Water movement and salt leaching in drained and irrigated marsh soils of southwest Spain

Abstract

The Guadalquivir River Marshes in southwest Spain, are situated in a former estuary that has now been drained. They cover some 140 000 ha. Soils formed in this zone are alluvial, very clayey, salinesodic, and of vertic character with a shallow, very-saline water table. An area within these marshes, reclaimed in 1979, is the object of this detailed study which looks at some physical and chemical properties of soil, and also the influences of sprinkler and furrow irrigation on drainage and salt leaching. Water movement in this soil is characterized by an initial rapid phase, due to the soil fissures and cracks, followed by a second slow one controlled by the soil matrix. The efficiency of irrigation in salt leaching was higher in the case of furrow irrigation (16 g of salt leached per litre of applied water) than in the case of sprinkling irrigation (10 g l-1), owing to the use of more water in the latter.