How do you make the use of plastics in agriculture and horticulture as circular as possible? This question was central to the WUR project Circular Use of Plastics in Agriculture and Horticulture, which was carried out in recent years together with companies and knowledge institutions. Alexander Boedijn (program manager Circular Horticulture), and Wouter Post (project manager Sustainable Plastics Technology) explain how interdisciplinary collaboration yielded surprising insights – and tangible solutions.
The agricultural and horticultural sector uses relatively little plastic (around 3% of global plastic consumption), but the impact is significant: many applications come into direct contact with organic material and/or growing media, making reuse and recycling difficult. "The impact due to pollution is very high," Post explains. "That makes it a very interesting sector to look at how we can make plastic use more sustainable."
Sector-wide issues and tangible solutions
The project consisted of two tracks: seven participating companies worked on real cases, in which sustainable plastics were developed and tested in realistic cultivation conditions. Post: "We looked at various end-of-life routes, such as recycling, industrial composting or biological degradation in the soil." Various new products were developed for this, such as compostable substrate bags or degradable turf nets.
At the same time, sector-wide themes were investigated, such as the question of whether plant viruses can hinder recycling. Boedijn: "It is a widely shared feeling in the sector that recycled products can carry viruses. We wanted to see whether this also happens in practice, or whether this was an unfounded fear." The fear turned out to be justified. "The research shows that viruses do indeed survive at standard recycling temperatures in some cases. This can therefore have consequences for cultivation safety. The next step is to develop an economically viable solution."
Helping growers to make circular choices
In addition to technical innovation and research, the project also wanted to offer practical tools to the sector. A decision tree was developed that helps growers choose the right type of plastic, tailored to their application and the expected end-of-life scenario. The researchers also gathered information about legislation, regulations and existing sustainability frameworks. "This helps growers to better inform themselves so that they can make the right choice for their situation. It is a foundational document for growers, suppliers and policymakers so they can make their choice for a specific product and application better informed. You don't have to start from scratch", says Post.
Connecting disciplines leads to real breakthroughs
What makes the project special according to the researchers is the intensive collaboration between different disciplines. Post: "Virology, materials science, cultivation knowledge and systems thinking all came together. That worked really well. Today's major issues can only be solved with multiple disciplines, that's where the real breakthroughs lie." Boedijn agrees and clearly sees the added value of a large multidisciplinary knowledge institute such as WUR: "We see that as WUR we can be a one-stop-shop to solve very complex problems together with the entire value chain."
Frontrunners work as trailblazers
Although not all questions have been answered, the researchers and project partners have taken a major first step. "We have shown that it is possible," says Boedijn. "It is possible to use plastics more sensibly in horticulture. We also see that there are real frontrunners throughout the chain who want to invest in sustainable solutions." Post: "Some companies from the project are now continuing with commercialization of the prototype products, such as the substrate bags." According to both of them, drawing up a sector-wide covenant, such as the one focused on peat reduction, is therefore a logical next step for the sector.
The entire value chain needs to be involved
For many growers it has become clear: making products and processes more sustainable is not only something you do within the greenhouse, but throughout the entire product chain. Boedijn: "And with this project we have shown how Wageningen University & Research can be a good partner for this. We have knowledge and a network available throughout the entire chain: from raw material to end-of-life." Post adds: "That makes this research, and WUR, truly unique: we can bring together entire playing fields and develop a solution at chain level based on that. And then it really starts to work."
