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

TABOADA, M ; DAMIANO, F.; IMBELLONE, P; LAVADO, R.S

Saline and Alkaline soils in Latin America: Natural Resources, Management and Productive Alternatives

Springer

Lugar: Cham; Año: 2020; p. 191 - 208

The Flooding Pampa occupies the Center and East of Buenos Aires province. The area is a plain, covering around 90,000 km2 composed of eolian and alluvial deposits of the Pleistocene. It is characterized by its geomorphology, with low (0.1- 0.01 %) slopes and elevations, including the coastal flat. The hydrology and the drainage system developed on a landscape of flat lowlands with a very low gradient and with no drainage network. A significant fraction of the region has permanent or temporary lagoons of endorheic drainage, generally connected with the underground water. Two kinds of water excesses are distinguished: i) waterlogging of low duration and intensity which takes place regularly at the end of winter and the onset of spring and ii) floods, intense and prolonged, which do not occur in a precise period of the yearMost soils of the whole Pampas 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 Flooding Pampas were generated by the influence of the sediments from the Rio de la Plata. They show a higher proportion of smectites and interstratified expansible clays and a higher proportion of kaolinitic clays, than other soils of the region.Most salt-affected soils of the region belong to the US Soil Taxonomy Subgroups Natraqualfs, Natrudolls, Natraquolls and Natralbolls. Saline Entisols (Aquents) and Vertisols (Aquerts) are also found. Contrary to other agriculturized areas of the Pampas, the region is devoted mainly to cattle husbandry. The limitations imposed by landscape and soils characteristics are not easy to reverse technically and are not affordable from the economic and ecological point of view. Conversely, it is reasonable to introduce management and reclamation technologies adapted to those limiting conditions. The basic principles which guide most of them are: i) to control the capillary rise from the phreatic water; ii) to increase the infiltration rate; iii) to restore or create a plant cover and iv) to improve the physical and chemical soil condition. The technologies differ in their complexity degree