Film biodegradabili: aumenta il loro impiego nelle colture protette

The main results of three years of experimental field and laboratory trials using biodegradable films in agriculture are described. Trials were carried out in order to test innovative biodegradable materials for the protected cultivation of strawberry, of melon and tomato applying the cropping methods used in Southern Italy, and for open field soil solarization. Biodegradable films with different thickness were used for the soil mulching and for the covering of the low tunnels and they were compared with non biodegradable PE films. Climatic data of the site, air temperature and relative humidity inside the low tunnels and soil temperature under the mulching films were gathered during the tests. Besides laboratory radiometric tests, by means of spectrophotometers, were executed on the films in order to evaluate parameters such as the transmissivity in different wavelength ranges. All the films showed a low value for the long wave infrared transmissivity coefficient, changing between 3% and 31%, that induces the greenhouse effect inside the protected volume. The biodegradable transparent films showed high transmissivity coefficients in the solar range, values between 81% and 88%. The radiometric properties of the biodegradable films induce internal low tunnel air and soil temperatures equal or higher in comparison with the temperatures obtained using PE plastics. Concerning the agronomical productions, as marketable total yield and earliness, optimum results were obtained using biodegradable films. The experimental trials highlighted how the biodegradable films had the functionality needed for agricultural applications, such as the duration and the mechanical strength, during the whole experimental crop cycle. At the end of the cultivation period, biodegradable mulching films were shattered and buried with plants; ecotoxicity tests showed no evidence of ecotoxicity in the soil. The research showed that the biodegradable materials could be a sustainable alternative to the plastic films based on fossil raw materials