Soil Hydraulic Properties Determined by Inverse Modeling of Drip infiltrometer Experiments Extended with Pedotransfer Functions

Author(s)

Kotlar, Ali Mehmandoost ^{[1, 2]} ; Varvaris, Ioannis ^[2] ; van Lier, Quirijn de Jong ^[1] ; de Jonge, Lis Wollesen ^[2] ; Moldrup, Per ^[3] ; Iversen, V, Bo

Affiliation

^[1] Univ Sao Paulo, Ctr Nucl Energy Agr CENA USP, Caixa Postal 96, BR-13416903 Piracicaba, SP - Brazil

^[2] V, Aarhus Univ, Dept Agroecol, Blichers Alle 20, DK-8830 Tjele - Denmark

^[3] Aalborg Univ, Dept Civil Engn, Thomas Manns Vej 23, DK-9220 Aalborg - Denmark

• Document type: Journal article
• Source: VADOSE ZONE JOURNAL; v. 18, n. 1 JUL 18 2019.
• Web of Science Citations: 0

Abstract

A transient flow experiment using automated drip infiltrometers (ADIs) was performed on soil columns (about 6 dm(3)) large enough to incorporate macro-pore flow effects. We investigated to what extent the estimated soil hydraulic parameters obtained from inverse modeling of these experiments are reliable. A machine learning based pedotransfer function (PTF) for prediction of water content at -1, -10, and -158 m pressure head was developed. Sensitivity analysis of the van Genuchten parameters (residual and saturated water content theta(r) and theta(s), fitting parameters alpha, n, and lambda, and saturated hydraulic conductivity K-s) in soils of sandy, silty, and clayey textures showed that the temporal variation of pressure heads in ADI scenarios was not sensitive to theta(r) and theta(s). The other parameters were accurately estimated from numerically synthesized data. The uniqueness of the estimated parameters did not change when a bias, representing experimental error, was added to the data set. In actual columns, using the temporal and spatial pressure head data from the ADIs and the water contents in the drier range predicted by the developed PTF resulted in a precise estimation of the van Genuchten parameters. Not including the PTF water contents resulted in nonuniquely estimated van Genuchten parameters. (AU)

• FAPESP's process: 16/18636-7 - Mitigation of Nitrate Leaching in Tropical Soils using Layered Double Hydroxide
• Grantee: Ali Mehmandoost Kotlar
• Support Opportunities: Scholarships in Brazil - Doctorate