Environmentally friendly development of Norwegian greenhouse industry (VEKSTHUS) (194861)

The political agenda nationally and internationally is focused on expected climate change and how to reduce CO2 emission from burning fossil fuels. The energy consumption in the greenhouse industry is high, and there is a strong political pressure to redu ce it. In the Netherlands, so-called semi-closed or closed greenhouses are under development, and they have the potential to substantially increase yield and reduce energy consumption. However, effects of climate control on plant growth in such greenhouse s are limited. Our goal is to contribute to this lack of knowledge and thereby to a more energy efficient greenhouse production. Our research task is to maximize the utilization of natural radiation and thus reduce energy consumption by allowing larger te mperature variation in order to reduce ventilation. A higher CO2 concentration will be maintained inside the greenhouses to be utilized by the plants, and CO2 emission will be reduced. There may be negative effects on plant quality by shoot elongation (hi gh day and low night temperatures), but this will be counteracted by altering light quality by means of different greenhouse covering and shading materials as well as light emitting diodes (LED light). From recent experiments in Norway, we know that light duration and light quality also strongly affects development of powdery mildew in roses, and by means of low-energy LED lamps we intend to explore the possibilities of developing similar control measures in cucumber and tomato. Biological control of pest insects and mites is common in Norwegian greenhouse industry, especially in vegetables, and consequences of changes in greenhouse climate on biological pest control will be investigated. The model crops in the project will primarily be roses, cucumber, t omato and poinsettia, and we will cooperate with scientists in The Netherlands, Canada, USA and Finland.