|Riassunto in Inglese:|
A research on four double-span greenhouses with different roof opening systems, with natural or forced ventilation, in the presence of a cultivation of Gypsophila paniculata L., was conducted with the aim to evaluate the influence of vent typology on internal climate and on flower crop response. A one-year trial was carried out in Bagheria (Sicily, Italy), in unheated environments with metal structure and PE cover, differing for roof vents and for presence, number and location of ventilators. Cultivars ‘Dana’, ‘Paniculata’ and ‘Perfecta’ were tested and grown in soilless culture. Data on internal climate were collected by a system of thermo-hygrometric sensors connected to a data logger, analysed with a platform software and compared to the external values. Roof vent typology affected greenhouse air temperature and relative humidity (RH) as well as crop yield and quality. During summer, the maximum values of air temperature (38.7°C) and the minimum values of RH (31.2%) were measured in the greenhouse with chimney top vents. In the same period, the lowest temperature increases (+7.2°C) and hygrometric reductions (-12.5%) were recorded in the structure equipped with seagull-wing vents and two head-ventilators. In the latter greenhouse, highest productive (78 flower stems m-2) and qualitative (1027 g m-2) results were achieved. Significant differences were evidenced among cultivars: ‘Paniculata’ produced the maximum amount (103 flower m-2) of stems, ‘Dana’ supplied those with the highest average weight (1705 g m-2).