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United States Department of Agriculture

Agricultural Research Service

Research Project: EROSION PREDICTION TECHNOLOGY TO ENHANCE CONSERVATION PLANNING

Location: Land Management and Water Conservation Research

Title: Winter Hydrological and Erosion Processes in the U. S. Palouse Region: Field Experimentation and WEPP Simulation

Authors
item Singh, Prabhakar - WASHINGTON STATE UNIV
item Wu, Joan - WASHINGTON STATE UNIV
item Mccool, Donald
item Dun, Shuhui - WASHINGTON STATE UNIV
item Lin, Chun-Shu - CHUNG-HUA INSTITUTION
item MORSE, JOHN

Submitted to: Vadose Zone Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 22, 2008
Publication Date: May 21, 2009
Repository URL: http://hdl.handle.net/10113/31401
Citation: Singh, P., Wu, J.Q., McCool, D.K., Dun, S., Lin, C., Morse, J.R. 2009. Winter Hydrological and Erosion Processes in the U. S. Palouse Region: Field Experimentation and WEPP Simulation. Vadose Zone Journal 8:426-436.

Interpretive Summary: Soil erosion by water is detrimental to soil fertility and crop yield as well as to the environment. For cold areas, knowledge and understanding of winter hydrological processes is essential for developing models that can serve as predictive tools. These models can be used to evaluate alternative land-use and management practices for reducing soil loss and protecting land and water resources. A study was undertaken to: (1) evaluate the effect of two contrasting tillage practices on winter hydrological and erosion processes; and (2) assess the suitability of WEPP (Water Erosion Prediction Project) model with an energy-based winter routine for quantifying the field-observed winter processes. Erosion research plots with two treatments: continuous tilled bare fallow (CTBF), and continuous no-tillage seeding of winter wheat after spring cereal (NT), were established at the USDA-ARS Palouse Conservation Field Station near Pullman, WA. The plots were continually monitored for runoff, erosion, soil temperature and water content, and depths of snow and soil freeze-thaw during October to May of 2003–04 through 2006–07. The NT plots generated negligible runoff and erosion whereas CTBF plots produced substantially greater runoff and excessive erosion. Further, frost occurred more frequently and was deeper in the CTBF treatment, likely due to its lack of residue and resulting shallower snow depth. The modified WEPP model successfully reproduced major winter processes (e.g., snow and frost depths, runoff and erosion). However, it can not yet represent all the complicated winter interactions observed in the field. Further research will improve the ability of WEPP to properly account for soil freeze-thaw and transient soil hydraulic properties and hydrologic and erosion processes.

Technical Abstract: Soil erosion by water is detrimental to soil fertility and crop yield as well as the environment. For cold areas, knowledge of winter hydrological processes is critical to determining alternative land-use and management practices for reducing soil loss and protecting land and water resources. Adequate understanding of these processes is also essential to developing models that can serve as cost-effective predictive tools. The objectives of this study were to: (i) evaluate winter hydrological and erosion processes as affected by two contrasting tillage practices; and (ii) assess the suitability of WEPP (Water Erosion Prediction Project), a physically-based erosion model with a newly implemented energy-budget-based winter routine, for quantifying the field-observed winter processes. Long-term erosion research plots subject to two tillage treatments: a control, continuous tilled bare fallow (CTBF), and continuous no-tillage seeding of winter wheat after spring cereal (NT), were established at the USDA-ARS Palouse Conservation Field Station near Pullman, WA. The plots were continually monitored for runoff, erosion, soil temperature and water content, and depths of snow and freeze-thaw during October to May of 2003–04 through 2006–07. Field data showed that NT plots generated negligible runoff and erosion whereas CTBF produced substantially greater runoff and excessive erosion. Further, frost occurred more frequently and was deeper in the CTBF treatment, likely due to its lack of residue and shallower snow depth, compared to the NT treatment. The modified WEPP model could reasonably reproduce major winter processes (e.g., snow and frost depths, runoff and erosion). Yet it cannot represent all the complicated winter phenomena observed in the field. Continued efforts are needed to further improve the ability of WEPP to properly account for soil freeze-thaw and thus transient soil hydraulic properties and hydrologic and erosion processes.

Last Modified: 8/27/2014
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