Sustainability of agro-livestock integration: Implications and results of Emergy evaluation

This study aims to assess the sustainability of an agroforestry system: i.e. a system obtained by the union of two productions to get at least two by-products from the same productive space. In particular, this case study presents the integration of a goose raising system with an organic grape production, from an environmental point of view. This integration is mainly designed to have two simultaneous co-products (grape and goose meat) with: i) a less intensive use of machineries for weeding and ii) avoiding use of chemical fertilizers and weeding. The sustainability is assessed by means of emergy evaluation. Emergy is a thermodynamic based tool able to estimates the environmental cost of products and services in terms of the solar energy (directly and indirectly) required for its production. As Emergy is not a state function, its final value depends on the way the product is made. The set theory applied to the emergy evaluation enables the comparison between the integrated system and the originating isolated systems in a proper way. Results confirm that the integrated system enables a saving, in emergy terms, amounting to 33% compared to the two originating isolated production systems. Emergy evaluation is able to keep track of the lower amount of resources required from outside the agroforestry system due to the optimization of resources internally available.