Mechanical properties decay and morphological behaviour of biodegradable films for agricultural mulching in real scale experiment Giacomo Scarascia-Mugnozza a , Evelia Schettini a , Giuliano Vox a , Mario Malinconico b, * , Barbara Immirzi b , Stefania Pagliara b a Department of Engineering and Management of the Agricultural, Livestock and Forest Systems (PROGESA), University of Bari, Via Amendola 165/a, 70126 Bari, Italy b Institute of Chemistry and Technology of Polymers, CNR, Via Campi Flegrei, 34 e Comprensorio Olivetti, 80078 Pozzuoli (Napoli), Italy Received 17 October 2005; received in revised form 20 January 2006; accepted 10 February 2006 Available online 21 June 2006 Abstract The use of plastic materials in agriculture causes the serious drawback of huge quantities of waste. The introduction of biodegradable ma- terials, which can be disposed directly into the soil, can be one possible solution to this problem. Biodegradable materials are actually innovative materials; therefore, their physical properties must be evaluated in relation to their functionality during the use in field. In the present research results of experimental tests carried out on biodegradable films used in strawberries protected cultivation are presented. The decay of some rel- evant physical parameters of biodegradable films during the cultivation period was monitored by laboratory tests (SEM analysis, mechanical tensile tests and infrared reflectance spectroscopy). Infrared spectroscopy clearly indicated that the mechanical degradation starts from the starch component of the material. Tensile tests showed that the value of elongation at break of biodegradable materials decreased in some cases by 300% after 10 days of field application. Ó 2006 Published by Elsevier Ltd. Keywords: Biodegradable material; Agriculture; Mulching film; Physical properties; Degradation; Solar radiation 1. Introduction The world consumption of plastic materials in agriculture amounts yearly to 6.5 million tons; more than 10% of the total consumption refers to plastic films for soil mulching [1]. The use of plastic films for soil mulching mainly for horticultural cultivation reduces the growth of the weeds, irrigation water consumption, the washout of nutrients into the ground water, the development of the plant diseases coming from the soil and the use of pesticides. Therefore, soil mulching contributes to a more sustainable agricultural production. Unfortunately the lifetime of plastic mulching films is re- duced owing to their prolonged exposure to climatic agents such as solar radiation, rain, hail, wind, high air temperature, high air relative humidity and by chemical products used dur- ing the crop cycle. As a consequence, due also to the necessity of soil tilling for agricultural needs, plastic mulching films can be used only for one or two cultivation periods, then they must be disposed off. Therefore, there is a huge consumption of oil- based material; moreover the recycling of mulching films is expensive and time-consuming due to the high labour cost for the collection, caused also by the direct contact of mulching film with the soil. Sometimes used plastic films are left on the field or burnt uncontrollably by the farmers producing the release of harmful substances with the associated obviously negative consequences to the environment [2]. A solution to this problem can be the introduction in agriculture of films pro- duced with biodegradable raw materials such as starch [3e6]; biodegradable films can be disposed directly into the soil or into a composting system at the end of their lifetime [7,8]. * Corresponding author. Tel.: þ39 081 8675212; fax: þ39 081 8675230. E-mail address: mali@ictp.cnr.it (M. Malinconico). 0141-3910/$ - see front matter Ó 2006 Published by Elsevier Ltd. doi:10.1016/j.polymdegradstab.2006.02.017 Polymer Degradation and Stability 91 (2006) 2801e2808 www.elsevier.com/locate/polydegstab