ISHS Acta Horticulturae 287: II International Symposium on Protected Cultivation of Vegetables in Mild Winter Climates
THE INFLUENCE OF GREENHOUSES ON INTERNAL CLIMATE WITH SPECIAL REFERENCE TO MEDITERRANEAN REGIONS |
| Author: | Joe J. Hanan |
| Abstract:
The influence of outside climate on internal greenhouse environment is discussed with some examples from other regions as applied to the Mediterranean situation. Greenhouses must be adapted to this mild, semi-arid, high radiation region which offers relatively high efficiency in respect to input energy requirements. Secondly, the low windspeeds inherent to these structures mean that special effort should be given to supplying CO2 to the leaf surfaces even though the greenhouse may be fully ventilated. Existing structures now, on the average, transmit only about 60 % of outside solar radiation. Therefore, efforts should be made to enhance transmittance in order to avoid yield reduction in the mid-winters. The use of percent relative humidity should be discouraged, with humidity control based upon absolute vapor concentration and vapor pressure deficit (VPD). The Mediterranean climate offers the best opportunities for economic application of solar heating. | |
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