Combining livestock and tree crops to improve sustainability in agriculture: a case study using the Life Cycle Assessment (LCA) approach

Agriculture contributes significantly to GHG emissions and global warming and reducing its environmental impact is fundamental for global sustainability. Extensive rearing systems for poultry production, such as free-range systems, are considered with great interest due to their positive effects on meat quality and animal welfare and health, but their environmental impact is still debated, in part because of the high land-use impacts due to the land requirements for grazing. However, it is possible to combine orchards and animals in the same area, thus eliminating additional land use for grazing. This study investigated the environmental impact of combining free-range poultry and olive orchards using a cradle to gate Life Cycle Assessment (LCA) approach. The impact assessment was developed using the ‘Eco-Indicator 99 method. Feed production was the process with the highest impact on the poultry system (96% and 84% of the total normalized impact, respectively, for poultry inside and outside the orchard). The land-use category had the highest impact, both for the poultry (62 and 67%, respectively, inside and outside the orchard) and for the olive (99 and 70%, respectively, for grazed and non-grazed orchards) systems. Grazing poultry in the olive orchard and eliminating the land use due to grazing (accounted for in the orchard LCA) decreased the land-use impact of the poultry system by 18% and reduced the overall impact by approximately 12%. By providing weed control and fertilization in the orchard, grazing also dramatically reduced the impact of the olive orchard for all of the categories considered, except for land use, which had the highest impact (70%). Therefore, the overall impact reduction with the chickens grazing in orchards was approximately 30%; however, this impact reduction approached 100% if land use was not considered. Additional benefits of combining poultry and orchard that are not considered in the LCA are briefly discussed. Although this was a case study with olives and poultry, the results are applicable to other combinations of livestock and crops, and show that such combinations provide significant reductions in the environmental impacts of agriculture. The results can be useful when developing guidelines to improve sustainability in agriculture.