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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #297735
Title: In-field and edge-of-field chemical barriers to dissolved phosphorus losses

Author
item Bryant, Ray
item EASTON, ZACHARY - Virginia Polytechnic Institution & State University
item Buda, Anthony
item ALLEN, ARTHUR - University Of Maryland Eastern Shore (UMES)

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/27/2013
Publication Date: 11/1/2013
Citation: Bryant, R.B., Easton, Z., Buda, A.R., Allen, A. 2013. In-field and edge-of-field chemical barriers to dissolved phosphorus losses. ASA-CSSA-SSSA Annual Meeting Abstracts. Paper No. 348-16.

Interpretive Summary:

Technical Abstract: Standard vegetative in-field and edge-of field conservation practices, such as grassed waterways, filter strips and riparian buffers, are effective barriers to particulate phosphorus (P) loss in runoff. However, these practices are not as effective at reducing dissolved P losses. In some soils and landscapes, dissolved P losses can equal or exceed particulate P losses making it impossible to achieve TMDL reductions through implementation of standard conservation practices alone. High levels of dissolved P losses are frequently associated with high soil P concentrations resulting from legacy applications of P in excess of crop requirements. In some cases, soils are so over saturated with legacy P that it will require decades of P removal by crop uptake to remediate the situation. Once these conditions exist, changes in field management practices cannot stem the losses over the short term. Chemical barriers to P losses involve the introduction of P sorbing materials, and several approaches have been proposed. Phosphorus sorbing materials provide a metal cation, such as iron, aluminum or calcium, to react with dissolved phosphorus to create an insoluble compound by sorption processes. Reported reductions in dissolved P range from greater than 90% in batch studies to less than 25% in field studies where variable soil conditions and the dynamics of runoff events complicate simple sorption reactions. Chemical amendments have also been proposed for improving flocculation and thereby reducing colloidal P transport to tile drains. This presentation will discuss in-field and edge-of-field chemical barriers that have been proposed as effective means of reducing P losses in surface and ground water, as well as the challenges to their adoption by farmers and action agencies.