Biodegradable Spray Mulching Coatings Based on Hydrolyzed Protein

The use of mulching films made from non-renewable fossil fuels causes the serious drawback of huge quantities of plastic wastes to be disposed of. Over the last years the growing environmental awareness has prompted researchers to develop a new generation of mulching products starting with raw materials from renewable origin. These materials have to retain their physical and mechanical properties while in use, to be compostable or digestible anaerobically at the end of their life, and to be degradable via micro-organisms into carbon dioxide or methane, water and biomass when integrated directly in the soil. Aim of the research was the development of biodegradable polymeric materials based on hydrolyzed proteins, derived from waste products of the leather industry. Particular attention has been devoted to evaluate the application of such biobased materials in the agricultural practice of mulching. Biobased mulching films were generated in situ by low-pressure spraying of polymeric water dispersion on the soil; the mulches were tested in a Romaine Lettuce Mortarella cultivation inside a greenhouse from November 2013 to January 2014. This paper describes the functionalities of the new bio-based mulching coatings, which were developed and tested in a real scale field cultivation test. During the test in the field, the biodegradable soil mulching materials showed suitable properties for an efficient and profitable use in agriculture. The innovative biodegradable spray coatings lasted in the field up to 2 months. Tests on the lettuce yield and on the properties of the soil under the mulching coatings were carried out. The biodegradable materials could be the environmentally friendly alternatives to synthetic petro-chemical polymers and could contribute to a sustainable agriculture.