Assessing the hydraulic reduction performance of HYDRUS-1D for application of alkaline irrigation in variably-saturated soils: Validation of pH driven hydraulic reduction scaling factors

Ali, Aram ORCID: https://orcid.org/0000-0003-2986-9220 and Bennett, John McL and Biggs, Andrew A. J. and Marchuk, Alla and Ghahramani, Afshin ORCID: https://orcid.org/0000-0002-9648-4606 (2021) Assessing the hydraulic reduction performance of HYDRUS-1D for application of alkaline irrigation in variably-saturated soils: Validation of pH driven hydraulic reduction scaling factors. Agricultural Water Management, 256:107101. pp. 1-13. ISSN 0378-3774


Abstract

Land application of alkaline irrigation water is an increasing practice in most agricultural lands around the world due to the shortage of freshwater resources. Accurate evaluation of the effects of alkalinity on soil properties is essential to avoid environmental risks. In this study, we used long leaching columns to evaluate alkalinisation and sodification hazards in soils in the laboratory at different water qualities (0, 100, 310 and 650 HCO3-, mg L−1) with electrical conductivity (EC) ≈ 2.1 dS m−1 and sodium adsorption ratio (SAR) ≈ 12 (mmolc L−1)0.5. The ability of the HYDRUS-1D model to simulate solute and water movement under unsaturated conditions in columns of 40 cm height filled with acidic, neutral or alkaline soils was also assessed. Changes in soil EC, SAR, pH and alkalinity were monitored at 5, 15, 25 and 35 cm depths for 290 days. Increased solution alkalinity resulted in increased pH, alkalinity and sodicity within the soil profile, in particular for the soil surface and acidic soils. In general, the HYDRUS model, using the standard hydraulic reduction scaling factor, was able to simulate the effects of alkalinity in the soil profile and the associated hydraulic conductivity reduction. Amending the pH driven hydraulic reduction scaling factor in the model to a non-linear, soil-specific, pedotransfer function significantly improved the correlation between predicted and observed hydraulic conductivity. The findings of this study provide validation for a non-linear approach towards determining the pH hydraulic reduction scaling factor in the HYDRUS-1D model for unsaturated conditions. However, it is noted that further improvement of this non-linear approach is required to incorporate other factors governing soil structural stability.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Sustainable Agricultural Systems (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Sustainable Agricultural Systems (1 Aug 2018 -)
Date Deposited: 08 Aug 2021 23:44
Last Modified: 08 Aug 2021 23:44
Uncontrolled Keywords: Alkalinity; Unsaturated condition; Sodicity; Hydraulic conductivity; Solute movement; HYDRUS-1D
Fields of Research (2008): 05 Environmental Sciences > 0503 Soil Sciences > 050304 Soil Chemistry (excl. Carbon Sequestration Science)
05 Environmental Sciences > 0503 Soil Sciences > 050305 Soil Physics
05 Environmental Sciences > 0503 Soil Sciences > 050399 Soil Sciences not elsewhere classified
Fields of Research (2020): 41 ENVIRONMENTAL SCIENCES > 4106 Soil sciences > 410605 Soil physics
41 ENVIRONMENTAL SCIENCES > 4106 Soil sciences > 410699 Soil sciences not elsewhere classified
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9614 Soils > 961499 Soils not elsewhere classified
Socio-Economic Objectives (2020): 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180605 Soils
Identification Number or DOI: https://doi.org/10.1016/j.agwat.2021.107101
URI: http://eprints.usq.edu.au/id/eprint/43196

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