ISHS Acta Horticulturae 801: International Symposium on High Technology for Greenhouse System Management: Greensys2007
EFFECTS OF A DYNAMIC LIQUID FOAM TECHNOLOGY ON ENERGY CONSUMPTION, MICROCLIMATE, LEAF GAS EXCHANGES AND FRUIT YIELD IN GREENHOUSE VEGETABLE PRODUCTION |
| Authors: | K. Aberkani, X. Hao, A. Papadopoulos, A. Gosselin, D. de Halleux, M. Dorais, S. Khosla, J. Villeneuve, L. April |
| Keywords: | Temperature, light, fruit firmness, russeting and fruit cracking, stress, photosynthesis |
| Abstract:
The climate in most greenhouse crop production areas in Canada is of a continental type, characterized with cold winters and hot summers. To produce greenhouse crops successfully, significant heating is required in the winter while considerable cooling/shading is needed in the summer to maintain suitable greenhouse microclimate. Sunarc of Canada had developed a new technology where liquid foam is injected into the space between the double layers of polyethylene films in D-poly greenhouses to enhance insulation in winter and for shading in summer. The effects of shading of liquid foam on greenhouse microclimate and productivity of tomatoes and sweet peppers were investigated in the summer of 2006. Control (no shading) and two shading strategies (Shade1 and Shade2) were tested; each was applied to one greenhouse. Shading by the foam and sprinkler systems was applied according to greenhouse air temperature and outside solar radiation. Greenhouse air temperature was reduced by 1.3°C when the sprinklers were used. With the use of liquid foam, the air, leaf (5th), stem and fruit temperatures of tomato plants were reduced by 3.9°C, 6.8°C, 5.1°C and 1.2 °C, respectively. Accordingly, leaf (5th), stem and fruit temperatures of sweet pepper plants were reduced by 2.5 °C, 2.1 °C, 2.1 °C, respectively. Fruit cracking incidence was reduced by the shading. We also conducted fall and winter trials to evaluate the energy-saving potential of this technology. Liquid foam reduced the heat loss through the greenhouse roof (insulated by the foam) by about 40 % to 50 % during the night. | |
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