Geomorphology and superficial parameters: the interaction for soil development in the Precordillera Oriental of San Juan, Argentina

Abstract

The study area is located 25 km northwest of the San Juan city, in a sector of the Precordillera Oriental. The main objective is to evaluate whether the geomorphometric properties and surperficial characteristics of alluvial geomorphic surfaces condition the development and spatial distribution of the soil and vesicular horizons. A digital elevation model was used for geomorphometric analysis and maps derived from it. During the field work, data were collected regarding surface and soil properties on three alluvial units: one of the Pleistocene (alluvial level 3) and two of the Holocene (alluvial level 2 and alluvial level 1). Then a correlation of variables was carried out with the objective of developing a model based on the general relationship between geomorphometric variables (slope, vertical distance to the channel network, wind effect, topographic roughness index), vesicular horizon properties (thickness and texture) and superficial properties (rock and sediments covers). The soils analyzed show the presence of vesicular horizons in ten of the eleven soil profiles. The greatest development of the vesicular horizon requires low values of slope and roughness and its greatest development occurs in the oldest levels linked to high values of rock cover, wind effect and vertical distance to the channel network.