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Updated: Jul 19, 2026
10:49
Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
Estimating source coefficients for phosphorus site indices.
H A Elliott1, R C Brandt, P J A Kleinman
1Dep. Agricultural and Biological Engineering, The Pennsylvania State University, University Park, PA 16802, USA. hae1@psu.edu
Journal of Environmental Quality
|October 31, 2006
Summary
Phosphorus release to runoff varies widely. This study developed a method to estimate P source coefficients (PSCs) using water-extractable P (WEP) content, improving P loss predictions from land-applied organic materials.
Area of Science:
- Environmental Chemistry
- Soil Science
- Agricultural Engineering
Background:
- Phosphorus (P) release to runoff from land-applied organic sources is highly variable.
- Existing P site indices use generic P source coefficients (PSCs) that do not fully account for this variability.
Purpose of the Study:
- To develop a method for estimating source-specific PSCs based on the water-extractable P (WEP) content of organic amendments.
- To improve the accuracy of P loss predictions in P site indices.
Main Methods:
- Correlated runoff dissolved P (RDP) with WEP using data from seven published rainfall-runoff studies.
- Developed an empirical equation to calculate PSCs from WEP values.
- Validated the computed PSCs in two independent runoff experiments.
Main Results:
- A strong correlation (r² = 0.80) was found between RDP and WEP for surface-applied manures and biosolids.
- An empirical equation [PSC = 0.102 x WEP(0.99)] was developed for estimating PSCs.
- Using computed PSCs significantly improved correlations between P loss and loading rates (r² = 0.73–0.86) compared to generic PSCs (r² = 0.45–0.48).
Conclusions:
- WEP content is a reliable indicator of the runoff enrichment potential of organic P sources.
- Source-specific PSCs derived from WEP enhance the predictive capability of P site indices.
- This method can help identify vulnerable sites and inform P loss management strategies.
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