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Torrellas M.,IRTA Carretera de Cabrils | Anton A.,IRTA Carretera de Cabrils | Montero J.I.,IRTA Carretera de Cabrils | Baeza E.J.,Estacion Experimental de la Fundacion | And 2 more authors.
Acta Horticulturae | Year: 2012

The objective of this study was to identify the main bottlenecks of tomato production in a multispan tunnel greenhouse in a Mediterranean climate. This study was carried out as part of the EUPHOROS project, which aims to develop sustainable greenhouse production systems with a reduction of external inputs yet with high productivity. Life Cycle Assessment (LCA) was the methodology used to evaluate the environmental impacts of the production system. The system boundary was defined from raw materials extraction to farm gate, including materials waste disposal. The production system was modelled considering the following stages: structure, auxiliary equipment, climate control system, fertilizers, pesticides and waste. Results from the environmental assessment indicate that the burdens are the structure, auxiliary equipment and fertilizers. The structure was a major burden due to the large amount of steel in the frame. The high contribution of the auxiliary equipment was due to the substrate (perlite) manufacture and electricity consumption by the irrigation system. Fertilizers use had major environmental impacts as a result of both manufacturing processes and emissions because of their use. The main recommendations are oriented to reducing these impacts. Extension of greenhouse life span and increase in productivity could directly mitigate burdens per unit of produce, and recycling used substrate and reducing substrate volume per plant are both proposed. Since this soilless system was an open system, an efficient balance of both fertilizers and water is suggested. Source

Gazqueza J.C.,Estacion Experimental de la Fundacion | Lopez J.C.,Estacion Experimental de la Fundacion | Perez-Parra J.J.,Estacion Experimental de la Fundacion | Baeza E.J.,Estacion Experimental de la Fundacion | And 2 more authors.
Acta Horticulturae | Year: 2012

Control of the greenhouse microclimate during the summer is an important challenge in warm climate areas. Different cooling systems allow the limitation of high temperatures and/or low relative humidity levels inside the greenhouse. In the present work the microclimate conditions in three greenhouses with the same pepper crop and three different cooling systems were determined: T1 with mechanical ventilation; T2 fog system and natural ventilation and T3 plastic whitening with natural ventilation. The largest differences, between the systems, were found in the first weeks after transplanting, when plants had a low leaf area index (LAI<1) and high temperatures occurred outside the greenhouse. The maximum temperature differences (weekly average of maximum temperatures) between inside and outside the greenhouses, were 8.4°C for T1, 4.1°C for T2 and 5.1°C for T3. The maximum vapour pressure deficit values inside the greenhouses were 4.1 kPa for T1, 3 kPa for T2 and 3.7 kPa for T3. To maintain the assigned climate settings, the fog system consumed 138 L m-2 of water and the electricity consumption of the forced ventilation system was 9.3 kWh m-2 (growing cycle from 21 st July 2004 until 6th March 2005). As the final yields were very similar in the three treatments (no significant differences were found), we can consider that whitening of the plastic cover as the most efficient cooling system in terms of water and energy use. Source

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