Impacts of Herbicide Brush Management on Hydrology and Sedimentation at Walnut Gulch Experimental Watershed

The Walnut Gulch watershed in southeastern Arizona has experienced shrub encroachment that caused erosion and reduced infiltration on grasslands. Researchers at the University of Arizona and at the Agricultural Resource Service conducted an experiment to investigate the effectiveness of herbicide treatments in reducing woody species abundance and their impact to vegetation, runoff, and soil loss. They used field rain simulations, modeling approaches, and assessments of physical landscape attributes across spatial scales. Results indicated an increase in gross cover and a significant reduction in runoff and soil loss on treated sites at both fine and coarse scales.