Shrink-Swell Behavior and Hydraulic Properties of Clay Soils
Some of the most productive agricultural soils contain appreciable amounts of active clay minerals and exhibit shrink-swell behavior in response to changes in soil water content and chemical composition of the soil solution. In addition to myriad of agricultural management and engineering problems associated with changes in mechanical properties and trafficability of such land surfaces, hydrologic predictions of flow and transport processes are seriously hampered due to changes in volume and pore-space geometry induced by clay shrink-swell behavior. The primary objective of this project is to develop a predictive model for hydraulic properties of clay soils that considers changes in volume and pore-space with changing water content and chemical composition of the soil solution. Such model will benefit water management in agricultural fields with
swelling soils, leading to improved infiltration and water use efficiency. Due to the sensitivity of clay soils to irrigation water quality, a framework such as proposed furthermore offers coherent salinity and sodicity management by quantifying the impact of irrigation strategy on soil hydraulic properties. At the extreme end of these considerations are insights on clay dispersion and surface sealing with potential for soil erosion, and colloidal-facilitated transport of agro-chemicals. Finally, elements of the proposed work will also provide new insights for clay liner design for hydrologic isolation of waste disposal sites.