Genesis, properties and management of salt-affected soils in the Flooding Pampas, Argentina

Abstract

The Flooding Pampa is a plain, covering around 90,000 km2 composed of eolian and alluvial deposits. It is characterized by its geomorphology, with low (0.1-0.01%) slopes and elevations, including the coastal flat. A significant fraction of the region has permanent or temporary lagoons, generally connected with the underground water. Two kinds of water excesses are distinguished: (i) waterlogging of low duration and intensity and (ii) floods, intense and prolonged. Most soils have developed from loessial and loessoid sediments. They are composed mainly of a pyroclastic volcanic association, with a variable proportion of plagioclases, quartz, volcanic glass, lithoclasts and heavy minerals. However, the soils of the East sector of the region were generated by the influence of the sediments from the Rio de la Plata. They show a higher proportion of kaolinitic, smectites and interstratified expansible clays, than other soils of the region. Most salt-affected soils of the region belong to the US Soil Taxonomy Orders of Mollisols, Alfisols, Entisols and Vertisols. Their limitations are not easy to reverse technically and from the economic and ecological point of view. Conversely, it is reasonable to introduce management and reclamation technologies adapted to those limiting conditions.