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Title: Developing soil erodibility prediction equations for the Rangeland Hydrology and Erosion Model (RHEM)

item AL-HAMDAN, OSAMA - Texas A&M University
item Pierson Jr, Frederick
item Nearing, Mark
item Williams, Christopher - Jason
item HERNANDEZ, MARIANO - US Department Of Agriculture (USDA)
item BOLL, JAN - Washington State University
item NOUWAKPO, SAYJRO - University Of Nevada
item Weltz, Mark

Submitted to: Society of Range Management
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/2016
Publication Date: 1/31/2016
Citation: Al-Hamdan, O.Z., Pierson, F.B., Nearing, M.A., Williams, C.J., Hernandez, M., Boll, J., Nouwakpo, S.K., Weltz, M.A., and Spaeth, K.E. 2016. Developing soil erodibility prediction equations for the Rangeland Hydrology and Erosion Model (RHEM). Presented at the 69th Annual Society for Range Management Meeting, January 31-February 4, 2016, Corpus Christi, TX.

Interpretive Summary:

Technical Abstract: Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by applying piecewise regression analysis to predict the variability of erodibility before and after disturbance (i.e., wildfire, prescribed-fire and tree encroachment) and across a wide range of soil textures as a function of vegetation cover and surface slope angle. The approach combines rain splash, sheet flow and concentrated flow erodibilities into a single parameter for modeling erodibility in most cases. The new approach was evaluated for sites representing different degrees of disturbance associated with burning and tree-encroachment. Our evaluation of the new erodibility approach in RHEM found the method predicts erosion at the plot scale with a satisfactory range of error in all cases. The new approach for estimating erodibility for RHEM has several advantages. First, the results of this study indicate that in most cases the model will be dependent on only one erodibility factor. Second, the approach addresses the phenomenon that erosion rates become larger at a specific threshold point. Third, the equations use readily available data for estimating erodibility values. Fourth, the approach covers continuously a wide range of ground cover and foliar cover.