The impact of plastic on the environment goes beyond mounds of trash, lost plastic bags in a field, or a tortoise stuck on a plastic wrap. If you have followed the ReBIOlution project for a while, you are likely familiar with the term “plasticulture”. It refers to a type of agriculture using large quantities of plastic. And that plastic may pollute the environment, but it hurts more than meets the eye. In this article, we look towards the impact of plastics and biodegradable plastics on the smallest living organisms in agriculture: microbes.
Why should we care about microbes in agriculture?
Microbes have a hand in everything related to soil and agriculture. The classification of “soil microbiome” refers to the microbial community that lives in soil. They decompose organic matter, cycle nutrients, suppress pathogens, and even help plants withstand stress. Plants and microbes often thrive together, with symbiotic relationships where fungi in roots help plants get the nutrients needed from the atmosphere. And even if they don’t help each other, plants and soil microbes are neighbours. A thriving soil microbiome means healthier crops, higher yields, less fertilizer needed, and resilient farms.
How do plastics affect the soil microbiome?
It should come as no surprise that covering the soil with plastic mulch, covering tents with plastic insulation to make greenhouses, and other plasticulture practices, all affect the soil microbiome, and often not for good.
Soil covered with plastic mulch may have a shift in acidity and pH, as microbes and plants release chemicals into the atmosphere, but they become trapped by the plastic. The increase in heat might also drive microbes to stress and release harmful molecules, or for only certain species to thrive, creating an imbalance. This can result in problems for plant growth.
When the plastics are exposed to the sun and water, harmful chemicals might leach into the soil. And when plastics break, they can contaminate the soil with microplastics and even more chemicals. This can all be harmful for microbes that often help plants grow, or make harmful microbes thrive.
Are biodegradable plastics gentler with the soil microbiome?
When farmers use biodegradable plastic films as mulch, the initial effect is much like conventional plastics, altering soil temperature, moisture, and gas exchange. Then, biodegradable films are tilled into the soil after use, where they become a direct food source for microbes.
While most studies suggest that biodegradable plastics do not cause acute toxicity to soil organisms or plants, there are still questions left to answer. These plastics are broken down by microbes, but very small particles may remain from some types of biodegradable plastics. There is also evidence that constant use of biodegradable plastics can increase microbial biomass, as they degrade the plastic, potentially changing the microbiome and soil properties over time.
The ReBIOlution approach
At ReBIOlution, we work to ensure that our materials both solve the problem of plastic pollution and also support soil health. We do this by performing rigorous testing of our biodegradable plastics in soil samples.
First, at smaller scales, we test how they degrade in soil and water, and how they can be recycled. If and when we find them safe for the environment, we move on to larger testing sites.
We want to comply with the European regulations as well. The European Union and other regions are tightening regulations on plastic use in agriculture, demonstrating the soil safety of new materials is more important than ever. Certifications such as EN 17033 require evidence that biodegradable plastics do not harm soil health or biodiversity. At ReBIOlution, our science-based approach helps us meet these standards. It also aims to build trust with farmers and consumers seeking truly sustainable solutions.
The true ReBIOlution: making plastics that help microbes
So where does all this science lead us? For us, the ultimate goal is to create materials that do more than just disappear. They should actively benefit the soil microbiome and, by extension, the entire agricultural ecosystem. Imagine bioplastics that deliver nutrients to beneficial microbes, suppress soil-borne diseases, or even enhance plant growth.
That may seem far-fetched, but it is not. By weaving nutrients, molecules that boost growth from the right microbes, and slow-release pesticides into biodegradable plastics, we can achieve all this. That is the vision driving innovation at ReBIOlution.
Minute matters
Even things too small to see with our eyes are crucial for a healthy and sustainable agriculture and planet. The intersection of soil microbiome and biodegradable plastics is a cornerstone of sustainable agriculture. At ReBIOlution, we focus on soil health in our material design, testing, and deployment. We want to stop plastic pollution and help agriculture from its base and roots. The most critical part of anything is its foundation. Let’s not forget about the soil and the microbes that allow plants to grow healthy and feed us.
Author: Darío Sánchez