Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/29/2005
Publication Date: 3/29/2005
Citation: Coale, F.J., Basden, T., Beegle, D.B., Brandt, R.C., Elliot, H.A., Hansen, D.J., Kleinman, P.J., Mullins, G., Sims, J.T. 2005. Development of regionally-consistent phosphorus source coefficients for use in phosphorus index evaluations in the mid-atlantic region. Symposium Proceedings. p. 1-4. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: The Phosphorus Index was designed as a screening tool for use by soil conservation field staff and nutrient management planners to rank the relative vulnerability of agricultural fields as sources of phosphorus (P) loss to surface waters. Development of individual P Indices in the Mid-Atlantic Region has yielded state-specific versions that differ in specific content and numeric calculation. However, each state P Index incorporates a measure of P solubility or relative availability of P in land-applied nutrient amendments. Our goal was to reach a regional consensus on a common approach and process for incorporating P solubility into state-specific P Index determinations. The Phosphorus Source Coefficient (PSC) represents the relative proportion of the total P applied to the field that is potentially subject to loss with drainage water. The PSC is a quantifiable characteristic of the nutrient amendment and is independent of the characteristics of the soil to which the amendment is applied. Based upon a review of available literature comparing losses of dissolved P in runoff from soils that had been amended with different fertilizers, manures and biosolids, Mid-Atlantic PSC “book values” were developed. These book values will be adopted by all states in the region for five categories of nutrient amendments. In addition, Mid-Atlantic states are working to develop a common approach to quantifying PSC values from a laboratory test that will soon be available to state and commercial testing laboratories. Ultimately, conservation or nutrient management planners who do not wish to rely on book value PSCs will be able to submit nutrient amendments to laboratories to determine a PSC value that is specific to that amendment.