Vertical temperature gradients in the semi-closed greenhouses: occurrence and effects

    Research output: Chapter in Book/Report/Conference proceedingConference paper

    9 Citations (Scopus)

    Abstract

    Semi-closed greenhouses have been developed in which window ventilation is minimized due to active cooling, enabling enhanced CO2 concentrations at high irradiance. Cooled and dehumidified air is blown into the greenhouse from below or above the canopy. Cooling below the canopy may induce vertical temperature gradients along the length of the plants. Our first aim was to analyze the effect of the positioning of the inlet of cooled and dehumidified air on the magnitudes of vertical temperature and VPD gradients in the semi-closed greenhouses. The second aim was to investigate the effects of vertical temperature gradients on assimilate production, partitioning, and fruit growth. Tomato crops were grown year-round in four semi-closed greenhouses with cooled and dehumidified air blown into the greenhouses from below or above the crop. Cooling below the canopy induced vertical temperature and VPD gradients. The temperature at the top of the canopy was over 5°C higher than at the bottom, when outside solar radiation was high (solar radiation >250 J cm-2 h-1). Total dry matter production was not affected by the location of the cooling (4.64 and 4.80 kg m-2 with cooling from above and from below, respectively). Percentage dry matter partitioning to the fruits was 74% in both treatments. Average over the whole growing season the fresh fruit weight of the harvested fruits was not affected by the location of cooling (118 vs 112 g fruit-1). However, during summer period the average fresh fruit weight of the harvested fruits in the greenhouse with cooling from below was higher than in the greenhouse with cooling from above (124 vs 115 g fruit-1)
    Original languageEnglish
    Title of host publicationISHS 28th Int. Horticultural Congress - Science and Horticulture for People (IHC 2010): International Symposium on Greenhouse 2010 and Soilless Cultivation
    EditorsN. Castilla, O. van Kooten, S. Sase, J.F. Meneses, W.H. Schnitzler, E. van Os
    Place of PublicationLisbon, Portugal
    PublisherISHS
    Pages59-66
    Volume927
    ISBN (Print)9789066057241
    DOIs
    Publication statusPublished - 2012
    Event28th International Horticultural Congress -
    Duration: 22 Aug 201027 Aug 2010

    Conference

    Conference28th International Horticultural Congress
    Period22/08/1027/08/10

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  • Cite this

    Qian, T., Dieleman, J. A., Elings, A., de Gelder, A., van Kooten, O., & Marcelis, L. F. M. (2012). Vertical temperature gradients in the semi-closed greenhouses: occurrence and effects. In N. Castilla, O. van Kooten, S. Sase, J. F. Meneses, W. H. Schnitzler, & E. van Os (Eds.), ISHS 28th Int. Horticultural Congress - Science and Horticulture for People (IHC 2010): International Symposium on Greenhouse 2010 and Soilless Cultivation (Vol. 927, pp. 59-66). Lisbon, Portugal: ISHS. https://doi.org/10.17660/ActaHortic.2012.927.5