ABSTRACT

Low-density polyethylene homopolymer (PE-LD) and ethylene-vinyl acetate copolymers (EVA) are the most common plastics materials used for greenhouse cover films. There is only one major exception. In Japan, plasticized poly(vinyl chloride) (PVC) is used to a large extent. The growing importance of plastics films for greenhouse covers is best illustrated by a few figures. In 1976 the surface covered with greenhouse films worldwide was approximately 60,000 ha (1). In 1980 the corresponding surface surpassed 80,000 ha (1) and reached 220,000 ha in the 1990s (2). The impressive development of the use of greenhouses is best visualized with a country from southern Europe, such as Spain. In fact, Spain went through a tremendous evolution for the agricultural surface covered with greenhouses: from 343 ha in 1967, to 5,800 ha in 1976, to 15,000 ha in 1983 (3), and an area of 28,000 ha in the 1990s (2). Although there is some leveling off in the total area covered with greenhouses in southern Europe, the development is likely to continue in other parts of the world, in particular in South America (4).