Water Accounting for Food Security: Virtual Water and Water Productivity in the Case of Tunisian Olive Oil Value Chain

To achieve food security goals, water accounting seems to be one of the most powerful tools to deal with water scarcity management. Thus, indicators, such as virtual water and water productivity, can be considered complementary rather than competing indicators to assess water demand efficiency use. Water computation is, therefore, a crucial tool to understand the overall tendency of water consumption and to assist the decision makers in their decisional process about water efficiency use in different phases of production. In this perspective, this paper aims to evaluate water use throughout the value chain of the olive oil sector, which is the first strategic agro-industrial sector in Tunisia. This evaluation will be undertaken while taking into account various crucial issues concerning the main two production phases in terms of the importance of water consumption (agriculture and processing phase). In the agriculture phase, the rainfed and irrigated modes will be compared, and in the processing phase, three different processing systems will be evaluated. Thirty surveys with farmers and nine surveys with olive oil mill owners were undertaken in the arid region of Sfax: one of the most important olive oil producers in Tunisia. The results show the importance of the theoretical framework adopted in clarifying the state of water consumption in a strategic sector, such as the Tunisian olive oil sector. In addition, the different calculated indicators highlight the importance of the application of a whole technical package and a controlled and efficient use of water to improve the economic profitability and the necessity to revise the irrigated olive growing extensions’ policies under arid conditions. In addition, in the processing phase, the continuous-two phase system is emphasized as the most relevant system in terms of water efficiency use. This system is proposed to be encouraged by policy makers in future olive mill installations.