Geoola, F., Inst. of Agric. Engineering ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Cakmak, B., Farm Machinery Dept. of Agric. Fac, Ege Univ., Bornova Izmir 35100, Turkey
Kashti, Y., Inst. of Agric. Engineering ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Ulusoy, E., Farm Machinery Dept. of Agric. Fac, Ege Univ., Bornova Izmir 35100, Turkey

In this research, optical and mechanical properties of three different types of (polyethylene) PE plastic films commonly used for cladding greenhouse in TURKEY were studied. The three types of plastic films were UV (Ultraviolet), UV-IR (Ultraviolet and Infrared) and UV-IR-AF (Ultraviolet, Infrared and Antifog). For this study, three different experimental greenhouses developed and constructed by Institute of Agricultural Engineering ARO, the Volcani Center were used. One of the experimental greenhouses was used to investigate the effect of agro-chemical (sulfur) on the mechanical properties of cladding materials. This greenhouse had 30 identical sections. Each film was fixed on a rectangular aluminium frame. The frames were mounted on these sections. The second greenhouse was used to investigate the solar radiation transmission characteristic of plastic films. The last one was used to investigate the ageing of cladding materials in general. The experiments on the effect of sulfur evaporation on plastic films were started in June 1997 for period of 3 months. The results with sulfur evaporation on mechanical properties of PE films indicated that the elongation that take place in PE films treated with sulfur reduced about 60-80 %.