The present work was carried out with the objective to evaluate the micrometeorological conditions inside low tunnels cultivated with lettuce. A technique used to improve the ventilation inside the tunnels is the perforation of the plastic film, though still not very well known. Therefore, tunnels were tested without and with lettuce crop, with 0, 5, 10, 15 and 20% of perforated film area and in soil without tunnel, during spring. The meteorological variables used for the evaluation of the treatments were temperature and relative humidity of air. It was verified that the elevation of the temperature inside the protected atmosphere was inversely related to percentage of perforation contrary to the humidity loss for the external atmosphere. The production obtained under protected conditions was higher and of better quality.
Lactuca sativa L.; low tunnel; plasticulture; microclimate
