Radiometric Properties of Plastic Films for Vineyard Covering and Their Influence on Vine Physiology and Production

Vineyard can be covered with plastic materials in order to protect vines and grapes from adverse weather conditions and to influence the microclimate, aiming at modifying the growing conditions in comparison with those in open field. This technique may advance berry ripening in table grapes. The radiometric properties of the plastic covering films influence canopy microclimate, leaf functioning, yield components and berry quality of grapevines. Three polyethylene films were tested in southern Italy in 2011: two commercial films, coded “YELLOW” and “NEUTRAL” according to their colour, and an experimental film coded “BASF”, as it was provided by BASF Italia Srl. The plastic films were tested on a seedless grapevine cultivar (Vitis vinifera ‘Sublima’) grown with a deficit-irrigation. The radiometric tests were carried out in laboratory. In the field, environmental parameters, such as photosynthetic photon flux, air temperature and relative humidity, were recorded. Moreover, the main parameters of vine ecophysiological activity, such as leaf gas exchange and vine water status, were investigated. At harvest, the vine productivity and the grape quality were assessed. The BASF and the YELLOW films were characterised by the PAR total transmissivity coefficient equal to 86.3 and 86.0%, respectively; the same coefficient was lower for the NEUTRAL film (81.8%). The YELLOW film was characterised by the highest solar IR transmissivity coefficient (90.0%), while the BASF film by the lowest one (81.0%). By analyzing the yield components, berry and cluster weight were found higher under the BASF film than under the other two types of covering films.