Application of SWAT model to investigate nitrate leaching in Hamadan–Bahar Watershed, Iran

▶ We used the Soil and Water Assessment Tool (SWAT) to build a hydrologic model for the Hamadan–Bahar watershed in western Iran. The watershed suffers from an increasing water pollution problem due to agricultural activities. ▶ The hydrology model was calibrated, and validated with uncertainty analy...

Full description

Saved in:
Bibliographic Details
Published in:Agriculture, ecosystems & environment ecosystems & environment, 2010-12, Vol.139 (4), p.675-688
Main Authors: Akhavan, Samira, Abedi-Koupai, Jahangir, Mousavi, Sayed-Farhad, Afyuni, Majid, Eslamian, Sayed-Saeid, Abbaspour, Karim C.
Format: Article
Language:English
Subjects:
Agronomy. Soil science and plant productions
Biological and medical sciences
Calibration
Crops
Freshwater
Fundamental and applied biological sciences. Psychology
General agroecology
General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping
General agronomy. Plant production
Generalities. Agricultural and farming systems. Agricultural development
Groundwater
Leaching
Nitrate leaching
Nitrates
Soil (material)
Solanum tuberosum
SUFI-2
SWAT model
Triticum aestivum
Uncertainty
Watersheds
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:▶ We used the Soil and Water Assessment Tool (SWAT) to build a hydrologic model for the Hamadan–Bahar watershed in western Iran. The watershed suffers from an increasing water pollution problem due to agricultural activities. ▶ The hydrology model was calibrated, and validated with uncertainty analysis. ▶ We used the calibrated hydrology model and further calibrate it for nitrate leaching and crop yield, using wheat and potato. ▶ We characterized the spatial and temporal leaching pattern. ▶ In a follow up work we will suggest a best management practice for the region. Application of large amounts of mineral and organic fertilizers in intensive agricultural regions of Hamadan–Bahar watershed in western Iran contributes to excessive nutrient loads in soils and groundwater bodies. Groundwater supplies approximately 88% of the water consumed in Hamadan. The objective of this study was to investigate the temporal and spatial variability of nitrate leaching in Hamadan–Bahar watershed. We employed the Soil and Water Assessment Tool (SWAT) to model the amount and dynamics of nitrate leaching from a typical crop rotation in this watershed. The SWAT model was calibrated and validated with uncertainty analysis using SUFI-2 (Sequential Uncertainty Fitting, ver. 2) based on measured daily discharge data from 7 hydrometric stations, wheat and potato yield, and measured daily nitrate at the outlet of the watershed. The calibration using crop yield increases the confidence on soil moisture and evapotranspiration. The calibration (R2=0.83, NS=0.77) and validation (R2=0.70, NS=0.70) results were quite satisfactory for the outlet of watershed. Spatial variations in nitrate leaching were also found to agree reasonably well with measured nitrate concentrations in groundwater (73% overlap based on a defined criterion). Also, nitrate leaching was found to be more significant under potato (Solanum tuberosum L.) rotation (254–361kgNha−1year−1), representing 30–42% of nitrogen applied to the soil. About 36% of Hamadan–Bahar aquifer has a nitrate leaching rate higher than 100kgNha−1year−1. The presented model and its results have the potential to provide a strong base for considering different scenarios to reduce nitrate leaching and suggest a BMP (best management practice) in Hamadan–Bahar watershed.
ISSN:0167-8809
1873-2305
DOI:10.1016/j.agee.2010.10.015