ABSTRACT

Salinisation of soils has already reduced, or will reduce in the short term, a substantial part of cultivated areas in the world. This phenomenon is due to an excessive accumulation of highly soluble salts (chlorides, sulphates and carbonates of sodium or magnesium) in the surface horizon of soils, which is observed by a reduction in soil fertility (Fig. 8.1). The supply of water to plants is rendered more difficult; some elements may also have a specific toxic effect (Na, Cl, B, Se); sodium may be fixed on clays and concomitantly modify their behaviour in the presence of water. The overall physical properties of soil (permeability) are then degraded.