ABSTRACT
Eutrophication, the unwanted growth and die off of aquatic weeds and algae, is a major water-quality concern worldwide. Its economic impact on the fishing and water-treatment industries, in the eastern United States alone, have amounted to $2 billion in 10 years. Over the last 30-40 years, attention has centered on agriculture as the primary source of P loss to surface waters with P being a limiting nutrient for eutrophication. This attention is due to the identification and mitigation of point sources, and the intensification and specialization of farming. However, at the same time, as mitigating point sources of P losses, more than twice as much P has been applied to agricultural land than removed in crop grain or produce. Now many farms possess soil P concentrations well in excess of plant needs, resulting in an increased potential for loss. For the impact of P loss to be minimized, mechanisms must be understood and management must be adjusted accordingly.
