Physical Properties of Innovative Spray Biodegradable Coatings for Soil Mulching in Greenhouse Cultivation

In order to overcome the serious drawback of huge quantities of plastic waste obtained at the end of the life of agricultural plastic mulching films, researches on innovative biodegradable materials have been developing. The paper examines a new sustainable approach in which a water solution of natural biodegradable polymers is sprayed on a cultivation area in order to form a mulch coating. The material used is a blend of two polysaccharides, such as Guar Gum and Locust Bean Gum additivated with glycerol. A protected field experiment was conducted to test the effectiveness of spray black biodegradable mulching coating in a tomato crop in Southern Italy. Field performance and physical properties, evaluated by means of laboratory tests, are compared to those of commercial low density polyethylene and biodegradable starch based mulch films. The spray mulching coating is opaque in the solar radiation range and behaved as a black body. The tested spray coating showed much lower values of tensile stress and elongation at break in comparison with the values of commercial low density polyethylene and biodegradable starch based mulch films. Such innovative coatings were characterised by functionality during their use in field. Results indicate that the biodegradable spray coatings could be a sustainable alternatives to plastic films based on fossil raw materials.