ISHS Acta Horticulturae 170: Greenhouse Construction and Covering Materials
INFLUENCE OF DIFFERENT STATIC AERATION SYSTEMS ON THE DIURNAL CLIMATE UNDER PE GREENHOUSE |
| Authors: | H. Verlodt, S. Baeten, S. El Fahem, Y. Harbaoui |
| Abstract:
Air temperature at two levels, soil temperature, relative humidity and enthalpy of the air under five plastic greenhouses from the hemispheric type (30 m of length and 8 m of width) and equiped with different aeration systems, were compared to the outdoor and this in function of wind velocity and direction, outdoor temperature and global solar radiation. The first greenhouse was covered with a perforated PE film of 100μm of thickness and with 500 holes/m2. The second and the third greenhouses were covered by alternating longlife PE sheets of 180μm and 6 m of width with annual PE sheets of 100μm and 2 m of width. In the first case the annual PE sheets were consisted in 3 removable sheets - one at each lateral sides and one on the ridge -. This individual sheets were fixed at the crossbars. In the second case the movable sheets were moved from both edges to the center by a hand winch and this in the middle of the ridge and at both sides at 1.5 m of height. The fourth greenhouse has a mecanized aeration by pushing away the PE sheets in the ridge with a lateral aeration by perforation of the PE sheets near the ground surface by means of 3 holes of 40 cm of diameter each 2.25 m. During the winter period the aeration holes are covered with a supplementary PE sheet of 80 cm of width, which was flash sealed on the original PE sheet. The fifth greenhouse was a control greenhouse with lateral aeration only by pushing away manually the 6 m width PE sheets with 35 cm long wooden peg. The greenhouses were cultivated with a muskmelon crop and results on plant development, fruitset and production are discussed in relation to the climatological results. | |
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