Analysis of models for the correlation between retention and conduction of water in unsaturated soil

• Grant number: 13/14669-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2013
• End date: June 30, 2017
• Field of knowledge: Agronomical Sciences - Agricultural Engineering - Soil and Water Engineering
• Principal Investigator: Quirijn de Jong van Lier
• Grantee: Lívia Previatello da Silva
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated scholarship(s): 14/05930-9 - Analysis of pore space tortuosity and connectivity using CT scans of soil samples, BE.EP.DR

Abstract

The relation between soil water retention and pressure head allows evaluating the distribution of pore sizes of a soil. This distribution, together with knowledge of the pore space tortuosity, allows the prediction of soil hydraulic conductivity as a function of water content or pressure head. Models like those developed by Childs and Collis-George, Burdine and Mualem are based on this principle, treating tortuosity as an empirical parameter. The retention and hydraulic conductivity properties can be simultaneously determined in experiments by the Wind-Schindler evaporation method. This method associated with the use of tensiometers polymers allows determination from near saturation until wilting point conditions. Recent advances in the technique of tomography image analysis now allow 3D visualization of porous media at a micrometer resolution, making possible the direct analysis of pore sizes and connectivity. This research project aims to determine, in a number of soil samples, retention and hydraulic conductivity applying the evaporation method with the use of tensiometers polymers. Results of the standard analysis method will be compared to results obtained by inverse modeling, evaluating the use of Burdine and Mualem models when combined to the most common equation systems. Microtomography will be used for a direct evaluation of pore space tortuosity, and it will be compared to the empirical parameters linked to tortuosity estimated by the models. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

SILVA, Lívia Previatello da. Analysis of hydraulic properties and 3D images of some tropical soils. 2017. Doctoral Thesis - Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) Piracicaba.