| Title: | Validating soil phosphorus routines in the SWAT model |
| Authors: | Vadas, P.A. and M.J. White |
| Year: | 2010 |
| Journal: | Transactions of the ASABE |
| Volume (Issue): | 53(5) |
| Pages: | 1469-1476 |
| Article ID: | |
| DOI: | 10.13031/2013.34897 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | pollutant only |
| Primary Application Category: | phosphorus cycling/loss and transport |
| Secondary Application Category: | model equations, functions and/or source code |
| Watershed Description: | Field study data from approximately 40 studies in multiple countries. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | Phosphorus transfer from agricultural soils to surface waters is an important environmental issue. Commonly used
models like SWAT have not always been updated to reflect current understanding of soil P transformations and transfer to
runoff. The objective of this study was to validate the ability of routines in both SWAT2000 and SWAT2005 to initialize the quantity of P in different soil P pools (and thus soil total P) and simulate changes in the simulated solution P pool. Based on data from 40 published studies, results show that currently published equations to estimate the soil PSP parameter and SWAT's method of summing four soil P pools underpredict soil total P. An underprediction of soil total could result in underprediction of P loss in runoff with eroded sediment. Conversely, the proposed alternative for estimating soil total P, which includes a new equation to estimate the soil PSP parameter and includes the solution P pool when summing soil P pools, resulted in accurate predictions of soil total P for 484 topsoil samples from 35 published studies. Results also show that both the SWAT routines and the routines proposed by a previous study for simulating changes in soil P were able to accurately predict long‐term changes in soil solution P. However, routines in both SWAT2000 and SWAT2005 may underpredict solution P for several weeks after P is added to soils. This could result in underprediction of dissolved inorganic P loss in runoff soon after a P application to soils. The routines proposed by the previous study would not result in similar underpredictions. |
| Language: | English |
| Keywords: | Modeling, Phosphorus, Soil, SWAT |