Abstract

PASTRAN, Graciela et al. Aeolian and hydric dynamic in the Medanos Grandes system, SE San Juan, Argentina. Multequina [online]. 2011, vol.20, n.1, pp.15-26. ISSN 1852-7329.

In psammophilous systems the most important ecological factors are the sand movement and water disponibility. In this paper is described the aeolian and hydrical dinamism in crests and inter sand-dunes in the Medanos Grandes system (San Juan), analyzing the aeolian sand movement, volumes of sand removal by hydric erosion registered in erosion registered in canvas and by topographic and geophysic studies determining the soil profile of humidity. In crests domain aeolian processes, without nebkhas formation and with differences in sand movement according to plant cover. For the studied period, in crests with plant cover less than 5% sand movement was -0,361 m³/m (agradation), while -0,017 m³/m when plant cover was up to 35%. These environments showed resistivities between 5000 and 6000 O.m, belonging to less 0.6 g water/100 g sand, in the first meters of depth. In inter sand-dunes variations in both net depositation and aeolian erosion, for the studied period, was 0.032 m³/m, while the water (hydric) mean erosion rate was 0.184 m³/year. On the other hand, resistivity values between 500 and 700 O.m were detected to 5 m deep, belonging to a wet bulb (isolated capillary water) with values 1.21 to 2 g water/100 g sand.

Keywords : Erosion; Wet bulb; Isolated capillary water; Psammophilous system.

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