Assessment of the greenhouse gas emissions from aeroponic lettuce cultivation in Greece

Abstract

Soilless agricultural techniques such as aeroponics are considered innovative agricultural strategies that can help to mitigate global warming. The aim of the present study was to evaluate the greenhouse gas emissions from aeroponic lettuce cultivation in an automatic greenhouse in Greece utilizing the life cycle assessment methodology. Three aeroponic cultivations of lettuce were grown at different times of the year. The field inventory data collected during cultivation included the consumption of water, nutrients, and energy in the form of electricity. The results indicated that the greenhouse gas emissions ranged between 2.17 and 3.55 kg CO2 eq. per kg of lettuce produced. The cultivation performed during winter required more materials and energy for growth than the other cultivations and had the highest carbon footprint (3.55 kg CO2 eq. per kg of lettuce produced). Compared with the results from studies of lettuce cultivation in soil, the CO2 eq. emissions per kg of lettuce in the present work were higher. However, the emissions generated by aeroponic cultivation were comparable to or even lower than those from cultivation methods that require the recirculation of water and/or nutrients using equipment that runs on electricity. It seems that energy is the price that society has to pay if soil is to be replaced as a key natural resource for the production of food.