Comparing the Environmental Impacts of Greenhouse versus Open-Field Tomato Production in the Mediterranean Region

Greenhouse production is often perceived as an artificial process, characterized by low nutritional quality of the final product and the heavy use of chemical inputs. Moreover, large areas covered with greenhouses create a big visual impact, a factor which is especially important in the highly touristic Mediterranean Coastal. In contrast, open-field cultivation is generally perceived as an 'eco-friendly' activity, and one that has a much smaller visual impact. Setting aside these,apparent' perceptions of the two cultivation systems, it is necessary to make an objective assessment and to quantify their respective impacts on the environment. Life cycle assessment (LCA) tool was used to compare the environmental burdens associated with greenhouse as opposed to open-field production processes for a spring season tomato crop grown in the Maresme region near Barcelona. Greenhouse structure, irrigation equipment, fertilizers, pesticides, cultural tasks and irrigation were all analyzed as subsystems. All inputs for each subsystem were traced back to primary resources. For each subsystem, emissions were quantified and aggregated into impact categories defined by CML 2001, using tomato yield (kg) as the functional unit. Preliminary results revealed that environmental burden per kg of tomato grown in open-field production was greater than that for tomatoes produced in greenhouses with respect to factors such as the use of water, fertilizers and pesticides. Notwithstanding the differences in environmental burden associated with the two production systems, if one considers the higher economic returns obtained from greenhouse production, their existence could constitute a reasonable trade-off.