Assessing Coastal Plain Risk Indices for Subsurface Phosphorus Loss

Authors

Amy L. Shober, University of Delaware
Anthony R. Buda, USDA Agricultural Research Service
Kathryn C. Turner, University of Delaware
Nicole M. Fiorellino, Chesapeake College
A. Scott Andres, University of Delaware
Joshua M. McGrath, University of KentuckyFollow
J. Thomas Sims, University of Delaware

Abstract

Phosphorus (P) Index evaluations are critical to advancing nutrient management planning in the United States. However, most assessments until now have focused on the risks of P losses in surface runoff. In artificially drained agroecosystems of the Atlantic Coastal Plain, subsurface flow is the predominant mode of P transport, but its representation in most P Indices is often inadequate. We explored methods to evaluate the subsurface P risk routines of five P Indices from Delaware, Maryland (two), Virginia, and North Carolina using available water quality and soils datasets. Relationships between subsurface P risk scores and published dissolved P loads in leachate (Delaware, Maryland, and North Carolina) and ditch drainage (Maryland) were directionally correct and often statistically significant, yet the brevity of the observation periods (weeks to several years) and the limited number of sampling locations precluded a more robust assessment of each P Index. Given the paucity of measured P loss data, we then showed that soil water extractable P concentrations at depths corresponding with the seasonal high water table (WEP_WT) could serve as a realistic proxy for subsurface P losses in ditch drainage. The associations between WEP_WT and subsurface P risk ratings reasonably mirrored those obtained with sparser water quality data. As such, WEP_WT is seen as a valuable metric that offers interim insight into the directionality of subsurface P risk scores when water quality data are inaccessible. In the long term, improved monitoring and modeling of subsurface P losses clearly should enhance the rigor of future P Index appraisals.

Document Type

Article

Publication Date

7-20-2017

Notes/Citation Information

Published in Journal of Environmental Quality, v. 46, no. 6, p. 1270-1286.

Copyright © American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

This is an open access article distributed under the terms of the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Digital Object Identifier (DOI)

https://doi.org/10.2134/jeq2017.03.0102

Related Content

Supplemental material is available online for this article.

Repository Citation

Shober, Amy L.; Buda, Anthony R.; Turner, Kathryn C.; Fiorellino, Nicole M.; Andres, A. Scott; McGrath, Joshua M.; and Sims, J. Thomas, "Assessing Coastal Plain Risk Indices for Subsurface Phosphorus Loss" (2017). Plant and Soil Sciences Faculty Publications. 131.
https://uknowledge.uky.edu/pss_facpub/131