Subsurface irrigation system is one of promising techniques for better valorization of water irrigation particularly in arid and semi-arid regions. This irrigation system is characterized by low, frequent and localized water supplies within the root zone. Researchers conducted in relation to subsurface irrigation are unanimous about its several benefits, which explain its rapid expansion across the world. However, its implementation in Tunisia is still very limited. In order to identify the performance of subsurface irrigation system (SDI) under arid conditions of southern Tunisia, a comparative experimental study (between this system and the drip irrigation system (DI)) was conducted within the experimental station of the Institute of Arid Regions-Chenchou (Gabes), in a potato plot. The experimental protocol consisted of eight treatments:
a)- Two treatments with the DI system : T1 (q = 4 l/h) and T2 (q = 2 l/h).
b)- Six treatments with the SDI system: emitters of different flow rates (4 l/h and 2 l/h) and laterals buried at three depths (10 cm, 15 cm and 20 cm) .
Results show that water content within the root zone was always higher under SDI system and that its fluctuation is especially more restricted than that recorded under DI system. This could explain high irrigation efficiency values recorded with SDI treatments where laterals buried at 15 cm depth's have generated the highest water productivity. However, for laterals buried at 20 cm depth's and with emitters delivering 4 l/h, deep water percolation is more evident. Nevertheless, these results obtained during a single season, are still preliminary and could not be so reliable in order to give suitable recommendations on the appropriateness of this irrigation technique, but support to carry on these trials under other conditions (other soil types, different crops and other climates) of Tunisia.