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United States Department of Agriculture

Agricultural Research Service

Research Project: DISTURBANCE ASSESSMENT AND MITIGATION OF GREAT BASIN RANGELAND

Location: Northwest Watershed Management Research

Title: Hydrologic impacts of soil water repellency on fine-to-coarse-textured soils of wooded shrublands and shrub-steppe communities

Authors
item Williams, Christopher
item Pierson, Frederick
item Kormos, Patrick -
item Al-Hamdan, Osama -

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: September 17, 2009
Publication Date: October 4, 2009
Citation: Williams, C.J., Pierson Jr, F.B., Kormos, P.R., Al-Hamdan, O.Z. 2009. Hydrologic Impacts of Soil Water Repellency on Fine-to-Coarse-Textured Soils of Wooded Shrublands and Shrub-Steppe Communities. In:AGU Chapman Conference on Examining Ecohydrological Feedbacks of Landscape Change Along Elevation Gradients in Semiarid Regions, American Geophysical Union, Boise and Sun Valley, Idaho, October 4-8, 2009.

Interpretive Summary: The potential for soil water repellency to dominate rangeland hydrologic responses has significant implications for ongoing plant community transitions and disturbance regimes. Naturally occurring soil water repellency has been well documented on semiarid rangelands and chaparral plant communities. Soil water repellency occurs in fine- to coarse-textured unburned soils due to the coating of soil particles with hydrophobic compounds leached from organic materials. Burning can induce or exacerbate soil water repellency where volatized hydrophobic compounds are translocated into the soil profile. The hydrologic effects of soil water repellency under unburned conditions are largely dampened by canopy interception, surface retention of runoff, and heterogeneous infiltration patterns. Vegetation and ground cover alterations following disturbance greatly reduce these mitigating effects. We present a culmination of hydrologic data from several sagebrush sites and two pinyon and juniper invaded shrublands under undisturbed and disturbed conditions. We demonstrate how the spatial arrangement of vegetation influences soil water repellency and runoff behavior and present examples of post-disturbance hydrologic responses to vegetation change on water repellent soils. We further show that the temporal variability in the strength of soil water repellency greatly affects hydrologic responses to disturbances.

Technical Abstract: The potential for soil water repellency to dominate rangeland hydrologic responses has significant implications for ongoing plant community transitions and disturbance regimes. Naturally occurring soil water repellency has been well documented on semiarid rangelands and chaparral plant communities. Soil water repellency occurs in fine- to coarse-textured unburned soils due to the coating of soil particles with hydrophobic compounds leached from organic materials. Burning can induce or exacerbate soil water repellency where volatized hydrophobic compounds are translocated into the soil profile. The hydrologic effects of soil water repellency under unburned conditions are largely dampened by canopy interception, surface retention of runoff, and heterogeneous infiltration patterns. Vegetation and ground cover alterations following disturbance greatly reduce these mitigating effects. We present a culmination of hydrologic data from several sagebrush sites and two pinyon and juniper invaded shrublands under undisturbed and disturbed conditions. We demonstrate how the spatial arrangement of vegetation influences soil water repellency and runoff behavior and present examples of post-disturbance hydrologic responses to vegetation change on water repellent soils. We further show that the temporal variability in the strength of soil water repellency greatly affects hydrologic responses to disturbances.

Last Modified: 10/1/2014
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