Agriculture/Horticulture
Agriculture/Horticulture Bioplastics in Agriculture and Horticulture By: Smith, D., Gaugler, M., Graichen, F. Scion Rotorua 3046, New Zealand Bioplastics for Agriculture/Horticulture in a sustainability context It is interesting to reflect on the challenges of plastics and bioplastics in agriculture and horticulture applications with the recent communications around the European Green Deal [1] in mind. There is broad agreement that, in addition to the principles set out in this roadmap, we will need a broader perspective, including connectivity to the bioeconomy. It is neccesary to link bioeconomy and circular economy. Without considering the organic/biological material cycles and the challenge of contaminated waste, a transition to a circular economy and Europe’s ambitious goals of becoming a resource-efficient and competitive economy with zero net greenhouse gas emissions by 2050 will hardly be possible. Bioplastics in the agriculture and horticulture sectors are a great example for the challenges and opportunities through the convergence of circular economy and bioeconomy. In 2019 Schuttelaar and Partners outlined the current use of plastics in agriculture [2]. Currently 2 % of plastics globally produced are used in agriculture applications. This ratio is expected to increase – especially given the rapid growth of the market for agricultural films. Considering the ongoing sustainability discussions around plastics, it is easy to forget that the use of plastics in both the agriculture and horticulture sectors has resulted in increased crop production, improved food quality, reduction of food waste as well as the improvement of the overall ecological footprint. For a world that is facing challenges like feeding 10 billion people by 2050, a plastic waste flood and reduced availability of finite resources – acceleration of innovative and sustainable solutions in both sectors is required. One major challenge of the use of plastics in both agriculture and horticulture sectors is the associated plastic waste and environmental impacts. While recycling and recovery are sometimes the appropriate solution – plastic and plastic products deployed in both sectors are dominated by short duration/single use. This requires specific end of life considerations as large amounts of waste plastics must be properly managed (burning, abandoning, burying or wild landfilling are unsustainable solutions). Additionally, it is necessary that the sources of the feedstock used for these plastic applications and the respective end of life options are closely interlinked. It is critical to make use of the bioeconomy/circular economy linkage and change the conversation to sustainable/renewable carbon as feedstock for the material used. Sustainable carbon can be derived from three sources – instead of using virgin fossil-based material (cf. bioplastics MAGAZINE 01/2020 [3]] (1) Technosphere (recycled plastics and composites) (2) Atmosphere (CO 2 -based plastics and materials) (3) Biosphere (biobased plastics and composites) These three sources should not be competing against each other – for different materials and regions one or the other solution might be preferred. One can even expect different feedstock sources for the same material, depending on seasonal or local feedstock availability, e.g. polyhydroxyalkanoates (PHAs) from carbon dioxide vs from biomass residue. A similar concept applies to the appropriate end of life options: (1) Reuse (2) Recycle (3) Biodegradation/composting It is not about which end of life option is superior – it is about appropriate solution for any given product in their specific environment. The following part outlines the global and New Zealand specific state of the art of bioplastics use in agricultural and horticultural products. Current example of plastics used in the Agriculture/Horticulture industry In both sectors – plastics are used for a wide variety of applications – Plastics Europe [4] and Scarascia-Mugnozza [5] outlined some of the best-known examples for materials and applications. A wide range of plastics are used in agriculture, including, polyethylene (PE), Polypropylene (PP), Ethylene-Vinyl Accetate Copolymer (EVA), Poly-vinyl chloride (PVC) and, less frequently, Polycarbonate (PC) and poly-methyl-methacrylate (PMMA). The most important applications include: • Greenhouses • Tunnels • Mulching/mulch film • Netting • Piping • Silage wraps, strings (twine), ropes and pots • Plastic reservoirs/irrigation systems • Packaging of agricultural products Biobased plastics & materials in agriculture/ Horticulture – International examples Looking at the requirements for plastics in the agriculture and horticulture sector reuse and recycle come with big 18 bioplastics MAGAZINE [02/20] Vol. 15
Agriculture/Horticulture Food for Thought Is it feasible to have a consistent standard for all agriculture and horticulture products, not just mulch? If the mulch standard is the only current standard for biodegradation in soil, what claims can manufacturers of biodegradable clips, sleeves and others make? challenges. The products get in contact with soil, dirt, plants and other materials – therefore mechanical recycling or reuse are not suitable in most cases. For these applications – degradability and/or compostability are largely the preferred end of life options. It is not surprising that bioplastics play an increasing role in these sectors – some of the best-known products today include plant pots and mulch films [6]. However, while biodegradable plastics may currently be seen as only differing in end of life option from nondegradable counter parts, they will enable wider system changes and open possibilities with significant additional environmental and economic benefits. Several companies – such as SelfEco [7] - are a good examples for innovations in this space –providing biobased and compostable plant pots that also deliver nutrients directly incorporated into the degradable pot walls. Delivering targeted nutrients at defined locations and growth stages of the plants reduces nutrient leakage, i.e. loss. Biodegradable mulch films are becoming more and more readily available [8, 9] – allowing food production with a minimum use of pesticide and reduced use of irrigation water. Ploughing-in of mulching films after use instead of collecting them from the field is practical and improves the economics of the operation. Biobased plastics & materials in agriculture/ Horticulture – New Zealand examples New Zealand is a country dominated by the primary sectors – such as agriculture, forestry and horticulture and has all the setting and ingredients for a successful circular bioeconomy. Scion has been applying a sustainable design approach combined with research and development of bioplastics for many years. Scion has developed several solutions to enable the transition to a circular bioeconomy. A number of these were developed with the agriculture and horticulture sector in mind [11] – examples include: • Net Clips • Spray Guards • Tree sleeves • Erosion control pegs • Supports What about standards and testing? A big challenge for both industry and consumers is the lack of consistent certification standards. While a standard (EN 17033) for agriculture/horticulture mulch film exists [10] – this is largely not applicable for most other products. To avoid mislabelling and greenwashing, a consistent standard must be developed and implemented. EN 17033 specifies not only regulated metals, biodegradation and ecotoxicity, it also specifies mechanical and optical properties of the films. If a product passes three out of the five criteria - chemical analysis, biodegradation (>90% in 2 years at ambient soil conditions in soil, not compost or vermiculite) and ecotoxicity, is this good enough? If so, what claims can be made? What about samples that need to survive intact longer than two years in soil, like erosion control pegs? How can global standards take regional climate differences and agricultural practises into account? Biodegradation testing specifies a test environment to ensure that results are meaningful and comparable. However, it remains a challenge to identify how, for example, biodegradation data measured at 25 °C applies to countries where soil or even air temperatures rarely go above 20 °C. Conversely, products designed for hot and humid climates might degrade sufficiently faster in real life than in a climate-controlled test laboratory. Shelf life labelling and testing is based on testing in the relevant environment and can only to certain extend by supported by accelerated testing. While this is a complicated subject, is a similar approach feasible for the complex and undoubtable important area of biodegradation of plastic? Summary Plastic and ultimately bioplastic use in agriculture and horticulture is increasing. While creating challenges around material use and disposal it will save water and nutrients and will reduce the use of pesticides. Even crop cultivation in deserts will be feasible. Biobased and biodegradable plastic alternatives are a possible answer to the end of life and with that environmental challenges that current fossil-based, non-degradable options create. They offer the combination of sustainable material (biobased) with a sustainable end of life option (compostability) while offering all the benefits of plastics use in the agriculture and horticulture sectors. They can be a vital piece in the transitioning the green sectors of agriculture and horticulture a circular bioeconomy. References [1] https://ec.europa.eu/info/publications/communication-european-greendeal_en [2] https://saiplatform.org/wp-content/uploads/2019/06/190528-report_use-ofplastics-in-agriculture.pdf [3] Carus, M., Renewable Carbon Strategy, bioplastics MAGAZINE, Vol 15, Issue 01/2020, p. 20-22 [4] https://www.plasticseurope.org/en/about-plastics/agriculture [5] Scarascia-Mugnozza, G., C. Sica and G. Russo (2011). “Plastic materials in European agriculture: actual use and perspectives.” Journal of Agricultural Engineering 42(3): 15-28 [6] https://www.european-bioplastics.org/market/applications-sectors/ [7] https://selfecogarden.com/ [8] https://www.mulchfilm.co.nz/ [9] https://biobagworld.com/products/agriculture/ [10] https://www.european-bioplastics.org/new-eu-standard-for-biodegradablemulch-films-in-agriculture-published/ [11] https://www.eplgroup.com/case-studies/leading-edge-bioplasticdevelopments www.scionresearch.com bioplastics MAGAZINE [02/20] Vol. 15 19
