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United States Department of Agriculture

Agricultural Research Service

Title: Improved Watershed Modeling of Phosphorus Loss from Agricultural Lands: a Hydropedological Approach

Authors
item Bryant, Ray
item Gburek, William
item Veith, Tameria
item Hively, W - CORNELL UNIV.

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 2004
Publication Date: March 10, 2006
Citation: Bryant, R.B., Gburek, W.J., Veith, T.L., Hively, W.D. 2006. Perspectives on the potential for hydropedology to improve watershed modeling of phosphorus loss. Geoderma. 131(3-4):299-307.

Interpretive Summary: Hydropedology is a recently coined term to describe multidisciplinary research that combines knowledge and skills from among the disciplines of hydrology and soil science. Although it is attracting much interest, research funding opportunities in hydropedology and the degree of commitment among scientists to furthering research in this area will depend on whether or not hydropedology provides unique advantages for addressing problems of practical concern. We propose that watershed scale modeling of phosphorus (P) loss from agricultural lands is one example of a high priority research area where this kind of multidisciplinary approach is needed and can have major impact. Excessive P loss from agricultural lands has been identified as a major threat to water quality. Watershed modeling is the commonly accepted approach for providing the link between our understandings of field-scale processes of P loss and the environmental impact on some water body of interest. However, current watershed models, which were developed to predict the response of stream flow to rainfall events, have serious limitations for use in predicting the source and amount of P loss from the landscape. We identify some common problems with current models and possible research approaches to address them. Improved watershed modeling as applied to nutrient loss and water quality issues affords both challenges and opportunities for hydropedology.

Technical Abstract: If hydropedology is to emerge as a new discipline or be recognized as an important interdisciplinary work group, it must provide unique advantages for addressing problems of practical concern. This paper presents perspectives on the potential for hydropedology to improve watershed modeling of nutrient loss as it affects water quality. Predicting nutrient loading to surface water bodies requires accurate partitioning of infiltration and runoff from potential source areas, and portrayal of linkages between source areas and surface water bodies to reflect spatial landscape relationships. Calibrating watershed models to the hydrograph at the mouth of a watershed does not necessarily reflect accurate partitioning of runoff among hydrologic response units (HRUs), and default values for HRUs are often a poor representation of reality. Hydropedology represents the combination of knowledge and skills from among the disciplines of hydrology, pedology, and soil physics that are required to address this problem. While there are untapped data and existing knowledge within these disciplines that can be brought to bear, there is also a need for additional interdisciplinary studies. Issues that affect process modeling at field, farm, subcatchment and watershed scales need to be addressed through combined knowledge of the structure of the system as related to the specific objective of better linking runoff generation from potential source areas to surface water bodies. Improved watershed modeling as applied to nutrient loss and water quality issues affords both challenges and opportunities for hydropedology if scientists are willing to bridge disciplines, scales, and data to address current limitations.

Last Modified: 10/21/2014
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