Studies in the rheology of natural aqueous dispersions (soils and their mineral substrates) as well as the approaches to control rheological parameters of these systems are of the prime importance to progress in the modern agricultural technologies, geoengineering, construction, etc. To advance in these fundamental and applied directions both original processing of the experimental results and search for the promising modifying agents are required. In this paper, rheological behavior of a representative range of virgin and modified aqueous soils, quartz sand and clays was studied. Modification of the above aqueous dispersed systems with polyelectrolytes and their complexes provided variation of the basic viscoelastic parameters corresponding to the linear viscoelastic region (initial storage modulus G(0)', initial loss modulus G(0)'', and strain gamma(0)) and to the transition to steady-state flow (storage modulus G(in)' and strain gamma(in)) within 1 - 2 orders of magnitude. For samples studied, correlations for these mechanical characteristics were found - with the growth in the values of G(0)' and G(0)'', the increase in the values of G(in)' and decrease in the values of gamma(0) and gamma(in) were observed. Based on these correlations the master curves for the strain dependences of storage and loss modulus as well as for loss tangent were constructed. The appearance of the master curves reflected the unified regularities of the rheological response of dispersed systems which were attributed to the general features of structural evolution caused by the mechanical loading. Procedure for prediction of the rheological behavior of aqueous soil samples based on the experimental measurement of only two experimental characteristics (initial values of storage and loss modulus G(0)' and G(0)'' respectively) was proposed. The validity of this approach was tested using independent experimental data. The original approach obtained can be used for express analysis of the rheology of natural aqueous dispersed materials.