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Issue 02/2017

  • Text
  • Bioplastics
  • Packaging
  • Biodegradable
  • Materials
  • Products
  • Biobased
  • Films
  • Plastics
  • Compostable
  • Germany


Agriculture/Horticulture Biodegradable mulch films: where are we? Biodegradable mulch films have been commercially available since the beginning of the 2000s. Throughout the years, various projects (e.g. EU projects, such as Bioplastics 2001-2005 and Agrobiofilm 2011-2013) have focused on their development; they have also been the subject of many publications. Also, these films are now used by many growers (see INFO BOX 1) in order to improve the yield and quality of the crops. Biodegradable mulch films have gained a place and a role in the world of agricultural plastic (see INFO BOX 2), especially in the last decade; in fact, roughly 5 % of the mulch film sold in Europe today (80,000 tonnes/year) is biodegradable. The films are largely used in Italy, France, Germany, Benelux and Spain, mainly for vegetable crops. It has been estimated that almost half of the plastics worldwide are used for disposable applications [2]. A mulch film may be considered disposable due to its relatively brief service life (between 4 and 10 months), after which, at the end of the cultivation period, it needs to be removed from the field and disposed of, according to provisions of the European directives dealing with waste management (directives 99/31 EC, 2000/76 EC, directive 2008/98/EC). In Spain and Italy, no more than 50 % of this used agricultural plastic is recovered, of which some 50 % goes to landfill [3]. Recovered mulch film is generally heavily contaminated with soil, stones and biological waste (up to 60-80 % of its initial weight), which makes mechanical recycling difficult [4]. Mulch films that are not properly be collected tend simply to be left in the environment (dumped or buried in the soil) or burned on the fields, which negatively impacts the environment [5]. Biodegradability, as a property, raises interesting possibilities for an efficient solution to tackle a series of problems connected to waste management. Biodegradable mulch films do not need to be removed from the soil, as they are able to be biodegraded by soil microorganisms (mineralization). The use of biodegradable mulch films eliminates altogether the costs of collection and disposal of very dirty and non-profitable materials and it is fully in line with the EU Strategy on Waste Management (1989). Biodegradable mulch films that can be left in the soil after use must meet the biodegradability and non-ecotoxicity requirements applicable for this environment. The current available standards for biodegradable mulch films in Europe are the French NF U 52 001:2005 and the Italian UNI 11495:2013 standards. The CEN TC 249/WG 7 Committee is preparing a European Standard on biodegradable mulch films. This will be a useful tool to provide a shared foundation for the definitions and requirements for these products. In general, to qualify as biodegradable according to existing norms and standards, a biodegradable mulch film should provide a minimum biodegradation threshold of 90 % (relative to a standard material) in two years and an ecotoxicology assessment in soil is required (see INFO BOX 3). The OK Biodegradable Soil program developed by the Belgium certification body Vinçotte is the main reference in the European market to clearly identify a biodegradable mulch film. Nonetheless, some oxo— degradable or photo-degradable mulch films can be found on the market, and are used by growers. These films claim to be biodegradable but do not meet requirements of the available standards. They are produced from traditional polymers formulated with specific additives which improve the physical degradation (fragmentation) of the films. The films break down into small pieces and fragments, which then persist in the environment. Appropriate communication measures are still needed in order to ensure that farmers and other stakeholders are informed of and understand these differences. Substantial evidence has been gathered over the past 15 years showing that biodegradable mulches on vegetable crops behave in the same way functionally as conventional nonbiodegradable films, from an agronomic and mechanical point of view. The use of biodegradable mulches can be also introduced in crops in which, for various reasons, mulch films have tended not to be applied. The biodegradability of the materials becomes a useful agronomical feature in all cases where traditional mulch films cannot be properly collected from the field (perennial crops) or the presence of a mulch film would make specific agronomical operations difficult (processing tomatoes), or if efficient weed control is difficult to achieve with traditional strategies in low input techniques (rice). In some areas of Europe, vineyards are mulched with films in the first year of cultivation. This improves the development of the plant (successful and homogeneous growth) and offers an option for weed control on the row. In Southern France, biodegradable mulches were shown to be a good alternative to non-biodegradable ones, in terms of positive effects on plant growth and on yields (after harvesting at 18 months). On analyzing the root systems of the mulched and the unmulched vines, the biodegradable mulches were found to provide improved root system growth [6]. The two most important European areas for processing tomatoes (Spain and Italy) have introduced the use of biodegradable mulches in tomato production. This technique can reduce the use of herbicides in weed control, improve root development, offer protection against low temperatures at the beginning of the crop cycle and, finally, produce higher yields [7]. Rice is another crop that benefits from the use of biodegradable mulches. In the last two years, the use of biodegradable mulches in one of the main European rice cultivating areas (North West Italy) has demonstrated that biodegradable mulch films can control weeds and enhance rice growth, drastically reducing the use of herbicides [8]. The use of biodegradable polymers in well-defined application areas is definitely an interesting possibility for the 22 bioplastics MAGAZINE [02/17] Vol. 12

Agriculture/Horticulture By: Sara Guerrini Public Affairs Agriculture Sector Novamont Novara, Italy agricultural sector. For this sector, they offer a very real opportunity to reduce the level of chemical inputs in the cultivated crops. [1] APE Europe, European non packaging agriplastics market survey, 2013;; [2] J. Hopewell, R. Dvorak, E. Kosior, 2009, Plastics recycling: challenges and opportunities. Philos Trans R Soc London [Biol] 364:2115–2126; [3] European project LabelAgriWaste: rcn/75804_en.html; [4] Sorema, 2008, Recycling schemes for thin mulching agricultural film. Analysis of the process and applications examples, International Congress Plastic and Agriculture. MACPLAS 2008, Bari, Italy, 21-22 February 2008. [5] J.W. Garthe, B.G. Miller, 2006, Burning High-Grade, Clean Fuel Made; [6] F. Touchaleaume et al., 2016, Performance and environmental impact of biodegradable polymers as agricultural mulching films, Chemosphere, 144: 433-439; [7] CIO (Consorzio Interregionale Ortofrutticoli), 2016, Risultati Sperimentazione 2016; [8] Novamont’s communication, 2016. INFO BOX 1 – agronomical advantages of mulch films Mulch films are generally used for: • Increasing yield and improving quality of crops; • Controlling weeds (black or pigmented mulches); • Reducing use of irrigation water (up to 30 %, compared to bare soil) and pesticides; • Enhancing early crop production (mainly clear films); • Increasing the temperature and moisture in the soil. Biodegradable mulches have shown the same positive effect as non-biodegradable mulch films. INFO BOX 2 - some numbers of plastics for the agriculture sector The global consumption of plastic films in agriculture amounted to about 4 million tonnes in the year 2013; the biggest user was Asia (roughly 70 %), followed by Europe (16 %). Of the 510,000 tonnes of agricultural films used in Europe, some 40 % is accounted for by the countries of southern Europe, where these films are used for horticultural purposes (greenhouse covers and mulching); the annual consumption of mulch film in Europe is 80,000 tonnes; 5 % of the films used are biodegradable [1] INFO BOX 3 – BIODEGRADATION Biodegradation: degrading process caused by biological activity, especially enzyme action, which leads to a significant change in the material’s chemical structure. It is a complex process in which the carbon of a polymer is converted into carbon dioxide (mineralization) and biomass. The biodegradation test measures only one product of the reaction (in this case the carbon dioxide), the residual 10 % is considered to be assimilated in biomass. According to the scientific community, mineralization (i.e. conversion into carbon dioxide) of plastic material corresponding or exceeding 90 % means that complete biodegradation has been reached. bioplastics MAGAZINE [02/17] Vol. 12 23

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