Enhancing on farm and regional irrigation management using MABIA-Region tool

The study represents a diagnostical analysis of the water use at a farm level, which is a necessary step in the development and implementation of strategies to improve the management of irrigation water at an irrigation district scale. The work has focused on a case study, namely the irrigated district of Cherfech located in the governorate of Ariana, 25 km away from Tunis. The analysis concerns 63 farms covering an area of 850 ha during the 2010-2011 crop season. The achievement of this analysis was made possible using the MABIA-REGION software. Thus, daily Penman-Monteith reference evapotranspiration (ET₀), effective precipitation (PE), dual crop coefficients (Kc=Ke+Kcb), potential and actual crop evapotranspiration (ETc and ETa) and net and gross irrigation requirements (NIR and GIR) were estimated for the different study levels (plot, farm and district) using spatially distributed parameters on the climate, crop, soil characteristics, irrigation system, growing season and basic irrigation management practice. These different outputs were also spatially represented using the GIS-Mod tool implemented in MABIA-REGION. The results obtained show that the irrigation´s practice was seasonally variable. Thus, during the winter season, the irrigations practiced was far exceeded the irrigation water requirement estimated by MABIA-Region. While during the summer season, the irrigations carried have merely covered 44% of irrigation water requirements. Also, the study reveals a high variability in the practice of irrigation between different cultures and different farms.