Field-scale calibration of crop-yield parameters in the Soil and Water Assessment Tool (SWAT)

Sumathy Sinnathamby, Kyle R. Douglas-Mankin and Collin Craige

Agricultural Water Management, 2017, vol. 180, issue PA, 61-69

Abstract: Accurate modeling of crop growth within watershed hydrological models is essential, yet most studies pay little attention to parameterizing crop-growth sub-models or validating their performance. This study evaluated crop sub-model parameters of Soil and Water Assessment Tool (SWAT), a widely used, physically based, hydrological model. Baseline SWAT crop parameters were calibrated at the model hydrologic-response-unit-scale using 10 years of replicated field-scale data at one site and validated using 5 years at a second site for corn and grain sorghum, and new parameters were developed and tested for sweet sorghum (bioenergy crop) using 4 years of unreplicated field data. Calibration of crop yields focused on four parameters: lower harvest index (WYSF), harvest index for optimal growing condition (HVSTI), radiation use efficiency (BIO_E), and maximum leaf area index (BLAI). Calibration improved model performance and resulted in slight changes to SWAT default values for four parameters for corn and sorghum. These results provide important preliminary parameters for modeling sweet sorghum in SWAT; both BIO_E and BLAI were greater than default values for grain sorghum. Calibrated parameters improved model performance in validation of corn but not grain sorghum, which was heavily influenced by drought conditions and possibly other management differences at the validation site. Results of this study support use of site-specific, rather than default or off-site, calibration of crop-model parameters to minimize effects on model performance of different soil, water, and nutrient management conditions. Watershed-specific, field-scale crop-yield calibration methods demonstrated in this study are recommended to reduce the plant-growth-related systematic error component of larger-scale hydrological processes (such as streamflow).

Keywords: Hydrologic modeling; Crop model; Corn; Grain sorghum; Sweet sorghum; SWAT (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (11)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0378377416304103
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:agiwat:v:180:y:2017:i:pa:p:61-69

DOI: 10.1016/j.agwat.2016.10.024

Access Statistics for this article

Agricultural Water Management is currently edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Bibliographic data for series maintained by Catherine Liu ().