COVERING PLASTIC FILMS FOR VINEYARD PROTECTED CULTIVATION
Plastic films used to cover vineyard change microclimate conditions aiming to advance or delay grape maturity according with the marked demand. The capacity of the covering materials to modify the greenhouse microclimate depends strongly on their radiometric properties. The films used to advance grape ripening must meet the following requirements: high transmissivity to solar radiation to increase the internal air temperature; high transmissivity in the Photosynthetically Active Radiation wave-length range to increase potential photosynthesis; low transmissivity in the long wave infrared radiation range to increase air temperature by reducing the thermal radiative losses; high transmissivity in the ultra violet ranges in order to promote fruit quality (colour and nutraceutic compounds). The aim of this paper is to study the radiometric characteristics of plastic films suitable for early harvesting in vineyard protected cultivation in European Mediterranean area. Several films, based on ethylene-vinyl acetate copolymer (EVA) and low density polyethylene (LDPE), were manufactured adding different light stabilizer systems. Laboratory tests were carried out on the films in order to evaluate their radiometric properties. The effect of the radiometric properties on ecophysiological leaf functioning (rates of stomatal conduc-tance, transpiration and leaf net photosynthesis) was evaluated under the covering in the vineyard. The results highlighted that the LDPE based film, containing an experi-mental additive aimed at shielding the near infrared component of the solar radiation, induced good ecophysiological results by allowing the passage of a high fraction of photosynthetically active radiation.
Vox, G., Schettini , E., Scarascia Mugnozza, G., Tarricone, L. and de Palma, L. (2014). COVERING PLASTIC FILMS FOR VINEYARD PROTECTED CULTIVATION. Acta Hortic. 1037, 897-904
radiometric properties, transmissivity, PAR, LWIR, table grapes