Application of Water Vapor Sorption and Spectroscopy for Novel Characterization of Surface and Engineering Properties of Soils

Project: Research

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Soil water vapor sorption and reflectance spectroscopy represent two rapid and cost effective options for determining soil properties such as clay content, nutrient contents, cation exchange capacity, and specific surface area. Currently, mechanisms behind the hysteretic nature of water vapor sorption isotherms is far from understood despite its critical importance in modeling unsaturated water flows and other biological processes. Thus, a mechanistic understanding of hysteresis is one of the aims of the proposed project. Further, soil surface properties such as water repellency are essential for agronomic processes such as plant water utilization, preferential leaching of pesticides and nutrients whereas, other properties like the Atterberg limits and shrink-swell potential are crucial for characterizing soil for engineering applications. Laboratory procedures for these two sets of soil properties are generally tedious, costly, and non-reproducible. The proposed work posits that recent advances in measuring soil water vapor sorption isotherms and the rapidity of near-infra red (NIR) and mid-infrared (MIR) spectroscopy presents an excellent opportunity to develop a framework for determining water repellency and selected engineering properties. Based on a wide range of samples (pure clays, clayey soils, sandy soils, young Greenland soils, expansive and low activity soils, and organic soils), the project combines measured soil water vapor sorption isotherms and NIR/MIR spectra, with (i) clay and organic characteristics to understand hysteresis, (ii) vapor sorption kinetic theory and organic matter fractions to predict water repellency, and (iii) clay type and reference data to develop and validate models to predict several engineering properties. Results will facilitate rapid estimation of the selected properties from easy-to-measure data; assist policy making and research requiring soil surface properties on regional or national scales.
Effective start/end date01/07/201601/10/2020

ID: 129039144