Sustainable and circular bioeconomy for food systems transformation

Bioeconomy Talks: Plastics waste in agriculture with Richard Thompson and Giulia Carcasci


The Bioeconomy Talks series features interviews with experts on bioeconomy themes that are linked to agrifood systems transformation.

Richard Thompson joined FAO in 2003, following a career in international hazardous waste management. As part of the Plant Production and Protection Division, he steered FAO's work on the sustainable management of empty pesticide containers. Since retirement, he has co-authored FAO's first global assessment of plastics used in agriculture.

Giulia Carcasci has a Master’s degree in Environmental Science from Wageningen University (Netherlands). Her background is in solid waste management and circular economy. In 2021, she joined FAO’s Office of Climate Change, Biodiversity and Environment as agricultural plastics and sustainability specialist.

FAO produced a report in late 2021 assessing agricultural plastics and their sustainability – what does the report say about plastic waste in agrifood systems?

Let’s start with why plastics are used in agriculture in the first place. The reason is simple – they provide many benefits. For example, plastic greenhouses, mulching films and irrigation pipes help farmers reduce water and pesticide use. Plastic-coated fertilizers provide plants with nutrients at the required rate without polluting the surrounding area. Silage films help livestock farmers produce long-lasting and nutritious fodder. And plastic-based fishing gear is tough and durable in harsh aquatic environments.

However, there is a big downside – agricultural plastics pose a significant threat to ecosystems and food security. Most plastics are single-use and persist in the environment for a very long time. In many parts of the world, agricultural plastics aren’t appropriately collected, recycled and disposed of. Plastics left in fields end up being dispersed by wind and rain. They can also degrade into smaller particles and infiltrate our soils, waterways and food chain. In 2019 alone, more than 10 million tonnes of plastic were used in crop, forestry, and animal production, and more than 2 million tonnes in the fisheries and aquaculture sector.

If plastics were once useful in boosting productivity, their presence in soils in large quantities is now posing an unprecedented challenge – studies show that yields can start to decrease due to plastic pollution. Impacts on human health are difficult to ascertain, but the potential for accumulation in the food chain is alarming.

The assessment report identifies ways to improve the circularity and sound management of agricultural plastics based on a 6R model. What does this mean in practice?

Yes that’s right, the assessment report identifies alternatives and interventions to improve the circularity and sound management of agricultural plastics based on the 6Rs (Refuse, Redesign, Reduce, Reuse, Recycle, and Recover). Depending on the application, in practice this could mean: adopting agricultural practices that avoid the use of plastic; eliminating the most polluting plastic products; substituting plastic products with natural or biodegradable and compostable alternatives; promoting reusable plastic products; adopting new business models; improving use practices; establishing and enforcing mandatory extended producer responsibility schemes for collection and sound environmental management; and establishing fiscal measures and incentives to drive behavioural change within the supply chain, and among users and consumers.

Given environmental concerns over fossil-based plastics, are there viable bio-alternatives that could perform some of the useful functions of plastics in agriculture while causing less harm?

To answer that question, it’s good to be clear on the vocabulary. Plastic polymers can come from fossil-based (petroleum) or bio-based precursors; in the latter case, we talk about bio-based plastics. Biodegradable plastics, on the other hand, can be made both from bio-based and fossil-based precursors. Biodegradable plastics can be broken down by naturally occurring microorganisms – such as bacteria and fungi – into water, biomass, and gases. For new bio-based plastics, compostability is also a desired feature.

In some agricultural systems and fishing operations, biodegradable options are particularly recommended for those plastics that cannot be avoided in the first place, that cannot be replaced with reusable or more durable materials, and that cannot be easily retrieved. Options need to be assessed case-by-case using a holistic life-cycle approach and searching to reduce fossil fuel dependency.

Bioeconomy offers promising solutions to improve the sustainability of plastics used in agriculture both upstream and downstream. For example, cover crops can help reduce the amount of plastic waste used in agriculture while delivering similar benefits to conventional plastic mulch, thereby contributing to long-term soil health and supporting a more sustainable and regenerative agriculture. Bioeconomy can also provide solutions to problems arising from microplastics in agricultural soils, which can come from the degradation of larger plastic items (e.g. plastic mulch) or from the application of sewage sludge. Several studies have confirmed the ability of microorganisms and plants to remove micro and nanoplastics from soil or water.

What are some of the barriers to the adoption of more bio-based and biodegradable plastics in agriculture? And how can we overcome these barriers?

We are seeing an increase in the search for alternative practices and products, as more farmers and producers become aware of the issues surrounding the use of agricultural plastics. One of the barriers to the adoption of bio-based plastics in agriculture is lack of end-of-life certification and standards. More studies are needed to better understand the fate and degradability of these bio-based plastics exposed to different climatic and soil conditions. As for biodegradable agricultural plastics, they often come at a higher cost for farmers, who are then incentivized to keep using cheaper and more polluting plastic products.

When it comes to the use of cover crops, the widespread use of plastic mulch can cause the disappearance of precious traditional and local knowledge on sustainable cover crop applications. Lack of access to best practices can drive farmers to adopt less sustainable and more polluting practices, such as using plastic mulch.

Finally, what steps is FAO taking to support a reduction in plastic waste in agriculture?

Based on a recommendation by its Committee on Agriculture, FAO is about to start a consultation process on a new Voluntary Code of Conduct (VCoC) on the sustainable use of plastics in agriculture. This process will support deliberations of the Intergovernmental Negotiating Committee on the United Nations Environment Assembly (UNEA) Resolution to “End plastic pollution: Towards an international legally binding instrument”. Both the VCoC and the UNEA processes are likely to take some time, so stay tuned for updates along the way!

The International Day of Zero Waste is celebrated on 30 March.

Photo: Richard Thompson and Giulia Carcasci



Assessment of agricultural plastics and their sustainability: A call for action (publication)

Plastics in agrifood systems: The good, the bad and the ugly (article)

3 ways to improve the management of agricultural plastics (video)

FAO sustainable and circular bioeconomy (website)

Bioeconomy for a sustainable future (publication)