Life cycle assessment of fruit and vegetable production in the Region of Murcia (south-east Spain) and evaluation of impact mitigation practices

The Region of Murcia (south-east Spain) is a world-leading agricultural producer which exports 2.5 million tonnes of fruit and vegetables per year. It holds a leading position in international sales of many fresh products including lettuce, broccoli, lemon, melon and artichoke. However, the sustainability of this highly profitable business is in the spotlight as concerns mount regarding environmental exhaustion caused by intensive farming. To gain a more objective perspective, we present the first quantification of the environmental impacts of the fruit and vegetable production systems in this region using a "cradle-to-gate" life cycle assessment. We provide standard measurable values of resource depletion; acidification and eutrophication hazards; global warming potential; and use of water resources. Once the crops and agricultural stages in critical need of intervention are identified, we propose and evaluate mitigation strategies to curb their impact. Our results show that in general woody crops have bigger footprints than vegetable crops, as they usually demand higher amounts of energy, pesticides, fertilisers and water, for considerably lower yields. Nonetheless, a turnabout in the carbon footprint was observed when CO2 fixation, which is commonly not included in Life Cycle Assessments (LCAs), was accounted for. This is due to the fact that woody crops, despite having higher emissions, are more efficient carbon sinks. When analysing impacts per agricultural stage, our results add more weight to the growing body of LCA-based evidence that irrigation, field work operations and fertiliser production have the most detrimental impacts. The most promising impact-mitigation action was the replacement of mineral fertiliser with manure, which offered potential footprint reductions of up to 10% and 21% for vegetable and woody crops, respectively. For woody crops, moderate impact reductions (up to 6% without a decline in yield) can also be achieved with deficit irrigation, which can be applied in synergy with mulching or organic fertilising. Finally, we compared our results against previous studies and highlighted comparability limitations, such as the inter-annual productivity fluctuations and the wide variability in agricultural practices.