Phosphorus and the Chesapeake Bay – Lingering issues and emerging concerns for agriculture

Authors: Kleinman, Peter; FANELLI, ROSEMARY - Us Geological Survey (USGS); HIRSCH, ROBERT - Us Geological Survey (USGS); Buda, Anthony; EASTON, ZACHARY - Virginia Tech; WAINGER, LISA - University Of Maryland; BROSCH, CHRIS - Delaware Department Of Agriculture; LOWENFISH, MARTIN - Natural Resources Conservation Service (NRCS, USDA); COLLICK, AMY - University Of Maryland Eastern Shore (UMES); SHIRMOHAMMADI, ADEL - University Of Maryland; BOOMER, KATHY - Nature Conservancy; HUBBART, JASON - West Virginia University; Bryant, Ray; SHENK, GARY - Us Geological Survey (USGS)

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2019
Publication Date: 8/15/2019
Citation: Kleinman, P.J., Fanelli, R.M., Hirsch, R.M., Buda, A.R., Easton, Z., Wainger, L., Brosch, C., Lowenfish, M., Collick, A., Shirmohammadi, A., Boomer, K., Hubbart, J., Bryant, R.B., Shenk, G.W. 2019. Phosphorus and the Chesapeake Bay – Lingering issues and emerging concerns for agriculture. Journal of Environmental Quality. 1-13. https://doi.org/10.2134/jeq2019.03.0112.
DOI: https://doi.org/10.2134/jeq2019.03.0112

Interpretive Summary: The restoration of the Chesapeake Bay, America’s largest estuary, involves an unprecedented watershed mitigation program that has seen roughly $2 billion in federal and state investment in recent years. As the Chesapeake Bay TMDL moves into its final phase, we evaluate progress to-date, identifying areas of success and concern. A recent uptick in dissolved phosphorus concentrations in many agricultural tributaries highlights concerns related to legacy phosphorus stored in soils and reservoir sediments, phosphorus in artificial drainage and stormwater from hotspots and converted farmland, manure management and animal heavy use areas, and critical source areas of phosphorus in agricultural landscapes

Technical Abstract: Hennig Brandt’s discovery of phosphorus (P) occurred during the early colonization of the Chesapeake Bay. Today, P, an essential nutrient on land and water alike, is one of the principal threats to the health of the Bay. Despite significant reductions in P loadings to the Chesapeake Bay following the implementation in 2010 of a Total Maximum Daily Load (TMDL) regulation, P load reductions across the Bay’s 166,000-km2 watershed have been uneven, and dissolved P loads have increased in a number of the Bay’s tributaries. Having passed the midpoint of the 15-yr TMDL process, some of the more stubborn sources of P must now be tackled. For non-point agricultural sources, strategies that not only address particulate P but also mitigate dissolved P losses are essential. Lingering concerns include legacy P stored in soils and reservoir sediments, mitigation of P in artificial drainage and stormwater from hotspots and converted farmland, manure management and animal heavy use areas, and critical source areas of P in agricultural landscapes. While opportunities exist to curtail transport of all forms of P, greater attention is required toward adapting P management to new hydrologic regimes and transport pathways imposed by climate change.