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The Central Ebro Valley, one of the most arid regions of Europe, has one of the longest histories of continuous and sustainable irrigation within Europe. Despite this sustainable outcome, the further expansion of irrigation into areas that have less favorable soil conditions produces unfavorable results and environmental problems. A representative soil toposequence of currently rainfed agricultural land, located very close to El Basal protected area, has been characterized in order to get information on the soils and to assess their capacity to be irrigated. The studied toposequence comprises three different landforms, a structural platform, a depression, and a step which links them; in these landforms soil profiles were described, analyzed, and classified using standard methodologies.

The soil properties and their stages of pedogenic evolution are closely related to their topographic position. Petric Calcisols on the structural platform and Leptic Regosols on the step, bath with very shallow rooting depth, give way to a series of salt-affected soils in the depression, such as Hypersalic Solonchak or Salic Solonetz. These severely salt-affected soils, which are included in irrigation plans, have the severe potential to limit agricultural management and plant production; moreover, their proximity to the protected area of El Basal, which includes a saline wetland, is inadvisable due to the probable changes in water and nutrient cycles. For these reasons, a buffer zone around the protected area is proposed. Moreover, the soil toposequence shows a great pedodiversity that should be considered as adding value to the recognized biodiversity of El Basal area.