Comparison between Different Approaches to Estimating Nutrient Balances in Livestock Production Watersheds

Nutrient budgets have been historically developed on livestock farms to improve nutrient use efficiency and reduce field losses. There is growing interest in developing nutrient budgets, particularly for nitrogen and phosphorus, on larger spatial scales such as watersheds and river basins to guide water quality improvement efforts. A big obstacle to developing such budgets is the lack of access to management practices on individual farms. On the other hand, publicly-available data for larger spatial scales, such as survey and census data compiled by the U.S. Department of Agriculture, is typically aggregated to the county or state level. There is a need for a methodology that reliably estimates nutrient budgets in individual watersheds across different production conditions. This study investigates the potential of incorporating spatial data products to refine estimated nutrient budgets. Three different approaches for nutrient budget development will be evaluated across different watersheds, HUC-10 level. Sources of uncertainty in the developed nutrient budgets will be assessed and their respective contribution to the overall budgets will be quantified.

Corresponding Author

Sharara Mahmoud, North Carolina State University, m_sharara@ncsu.edu

Other authors

Horacio aguirre-villegas, University of Wisconsin-Madison

Rebecca Larson, University of Wisconsin-Madison

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