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Quantifying Legacy Phosphorus Using a Mass Balance Approach and Uncertainty Analysis
Author(s) -
Mittelstet A.R.,
Storm D.E.
Publication year - 2016
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/1752-1688.12453
Subject(s) - environmental science , watershed , phosphorus , poultry litter , fertilizer , litter , hydrology (agriculture) , agriculture , nutrient , population , soil conservation , soil water , agronomy , ecology , soil science , biology , materials science , demography , geotechnical engineering , machine learning , sociology , computer science , metallurgy , engineering
Classic agricultural‐conservation practices may not address decades of phosphorus (P) accumulation, known as legacy P. Identifying and quantifying legacy P sources are necessary to identify the most cost‐efficient conservation practices. A method was developed to identify and quantify legacy P at the watershed scale using a mass‐balance approach and uncertainty analysis. The method was applied to two nutrient‐rich watersheds in northeast Oklahoma and northwest Arkansas. Each P import and export to and from the two watersheds was identified and quantified using a probability distribution and uncertainty analysis. The P retained in the soils, reservoirs, and stream systems were estimated from 1925 to 2015. Over 8.5 and 6.1 kg/ha/year of P were added to the Illinois River and Eucha‐Spavinaw watersheds with 53 and 55% from poultry production, respectively. Other major historical sources were attributed to human population and commercial fertilizer. Though currently the net addition of P in the watersheds is small due to the export of approximately 90% of the poultry litter, historically only 14‐19% of all P imported to the Illinois River and Eucha‐Spavinaw watersheds was removed via the reservoir spillways, poultry litter, and food exports. The majority of the retained P is located in the soil, 3.6‐5.8 kg/ha/year, and stream systems, 0.01‐3.0 per ha/year.