Benefits of a semi-closed greenhouse for tomato production in the West of France

S. Le Quillec, B. Albert, D. Lesourd, D. Loda, R. Barette, E. Brajeul
The improvement of the energy use efficiency of the greenhouses while keeping a similar or better yield appears as a key factor for the French tomato producers. To answer this issue, the Ctifl centre located in Carquefou built 3 new compartments of 1037 m2 at the end of 2013, including a comparison between a control (with standard equipment and climate management) and a semi-closed glasshouse (the Ultra-Clima® concept by Kubo). The potential of that new system in the West of France, in terms of climate and microclimate, crop protection, plant behaviour, fruit yield and energy savings began to be characterized on an early soilless tomato crop in 2014. Among first overall results, the semi-closed section had a much more stable climate (air temperature and humidity) compared to the control, which was more under the influence of the outside air temperature and wind speed during ventilation. It was also possible to maintain a higher CO2 concentration inside without additional supply. The use of the air cooling by pad and fan system made the crop more vigorous during summer, by lowering both temperature and vapour pressure deficit easily. Controlled air-cooling system was useful too in order to manage the pre-night period. Furthermore, the ability to maintain the heating set points from low-temperature water (by heat pump, unavoidable energy, etc.) in the semi-closed greenhouse is very interesting with the aim of reducing energy consumption. Finally, a higher production (up to 5% more) from the first testing year is very promising for the near future. It is now necessary to optimize this breaking innovation in 2015 (about overpressure regulation, roof and sidewall ventilation, use of the various heating networks, fan speed, CO2 supply, etc.) to adjust it at best to the French western weather conditions.
Le Quillec, S., Albert, B., Lesourd, D., Loda, D., Barette, R. and Brajeul, E. 2017. Benefits of a semi-closed greenhouse for tomato production in the West of France. Acta Hort. (ISHS) 1170:883-888
Solanum lycopersicum, climate control, cooling, energy savings

Acta Horticulturae