Mechanisms of the Desertification Process in the Santa María Valley, Tucumán Province (Argentina)

Acta geológica 24 (1-2): 2012

Abstract

Desertification is the greatest environmental challenge facing dry regions, mainly in relation to their productive potential. It is defined as “land degradation in arid, semiarid and dry sub-humid zones as a result of various factors, including climatic vari ations and human activities” (UNCCD, 1994). In this regard, the Santa Maria valley, located in the north-western quadrant of the province of Tucumán and north-eastern of Catamarca, presents a severe picture of land deterioration, with a highly degraded antropic-environmental system, the main causal factors being the heterogeneity of the relief, an arid-semiarid seasonal contrast (with permanent hidric def- icit and seasonal rainfall), surface materials highly susceptible to removal by wind and water, loss or marked decrease in vegetation cover (represented by two ecosystems of arid characteristics, Monte and Prepuna), because of cutting or diverse extractive activities, overgrazing and improper management of soil and water, throughout several centuries. Considering this geoenvironmental and anthropogenic context, this article analyzes the influence of current and past climate variability and cover of vegetation, as factors of desertification. We study the processes linked to the geomorphological mechanism of desertification, such as water erosion, salinization of soils, wind erosion and sedimentation, stoniness (pave- ment), etc. and its influence in the spatial heterogeneity of vegetation and soil.