Crop management in semi-closed greenhouses

    Research output: Contribution to conferenceAbstractAcademic


    Closed and semi-closed closed greenhouses have been introduced as an innovation to reduce the energy consumption and improve crop yield. Savings of up to 30% in fossil fuel and production increases of up to 20% have been suggested. Economic feasibility of this greenhouse concept highly depends on the yield increase that can be obtained. Basis of the concept of closed greenhouses is that the greenhouse is a solar collector. The heat surplus in summer is harvested, stored and reused in winter to heat the greenhouse. The technical concept consists of a heat pump, underground seasonal energy storage (aquifer) as well as daytime storage, air treatment units for cooling, heating and dehumidification of air and air distribution systems. Ventilation windows are kept closed (closed greenhouse) or are sparsely opened (semi-closed greenhouse) enabling high CO2 concentrations throughout the whole year. These greenhouses allow a more accurate control of the climate factors (temperature, CO2 concentration and air humidity). It opens possibilities for combinations of climate factors that are not possible in conventional greenhouses. Typical characteristics of the growth conditions in semi-closed greenhouses are: high CO2 concentration, high humidity and controlled temperature under sunny conditions, less fluctuations in climate conditions, forced air movement, vertical temperature gradients (depending on place of inlet of conditioned air), changed difference between leaf and air temperature. This paper discusses the climate in closed and semi-closed greenhouses and its effects on yield. The effects on yield will be explained in terms of its underlying physiological and morphological processes, such as photosynthesis, stomatal opening, transpiration, assimilate partitioning and leaf area formation. To fully exploit the potential of semi-closed greenhouses we need to optimize not only one growth factor but all growth factors in relation to each other. Optimization includes not only the climate factors
    Original languageEnglish
    Publication statusPublished - 2009
    EventGreenSys 2009 - Quebec, Canada
    Duration: 14 Jun 200919 Jun 2009


    ConferenceGreenSys 2009


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