Title: | Assessing the efficacy of the SWAT auto-irrigation function to simulate irrigation, evapotranspiration, and crop response to management strategies of the Texas High Plains |
Authors: | Chen, Y., G.W. Marek, T.H. Marek, D.K. Brauer and R. Srinivasan |
Year: | 2017 |
Journal: | Water |
Volume (Issue): | 9(7) |
Pages: | |
Article ID: | 509 |
DOI: | 10.3390/w9070509 |
URL (non-DOI journals): | |
Model: | SWAT |
Broad Application Category: | hydrologic only |
Primary Application Category: | irrigation impacts or irrigation BMP scenarios |
Secondary Application Category: | crop, forest and/or vegetation growth/yield and/or parameters |
Watershed Description: | 4.7 ha irrigated field located near Bushland, Texas, U.S. |
Calibration Summary: | |
Validation Summary: | |
General Comments: | |
Abstract: | In the semi-arid Texas High Plains, the underlying Ogallala Aquifer is experiencing
continuing decline due to long-term pumping for irrigation with limited recharge. Accurate
simulation of irrigation and other associated water balance components are critical for meaningful
evaluation of the effects of irrigation management strategies. Modelers often employ auto-irrigation
functions within models such as the Soil and Water Assessment Tool (SWAT). However, some studies
have raised concerns as to whether the function is able to adequately simulate representative irrigation
practices. In this study, observations of climate, irrigation, evapotranspiration (ET), leaf area index
(LAI), and crop yield derived from an irrigated lysimeter field at the USDA-ARS Conservation and
Production Research Laboratory at Bushland, Texas were used to evaluate the efficacy of the SWAT
auto-irrigation functions. Results indicated good agreement between simulated and observed daily
ET during both model calibration (2001–2005) and validation (2006–2010) periods for the baseline
scenario (Nash-Sutcliffe efficiency; NSE >= 0.80). The auto-irrigation scenarios resulted in reasonable
ET simulations under all the thresholds of soil water deficit (SWD) triggers as indicated by NSE
values > 0.5. However, the auto-irrigation function did not adequately represent field practices, due
to the continuation of irrigation after crop maturity and excessive irrigation when SWD triggers were
less than the static irrigation amount. |
Language: | English |
Keywords: | SWAT; evapotranspiration; irrigation magnitude; irrigation frequency; lysimeters; leaf
area index (LAI); crop yield; soil water deficit threshold; single-HRU method |