Submitted to: "Aginfo 99" Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 14, 1999
Publication Date: October 1, 1999
Citation: Sharpley, A.N., Gburek, W.J., Kleinman, P.J. 1999. Phosphorus and nitrogen indices for site-specific environmental risk assessment. "Aginfo 99" Conference Proceedings. p. 1-15. Technical Abstract: Integrated approaches to derive BMPs that accommodate the spatial variation in phosphorus (P) and nitrogen (N) loss from agricultural land are examined using simple P and N indexing systems. We show that the primary flow pathways and critical source areas of P and N loss differ. We demonstrate that BMPs are more effective if narrowly targeted to watershed areas where the source and transport factors governing P and N loss coincide. Current legislation that focuses on source controls alone (e.g. soil P concentrations) may prove unnecessarily restrictive and may not achieve the desired reduction in nutrient loss from non-point sources.