Identification of the main factors affecting the environmental impact of passive greenhouses

The objective of this study was to quantitatively evaluate the environmental impact of tomato production in passive greenhouses and to identify the most relevant environmental issues. The LCA approach was used in this study. A tomato crop was cultivated in a steel-framed greenhouse; plants were grown in a closed-loop irrigation system in which the substrate was perlite bags. With the exception of the toxicity indicators, the main sources of environmental impact were fertilizer production and the process for manufacturing the materials used for the greenhouse structure and the auxiliary equipment, substrate, irrigation and recirculation equipment. The relatively short life span of plastic covered greenhouse structures and the minimal input of external energy involved in the production process are the most important factors related with the production process. The study compared the use of two cladding materials: rigid PC sheet with a lifespan of 10 years and flexible LDPE film with a life of three years. The types of cladding compared in this study (PC sheet and LDPE film) are not particularly relevant for environmental analysis.