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ARS Home » Pacific West Area » Pullman, Washington » Northwest Sustainable Agroecosystems Research » Research » Publications at this Location » Publication #197963
Title: CURRENT WATER EROSION STUDIES AT PULLMAN, WA., USA

Author
item McCool, Donald
item WU, JOAN - WASHINGTON STATE UNIVERSI
item GREER, R - WASHINGTON STATE UNIVERSI
item SINGH, PRABHAKAR - WASHINGTON STATE UNIVERSI

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/12/2006
Publication Date: N/A
Citation: N/A

Interpretive Summary: More than 80 million ha of cropland in the USA are impacted to some degree by winter hydrology processes, which may include snowmelt runoff, rain on snow, or combined rain and snowmelt runoff and thaw-weakened soils. The USDA's Water Erosion Prediction Project (WEPP) hydrology and erosion model has potential to accurately estimate runoff and erosion from cropland under winter conditions. However, current versions are not successful in dealing with freezing and thawing soil. With the objective of improving winter process modeling, we initiated long-term studies on extensively instrumented experimental plots at the USDA-ARS Palouse Conservation Field Station near Pullman, WA, USA. The study is targeted toward obtaining a better understanding of water movement into and through the soil under freeze/thaw conditions. Two treatments, continuous tilled black fallow and no-till winter wheat after spring barley, provide a wide contrast in management and in runoff and erosion results as well. Instrumentation includes soil water probes and temperature sensors installed incrementally to a depth of 1 m. Weather data include temperature, precipitation, wind speed and direction, and relative humidity. Runoff and soil loss are measured throughout runoff events. These data are currently being used to validate a new energy-based winter process module recently implemented in WEPP. The data can be used in development and validation of other models as well. Results of this study will provide data and information forming the basis for improvements in WEPP and other hydrologic models.

Technical Abstract: More than 80 million ha of cropland in the USA are impacted to some degree by winter hydrology processes, which may include snowmelt runoff, rain on snow, or combined rain and snowmelt runoff and thaw-weakened soils. The USDA's process-based Water Erosion Prediction Project (WEPP) hydrology and erosion model has potential to accurately estimate runoff and erosion from cropland under winter conditions. However, current versions are not successful in dealing with freezing and thawing soil. We initiated long-term studies on extensively instrumented experimental plots at the USDA-ARS Palouse Conservation Field Station near Pullman, WA, USA targeted toward obtaining a better understanding of water movement into and through the soil under freeze/thaw conditions, with the objective of improving winter process modeling. Two treatments, continuous tilled black fallow and no-till winter wheat after spring barley, provide a wide contrast in management and in runoff and erosion results as well. Instrumentation includes soil water probes and temperature sensors installed incrementally to a depth of 1 m. Weather data include temperature, precipitation, wind speed and direction, and relative humidity. Runoff and soil loss are measured throughout runoff events. These data are currently being used to validate a new energy-based winter process module recently implemented in (WEPP). The data can be used in development and validation of other models as well. Results of this study will provide data and information leading to improvements in WEPP and other hydrologic models.