Sustainability assessment of traditional, intensive and highly-intensive olive growing systems in Tunisia by integrating Life Cycle and Multicriteria Decision analyses

Olive cultivation is the most important agro-ecosystem in the Mediterranean basin. Despite the remarkable intensification of this system (i.e., the use of high tree densities and large amounts of inputs), the environmental and socio-economic impacts of this transformation have been poorly studied to date. For this purpose, an integrated Life Cycle Sustainability Assessment framework is developed to assess the life cycle sustainability of innovative olive farming systems (intensive and highly-intensive) compared to traditional ones (conventional and organic) in Tunisia, one of the world's leading olive oil producers. The methodological framework consists of two parts: Life Cycle evaluation of olive systems (calculation of impact categories) and Muticriteria Decision Analysis integration (calculation of a sustainability score for each olive system). The results of the Multicriteria Decision Analysis indicate that stakeholders assign the highest priority to environmental aspects, followed by economic and social ones, especially, in the water resource depletion, internal rate of return, and human toxicity impact categories. According to the Life Cycle evaluation, fertilizers, soil management and harvesting are the agricultural practices with the highest impacts. In terms of sustainability, organic systems achieve better scores per ha and innovative systems per ton. Due to the critical water situation in Tunisia, the results suggest the need of: 1) improving the economic performance of rainfed olive farming systems, being the most prominent, by integrating farmers into cooperatives and encouraging conventional producers to get involved in the organic sector, and 2) mitigating the resource depletion impacts of intensive and highly-intensive systems through innovation based on integrated production (a certified system aimed to reduce environmental impacts derived from the use of chemicals in agriculture through the controlled use of production techniques), and limiting these systems to areas of low ecological vulnerability.