Reducing Phosphorus Losses From Agriculture to Surface Waters Through Manure Management and Use of Industrial by-Products.

Non-point loss of phosphorus (P) from agricultural soils to surface waters is a contributor to eutrophication.  While best management practices (BMPs) that reduce erosion are able to prevent P losses in most situations, such BMPs do little for preventing transport of runoff dissolved P in high P manure-impacted soils.  Many industrial by-products have a strong affinity for P and are able to reduce soluble P concentrations in high P soils and manures, translating to lower dissolved P loads in runoff.  Some materials may also be suitable for direct “filtration” of runoff dissolved P.  Examples of industrial by-products include flu gas desulfurization gypsum, drinking water treatment residuals, and acid mine drainage treatment residuals, which are often obtained for little or no cost.    The discussion will cover the effect of industrial by-product properties on P sorption by high P soils, reductions in manure soluble P levels with material amendments and subsequent impact on P losses in runoff, and the use of materials for directly filtering runoff dissolved P.  The degree and mechanisms of P sorption onto by-products will vary depending on properties such as pH, mineralogy, soluble Ca, and pH buffer capacity, as well as soil and manure properties.