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Prediction of Bioavailable Phosphorus Loss in Agricultural Runoff
Author(s) -
Sharpley Andrew N.,
Smith S.J.
Publication year - 1993
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1993.00472425002200010004x
Subject(s) - surface runoff , eutrophication , environmental science , bioavailability , water quality , phosphorus , agriculture , particulates , surface water , environmental chemistry , hydrology (agriculture) , nutrient , environmental engineering , chemistry , ecology , biology , bioinformatics , geotechnical engineering , organic chemistry , engineering
The loss of bioavailable P (BAP) in both soluble (SP) and participate (BPP, bioavailable particulate P) forms in agricultural runoff, can accelerate the eutrophication of surface waters. Bioavailable P represents P that is potentially available for algal uptake. Although prediction of BAP loss would provide a more reliable assessment of the impact of agricultural management on surface water eutrophication than just SP or total P (TP), currently no predictive equations are available. Bioavailable P transport in soluble and particulate forms in runoff from 20 agricultural watersheds in the Southern Plains over a 5‐yr period, was predicted using kinetic and enrichment ratio approaches, respectively. Measured and predicted SP and BPP concentrations of individual runoff events were similar for all watersheds and management practices over a range of 7 to 3522 and 3 to 4059 µ g L −1 , respectively. Calculated as the sum of SP and BPP, BAP loss in runoff was predicted accurately, with only a 12% error in measured mean annual loss (662 g ha −1 yr −1 ). Although BAP loss below 100 g ha −1 yr −1 was underestimated, above this value measured and predicted values closely followed a 1:1 relationship. Inclusion of these equations in comprehensive water quality models will improve the prediction of agricultural management on the biological response of receiving water bodies.