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Inverse modelling for predicting both water and nitrate movement in a structured-clay soil (Red Ferrosol)


Kirkham, JM and Smith, CJ and Doyle, RB and Brown, PH, Inverse modelling for predicting both water and nitrate movement in a structured-clay soil (Red Ferrosol), PeerJ, 6 Article e6002. ISSN 2167-8359 (2019) [Refereed Article]


Copyright Statement

Copyright 2019 Kirkham et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.7717/peerj.6002


Soil physical parameter calculation by inverse modelling provides an indirect way of estimating the unsaturated hydraulic properties of soils. However many measurements are needed to provide sufficient data to determine unknown parameters. The objective of this research was to assess the use of unsaturated water flow and solute transport experiments, in horizontal packed soil columns, to estimate the parameters that govern water flow and solute transport. The derived parameters are then used to predict water infiltration and solute migration in a repacked soil wedge. Horizontal columns packed with Red Ferrosol were used in a nitrate diffusion experiment to estimate either three or six parameters of the van Genuchten-Mualem equation while keeping residual and saturated water content, and saturated hydraulic conductivity fixed to independently measured values. These parameters were calculated using the inverse optimisation routines in Hydrus 1D. Nitrate concentrations measured along the horizontal soil columns were used to independently determine the Langmuir adsorption isotherm. The soil hydraulic properties described by the van Genuchten-Mualem equation, and the NO3 adsorption isotherm, were then used to predict water and NO3 distributions from a point-source in two 3D flow scenarios. The use of horizontal columns of repacked soil and inverse modelling to quantify the soil water retention curve was found to be a simple and effective method for determining soil hydraulic properties of Red Ferrosols. These generated parameters supported subsequent testing of interactive flow and reactive transport processes under dynamic flow conditions.

Item Details

Item Type:Refereed Article
Keywords:pedotransfer functions, water flow, Rosetta, Hydrus, soil water, nitrate, Hydrus-1D, Hydrus-2D, leaching
Research Division:Environmental Sciences
Research Group:Soil sciences
Research Field:Soil sciences not elsewhere classified
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Soils
UTAS Author:Kirkham, JM (Mr James Kirkham)
UTAS Author:Doyle, RB (Associate Professor Richard Doyle)
ID Code:131088
Year Published:2019
Web of Science® Times Cited:3
Deposited By:Agriculture and Food Systems
Deposited On:2019-02-28
Last Modified:2020-04-02
Downloads:12 View Download Statistics

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