Agricultural plastic is a small percentage of Europe’s total plastic consumption, but the harm that products like mulch films can do is devastating. Solutions are on the way. Among them are upcycling and biodegradable materials.
“The younger generation of farmers is more attentive to the environment,” Pedro Pablo Diez is optimistic about the responsible use of plastics in agriculture. He is in charge of quality control, R&D, and the environment at Solplast, a leading manufacturer of this kind of product in Spain. Among other things, they produce mulch films, a widely used and yet controversial material.
While agricultural plastics, or 'agri-plastics', make up for just over 3% of Europe's total plastic consumption according to Plastics Europe, their potential for significant and largely unquantifiable harm is a cause for concern. Mulch films, in particular, are currently under intense scrutiny.
Mulching is an ancient technique for improving soil quality and protecting plants. In the last 60 years, the use of plastic—namely polyethylene, or PE— for mulching has spread globally. Mulch films have multiple functions, explains Fuensanta Monzó, project manager of the EU project Agro2Circular: “They are used by farmers to cover the crops to protect them, but also to prevent water from evaporating, and there are also disinfection films that are used to cover the soil when it's disinfected before the new cropping period.” This means they come in various types, colours, dimensions and thicknesses.
The problem is that if the film is not completely retired after use, the effect is counterproductive: microplastics (MPs) are absorbed by the soil, which gets contaminated and, at the same time, its productivity decreases. In addition, “For the lighter films - continues Monzó, – wind and rainwater flows transport it to the rivers and seas, so there is not only soil contamination but environmental contamination.”
All this is without considering the issues related to waste disposal. A recent report by Plastics Europe informs us that agriculture achieves a recycle rate of over 37%, well ahead of other plastic applications when implementing a circular economy. Yet, there are issues, complain ONGs. Lauren Weir from the Environmental Investigation Agency speaks of “mismanagement and illegality” when it comes to waste treatment, especially in the UK. Still, even in the EU, where there are laws at the local level, “There's definitely more unity that might be required in that sense.”
Even where recycling is mandatory, complains Abelardo Hernández, “Sending plastic to recycle is very expensive.” This is because the recycling plant has to separate the plastic from the soil and wash it, which is costly. Hernández is an engineer at Proexport, a Spanish association of producers-exporters of fruits and vegetables.
So, if mulching films has all these downsides, why do farmers keep doing this? “Mulch film is essential for the development of agriculture, says Diez, because it safeguards water, reduces the use of pesticides, enhances crop development, allows a quicker and more efficient crop growth, and, of course, protects the soil. Without plastics, the development of agriculture probably would not be the same.”
“Industrial agriculture,” specifies Weir. “Of course, this is industrial agriculture,” agrees Hernandez, “the agriculture that allows you and me to eat.”
In any case, mulching films will not disappear overnight; at the same time, the EU aims to reduce microplastic releases by 30% by 2030. Solutions are therefore urgently needed.
Although recycling is on the right track, there are problems, especially with the disinfection films, which are multi-material, being made of PE and other polymers. Projects like Agro2Circular are working on upcycling this material, that is, “Improving the final performance of the plastic that the recycling plants are obtaining - explains Monzó - by making the different plastics that composed these multilayer films compatible, using different kinds of additives.” A blend is obtained from this process with improved mechanical properties, which can be more easily used to produce new films or other plastic products for different applications.
Another solution which is being explored is the production of biodegradable plastic, which doesn’t need to be removed after use because it is supposed to disappear into the soil without damaging it. Unfortunately, biodegradable plastic has given some problems in the past. According to ECOS, the standards set out by the EU are not strict enough. “We had problems with biodegradable films because we were told they would disappear, but they didn’t,” remembers Hernández. “We started working on this problem in 2018, and since then, the film market has changed a lot. Now, there is a new standard, and you can be sure the film will be biodegrade in less than two years.”
However, the research is still ongoing. Agro2Circular is at a good point, reveals Monzó: they are currently upscaling the technology to obtain enough material for the end users to test the different blends they are obtaining, and they are testing the biodegradability of the final blends. “There are already some commercial biodegradable plastics in the market, - she concedes, - but they have a high rate of petrol-based plastic. The plastic we are producing is bio-based; it comes 100% from renewable sources. Also, the plastic that we are producing has more biodegradability.”
But there are still challenges to overcome. The project now focuses on improving the mechanical properties of biodegradable plastic, like resistance. And the problem of the costs remains: “Biodegradable films are at least twice more expensive than PE”, says Hernández. And he adds: “I don’t understand why we are looking to use less petrol and yet the petrol-based products cost less. It doesn’t make much sense”. Diez, on the other hand, remains optimistic because he thinks that the market will work out its issues by itself eventually: “Now production is increasing, and soon these differences in cost will be balanced,” he predicts gleefully.