Chapter 3: An Overview on Innovative Biodegradable Materials for Agricultural Applications

The world consumption of plastic materials in agriculture amounts yearly to 6.5 million tons, among which more then 10 % refers to plastic films for soil mulching. The use of plastic materials causes the serious drawback of huge quantities of waste to be disposed off and in the last decades the growing environmental awareness has been prompting the development of a new generation of materials created starting with raw materials from renewable origin. These materials have to retain their physical and mechanical properties while in use and have to be biodegradable or compostable at the end of their life, degrading via micro-organisms into carbon dioxide or methane, water and biomass. Within the EU Projects “BIOPLASTICS” and “BIO.CO.AGRI”, several biodegradable materials for soil mulching were prepared using natural polymers, such as starch, cellulose, chitosan, alginate and glucomannan, as pre-competitive research products. These innovative materials were obtained by thermal film forming processes, casting and spraying techniques. Real scale field cultivation tests were carried out from 2001 to 2005 in order to study the relevant physical and mechanical properties, the degradation process, the morphological behaviour and the performance in the field of these materials in comparison to commercial oil based non renewable raw materials. In this paper a focused overview on the formulation development, processing understanding, field performance and mechanical and radiometric properties of these innovative materials for mulching agricultural application is presented in comparison to oil based non renewable materials. The radiometric properties and their effect on the temperature condition and on weed control in the mulched soil were evaluated. The biodegradable materials could be the environmentally friendly alternatives to synthetic petro-chemical polymers and could contribute to a sustainable agriculture.