date: N/A
Interpretive Summary: The beef cattle industry is by far the largest sector in the Texas agriculture industry. According to the 1996 Texas Comptroller Report, cattle production brings in more dollars than any other Texas agricultural product, including cotton (the second largest agricultural product). The beef cattle industry comprises several components including cattle producers (ranchers), feedlots, and slaughter houses. The cattle ranching component depends upon quality rangelands which in turn depends on factors such as drought, soil conditions, and rangeland fire. Yearly losses of pasture due to fire can have a significant economic impact on cattle producers. In the Southern High Plains, open range is often found in areas where soils are poor or water resources are limited. The loss of grass cover due to fire can leave such marginal land susceptible to wind erosion. Here we investigate the recovery rate of burned rangeland as it evolves from ashes to a completely stable surface protected by vegetation. The results show that apparently minor increases in vegetation can quickly stabilize a surface by increasing the wind speed required to initiate particle motion.
Technical Abstract: If left in a purely natural state, semiarid lands are covered with grass or shrubs and are fully protected from wind erosion. Semiarid lands become potential wind erosion problems when they are altered by agricultural practices that remove the vegetative cover. For example, when grasslands are converted to croplands, the natural vegetative cover is often plowed under and the bare soil surface is exposed to the wind. Rangeland, on the other hand, is left in a more natural state and despite grazing pressures there is often sufficient vegetative cover to protect the surface against wind erosion. Occasional rangeland fires, however, can quickly and effectively remove vegetative cover and transform stable rangeland to a highly erodible state in a matter of minutes. Such a rangeland fire exposed a sandy soil surface located in the Portales Valley near Sudan, Texas on Dec. 6, 1996. We set out to monitor wind erosion within this burned rangeland setting at different times of the year as the vegetation slowly grew back. The results show that small changes in vegetation can quickly transform an unstable surface to a fully stable surface by increasing the wind speed required to initiate aeolian transport.