The southern Mediterranean region displays remarkable diversity and heterogeneity, reflected in the dynamic mosaic of farms and farming systems that have evolved to adapt to the frequent scarcity and irregularity of water availability. Using the Echraf irrigated area in northern Tunisia as a case study, this paper addresses the decision-making process of farmers regarding crop choice and management practices. Drawing from 15 years of real land use data and interviews with experts from the local administration and farmers' associations, we identified the main cropping systems and analysed the determinants of farmers' decision-making, with a focus on tomato production system. The results highlight the nuanced influence of different factors on farmers' decision-making processes. The regional distribution of processing facilities underscores the broader decision-making dynamics and competitive pressures faced by farmers.