Salinity patterns in irrigation systems, a threat to be demystified, a constraint to be managed: field evidence from Algeria and Tunisia
Formes de salinité en systèmes irrigués, une menace à démystifier, une contrainte à gérer : études de cas en Algérie et en Tunisie
Abstract
Salinity problems induced by irrigation are often presented in the literature as a threat that can only be managed at the irrigation scheme scale by installing subsurface drainage. On the other hand, salinity is a constraint that has often been successfully managed locally by farmers adapting their practices. However, the continuing expansion of irrigation with related water scarcity problems plus the increasing use of groundwater of marginal quality has resulted in a new challenge that is difficult to handle at the farm level only. To assess the dynamics of soil salinity and water quality together with farmers' salinity management practices, we adapted a common approach to analyze two contrasted salinity patterns: a traditional salinity pattern in an oasis (Fatnassa, Tunisia), and a recent sodicity pattern in a large irrigation scheme (Lower Chelif, Algeria). This approach which combines surveys on farmers' perceptions and practices and salinity measurements and geochemical analysis paves the way for more integrated management of salinity problems related to water scarcity.