THE INFLUENCE OF P.V.C. TUNNELS AND VENTILATION ON STRAWBERRY CULTURE
With reference to these three aspects the application of plastic protection in strawberry culture gives the possibility of bettering the technical and economic sides.
In the special case of tunnels, one of the most important aspects concerns the ventilation technique. There are two ventilating tendencies, one using complex or simple mechanisms which are easily handled, and the other using perforated sheets, giving remarkable practical advantages which compensate for the reduction in earliness (Lemaire 1964, D'Ogny e Vesco 1965, Brun e Gineaux 1966, Brun 1968, Tesi 1968).
In cold climates perforated tunnels do not seem advisable (Brun 1968) because of the scarce thermal efficiency, especially if they are small. In our climate (Mediterranean Basin) where frosts have an average annual frequency smaller than 10 days, we think that perforated tunnels of small sizes, 50–60 cm high, represent a rational solution.
n our experiments we have used tunnels with different perforated surfaces that were compared with the traditional opening of the tunnels. Our results apply to flowering and yield of strawberry culture in the first two years after planting.