The Eco-Efficiency of Castor Supply Chain: A Greek Case Study

Castor is a candidate crop that grows in marginal lands in the Mediterranean area. It can be grown by utilizing minimal resources to provide unique industrial chemicals or to serve as an energy crop. However, it can be also cultivated with intensive inputs providing higher yields. Whether a high input or a low input scheme is more sustainable depends on the economic and environmental impacts of each case. The objective of the present study, therefore, was to evaluate these impacts under the Mediterranean climate and farming conditions by examining two alternative scenarios: a castor crop grown on a low-inputs field vs. a crop grown in a high-inputs one. The environmental impacts were estimated by following a Life Cycle Assessment (LCA) methodology based on GHG emissions. Furthermore, a sensitivity analysis was performed by switching the functional unit from 1 Mg of castor oil to 1 hectare. The economic feasibility of the castor crop production was assessed by calculating the gross margin, which is referred to the difference between revenues and the variable costs due to the agricultural phases. In addition, the ratio between gross margin and GWP (Global Warming Potential) emissions was applied to calculate the economic performance (gross margin) per unit of environmental burden. Findings showed that the castor oil produced by high inputs resulted in a more sustainable scenario due to its higher yield than low-inputs ones. On the other hand, sensitivity analysis showed that the field management with low inputs showed GHG emissions that were 27% lower than those emitted from the field management with high inputs. Moreover, from an economic point of view, by switching the field management from low inputs to high ones, the Gross Margin increased by about 73%. Finally, the high-inputs scenario showed the best ratio between economic performance and GHG emitted into the atmosphere.