Control of Salinity

Abstract

Salinity is a threat to the sustainability of many agricultural systems and especially for irrigated areas in arid and semi-arid zones. Besides the possible specific toxicity the main effect of salts is the reduction of soil osmotic potential causing an effect similar to that of water deficit. The expected yield under saline conditions can be calculated with a simple model whose parameters are the threshold ECe and the yield loss per unit increase in ECe. The salt balance equation allows us to deduce soil salinity based on the EC of the irrigation water and the leaching fraction. The Leaching Requirement is calculated taking into account the irrigation frequency, the EC of the irrigation water and the desired ECe. The presence of Sodium deteriorates soil structure but the effect depends on other factors, in particular the salinity of irrigation water. The reclamation of saline soils is performed by salt leaching while sodic soils are usually reclaimed adding gypsum and leaching Na.