Problèmes de gestion de l'eau d'irrigation et de salinité du sol au sein d’une oasis du sud Tunisien

The oasis and arid zones of the Maghreb are facing major changes related to the modes of governance of water resources, climate change and the dynamics of agrarian systems. When it comes to cash crops such as the date palm in southern Tunisia, farmers tend to provide excessive volumes of water. In this context, poor irrigation management has led to a rise in the surface water table and a phenomenon of hydromorphy threatening the sustainability of the oasis system. The current study presents and discusses the issues for irrigation water management and soil salinity in date palms oasisin southern Tunisia. Farming practices were examined through surveys and participatory workshops with farmers. Also, continuous monitoring of soil water content and salinity was carried out on an agricultural plot using improved surface irrigation.The results show that there have been an excessive irrigations that are largely due to the lack of awareness of farmers of the date palm water needs. Analysis of the saline profiles of the studied plots showed an increase in vertical (intra-profile) and spatial (inter-profile) variability in relation to irrigation frequencies and sand amendment practices, salinity and groundwater depth. The sand amendment technique shows efficiency in the reduction of salinity provided to improve the drainage network and the awareness of farmers of better irrigation management according crop water requirements.