Viscoelastic Behavior of Vertic Solonetz in the Kamennaya Steppe

Abstract

The aim of this work is to determine viscoelastic behavior parameters of soil pastes and micromonoliths of natric and vertic horizons in the profile of Vertic Solonetz from the Kamennaya Steppe (Voronezh oblast, Russia) and to use rheological properties to explain the formation of three irregular alteration structures with different wavelengths and deformation patterns of the soil mass. The rheological parameters of six soil horizons were determined by the amplitude sweep tests using an MCR-302 rheometer with parallel plates. The general features of viscoelastic behavior of soil pastes and micromonoliths, the correlation between the storage modulus G'_LVR in the linear range of viscoelastic behavior of pastes and micromonoliths with their moisture, the distribution of rheological properties in the soil profile, and the relationship between the content of exchangeable sodium and the integral I_z used for the evaluation of structural stiffness are discussed. Rheological properties of Vertic Solonetz are compared with published data on Vertisols from Brazil, Russia, and USA and on saline clay alluvial soil from Spain. A hypothesis of formation of the profile of Vertic Solonetz with the gilgai microtopography as dependent on the rheological characteristics of the viscoelastic behavior of the studied soil horizons is proposed.