| Title: | Evaluation of phosphorous site assessment tools: Lessons from the USA |
| Authors: | Sharpley, A., P. Kleinman, C. Baffaut, D. Beegle, C. Bolster, A. Collick, Z. Easton, J. Lory, N. Nelson, D. Osmond, D. Radcliffe, T. Veith and J. Weld |
| Year: | 2017 |
| Journal: | Journal of Environmental Quality |
| Volume (Issue): | 46(6) |
| Pages: | 1250-1256 |
| Article ID: | |
| DOI: | 10.2134/jeq2016.11.0427 |
| URL (non-DOI journals): | |
| Model: | APEX, EPIC, SWAT & SWAT-VSA |
| Broad Application Category: | review/history |
| Primary Application Category: | model and/or data comparison |
| Secondary Application Category: | phosphorus cycling/loss and transport |
| Watershed Description: | none |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | This article was published as part of a Journal of Environmental Quality (Issue 46(1)) Special Section entitled: "The Evolving Science of Phosphorus Site Assessment". The authors also describe using the TBET model but that is actually an interface based on SWAT simulations so TBET is not identified as a separate model here. |
| Abstract: | Critical source area identification through phosphorus (P)
site assessment is a fundamental part of modern nutrient
management planning in the United States, yet there has been
only sparse testing of the many versions of the P Index that now
exist. Each P site assessment tool was developed to be applicable
across a range of field conditions found in a given geographic
area, making evaluation extremely difficult. In general, evaluation
with in-field monitoring data has been limited, focusing primarily
on corroborating manure and fertilizer “source” factors. Thus, a
multiregional effort (Chesapeake Bay, Heartland, and Southern
States) was undertaken to evaluate P Indices using a combination
of limited field data, as well as output from simulation models
(i.e., Agricultural Policy Environmental eXtender, Annual P Loss
Estimator, Soil and Water Assessment Tool [SWAT], and Texas
Best Management Practice Evaluation Tool [TBET]) to compare
against P Index ratings. These comparisons show promise
for advancing the weighting and formulation of qualitative P
Index components but require careful vetting of the simulation
models. Differences among regional conclusions highlight model
strengths and weaknesses. For example, the Southern States
region found that, although models could simulate the effects
of nutrient management on P runoff, they often more accurately
predicted hydrology than total P loads. Furthermore, SWAT and
TBET overpredicted particulate P and underpredicted dissolved P,
resulting in correct total P predictions but for the wrong reasons.
Experience in the United States supports expanded regional
approaches to P site assessment, assuming closely coordinated
efforts that engage science, policy, and implementation
communities, but limited scientific validity exists for uniform
national P site assessment tools at the present time. |
| Language: | English |
| Keywords: | |