KAIST creates naturally decomposing 'agricultural plastic' using fallen leaves

In a significant stride towards sustainable agriculture, researchers at KAIST have successfully transformed a common environmental nuisance—fallen leaves—into a valuable resource. A team led by Professor Myung Jae-wook has developed an innovative biodegradable agricultural mulch film using these leaves, presenting a promising solution to the pervasive problem of plastic waste in farming.

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This research is significant in that it has transformed fallen leaves, which were simply discarded, into functional materials that can protect the agricultural environment.

The conventional plastic mulch films, typically made from polyethylene, pose a considerable environmental challenge. Their difficult collection after use and the residual fragments that break down into microplastics contaminate soil and harm ecosystems. This new 'leaf film,' developed using an eco-friendly solvent process based on citric acid and choline chloride, extracts nanocellulose from the leaves. This is then combined with polyvinyl alcohol, a biodegradable polymer, to create a composite film entirely through water-based manufacturing, minimizing environmental impact.

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It can be utilized as a sustainable agricultural plastic alternative through fallen leaves that do not compete with food resources and a water-based process.

Performance tests confirm the leaf film's viability in agricultural settings. It effectively shields crops from harmful UV radiation and maintains soil moisture, showing comparable or even superior results to traditional films. Crucially, its biodegradability is significantly faster than existing alternatives, breaking down substantially within 115 days without releasing any phytotoxic substances that could harm plant growth. This ensures that the soil remains healthy and fertile for future cultivation.

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The developed film showed effective UV blocking and a moisture retention performance that suppressed soil moisture loss to about 5% over 14 days.

This breakthrough, published in the prestigious journal 'Green Chemistry,' not only addresses the plastic waste issue but also valorizes a readily available, non-edible biomass. As reported by The Hankyoreh, this research offers a sustainable pathway for agricultural practices, reducing reliance on petroleum-based plastics and contributing to a circular economy. The development underscores KAIST's commitment to pioneering environmentally conscious technologies that have the potential for widespread positive impact.

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In soil conditions, the developed film decomposed by 34.4% in about 115 days, showing a faster decomposition rate than existing biodegradable films.