How Effective Are Existing Phosphorus Management Strategies in Mitigating Surface Water Quality Problems in the U.S.?

Abstract

Phosphorus is an essential component of modern agriculture. Long-term land application of phosphorous-enriched fertilizers and animal manure leads to phosphorus accumulation in soil that may become susceptible to mobilization via erosion, surface runoff and subsurface leaching. Globally, highly water-soluble phosphorus fertilizers used in agriculture have contributed to eutrophication and hypoxia in surface waters. This paper provides an overview of the literature relevant to the advances in phosphorous management strategies and surface water quality problems in the U.S. Over the past several decades, significant advances have been made to control phosphorus discharge into surface water bodies of the U.S. However, the current use of phosphorus remains inefficient at various stages of its life cycle, and phosphorus continues to remain a widespread problem in many water bodies, including the Gulf of Mexico and Lake Erie. In particular, the Midwestern Corn Belt region of the U.S. is a hotspot of phosphorous fertilization that has resulted in a net positive soil phosphorous balance. The runoff of phosphorous has resulted in dense blooms of toxic, odor-causing phytoplankton that deteriorate water quality. In the past, considerable attention was focused on improving the water quality of freshwater bodies and estuaries by reducing inputs of phosphorus alone. However, new research suggests that strategies controlling the two main nutrients, phosphorus and nitrogen, are more effective in the management of eutrophication. There is no specific solution to solving phosphorus pollution of water resources; however, sustainable management of phosphorus requires an integrated approach combining at least a reduction in consumption levels, source management, more specific regime-based nutrient criteria, routine soil fertility evaluation and recommendations, transport management, as well as the development of extensive phosphorus recovery and recycling programs.