Revolutionising Agriculture: Could Plastic That Dissolves in Soil and Seawater Transform Farming?

Introduction 

Plastics are indispensable in modern agriculture, helping to improve yields, protect crops, and simplify farm operations. But their environmental cost has become impossible to ignore. Each year, agriculture generates an estimated 6.5 million tonnes of plastic waste worldwide, much of which ends up in landfills or pollutes ecosystems. Soil contamination from microplastics is also a growing concern, with studies suggesting that up to 30% of soil pollution comes from agricultural plastics.

A groundbreaking innovation from RIKEN and Tokyo University might offer a solution. Their new plastic dissolves completely in seawater within weeks and breaks down in soil in just ten days. While this material has incredible potential, its current properties may require further adaptation to meet agricultural needs. Let’s explore how this plastic works, the practical benefits it could offer farmers, and what challenges remain.

The Science: How It Works

The plastic developed by RIKEN and Tokyo University is designed to degrade through natural processes, converting into harmless molecules like water and carbon dioxide. In soil, microbial activity accelerates the breakdown process, leading to complete decomposition in just ten days. This eliminates the long-term residue and microplastics that are the hallmark of conventional plastics.

For seawater, the material breaks down over several weeks, making it ideal for reducing marine pollution caused by fishing gear, packaging, and agricultural plastics washed into waterways.

However, the ten-day breakdown period in soil, while advantageous for waste management, presents challenges for agricultural use, where many applications require durability over weeks or months.

Where It Fits: Practical Agricultural Applications

The biodegradable plastic offers realistic and immediate benefits for specific areas in farming:

1. Mulch Films That Disappear After Harvest
Mulch films are widely used to retain moisture, suppress weeds, and regulate soil temperature, covering millions of hectares globally. However, their removal at the end of the season is labour-intensive, costly, and environmentally problematic.

A mulch film made from this dissolvable plastic could decompose directly into the soil after use, saving farmers the effort and cost of retrieval and disposal. The ten-day breakdown time is well-suited for crops that require seasonal mulch, such as lettuce, spinach, or strawberries, where films are typically removed shortly after harvest.

Potential Impact: In the EU alone, around 80,000 tonnes of agricultural plastic are used annually, with mulch films being a major contributor. Dissolvable films could prevent thousands of tonnes of plastic waste each year.

2. Eco-Friendly Packaging
The agricultural supply chain depends heavily on single-use plastic packaging for seeds, fertilisers, and agrochemicals. These materials often accumulate on farms or in landfills due to limited recycling infrastructure, particularly in rural areas.

This dissolvable plastic could replace single-use packaging, ensuring that bags and containers naturally degrade if left in the environment. The ten-day soil decomposition period makes it ideal for packaging, as it won’t linger in the soil or contribute to long-term pollution.

Potential Impact: With over 12 million tonnes of plastic packaging used globally each year, even small changes in agricultural packaging could lead to significant environmental benefits.

3. Disposable Irrigation Components
Plastic components in irrigation systems—such as drip tapes or temporary pipes—often degrade over time and release microplastics into the soil. Dissolvable plastic could replace these disposable components for short-term irrigation needs, such as seasonal crop watering.

The rapid degradation time would make it ideal for temporary irrigation setups, where farmers can leave the components in the field without worrying about residue or contamination.

Potential Impact: A report by FAO estimates that microplastic pollution in soil could be 23 times higher than in oceans, much of it stemming from degraded agricultural plastics. Reducing this source of contamination would be a major win for soil health.

The Challenges: Adapting for Broader Use

While the potential benefits are promising, there are significant hurdles to overcome before this plastic can be widely adopted in agriculture:

1. Extending Durability
The current ten-day degradation time is too short for applications requiring long-term use, such as mulch films for slow-growing crops like tomatoes or perennial crops like berries. Extending the lifespan to several months without compromising biodegradability will be crucial for broader adoption.

2. Cost Competitiveness
Biodegradable plastics generally cost 20–50% more than conventional plastics due to more complex manufacturing processes. To compete with traditional materials, production costs must be reduced through scaling up and technological improvements.

3. Adapting to Varied Environments
Degradation rates may vary depending on soil type, temperature, and microbial activity. More research is needed to ensure consistent performance across diverse farming environments.

Why This Matters: Environmental and Economic Benefits

If adapted successfully, dissolvable plastics could provide tangible benefits to both farmers and the environment:

Reducing Plastic Waste: Agriculture accounts for a significant proportion of the world’s plastic waste. Dissolvable materials could drastically reduce the volume of plastics entering landfills or polluting soil.
Protecting Soil Health: By eliminating microplastic contamination, these materials could support healthier soils, which are essential for sustainable farming and food security.
Lower Disposal Costs: Farmers often face high costs for removing and disposing of used plastics. Biodegradable alternatives eliminate this expense, saving money and labour.

A Step Towards a Sustainable Future

The development of dissolvable plastic is a powerful step forward in addressing the global plastic crisis. While it may not yet be a perfect fit for all agricultural uses, its potential is undeniable. By refining its durability and expanding its applications, this material could play a pivotal role in creating more sustainable farming systems.

Imagine mulch films that vanish after harvest, irrigation tapes that disappear with the season, and seed packaging that leaves no trace behind. With innovations like this, we could see a future where farming practices align more closely with environmental stewardship.

Conclusion

The journey is just beginning. As researchers refine this technology, collaboration between scientists, policymakers, and the agricultural industry will be critical to its success. Future versions of the plastic could be engineered with variable lifespans, tailored to the unique needs of farmers.

For now, this dissolvable plastic offers a glimpse into what’s possible—a world where the tools we use to grow food also protect the earth for future generations. It’s not just about reducing waste; it’s about rethinking the way we work with nature, one innovation at a time.

*By Anne Hayden MSc., Founder, The Informed Farmer Consultancy.