SALTIRSOIL: A simple integrated simulation model for the prediction of soil salinisation in agricultural irrigated well-drained lands

Abstract

SALTIRSOIL (SALTs in Irrigation SOILs) is a soil salinisation model able to make accurate predictions of soil salinity, sodicity and alkalinity at soil water saturation using no more information than that obtained during most regular land surveys. It is a deterministic, static and functional (capacity-type) process-based model composed in turn of two main modules. The first one calculates the soil water balance through the year, and hence the soil solution concentration factor with regard to the irrigation water. Next, the irrigation water major ion composition is multiplied by this factor and then, the second module, called SALSOLCHEM, calculates the major inorganic ion composition of the soil solution at equilibrium with soil calcite and gypsum at the soil CO2 partial pressure. The SALTIRSOIL algorithms were verified by simulating two horticultural crop developments in a fine to medium texture heavily calcareous soil under a semi-arid Mediterranean climate. The quotients of electrical conductivity at saturation to electrical conductivity in the irrigation water were 1.68 and 1.60 respectively. These quotients of EC25 are very close to the value of 1.5 used in the development of FAO guidelines for irrigation water assessment.