Osaka University showcased biodegradable soil moisture sensor

A research team from the Institute of Scientific and Industrial Research (SANKEN) at Osaka University, led by Assistant Professor Takaaki Kasuga, has developed a groundbreaking soil moisture sensor that significantly contributes to sustainable agriculture. The sensor, primarily composed of eco-friendly materials such as paper, natural wax, and tin, is designed to be biodegradable, blending seamlessly into the soil after use.

The innovative sensor functions by emitting the detected moisture content of the soil as heat, which can be remotely captured via a thermal camera. This method allows for the simultaneous acquisition of both the sensor’s location and the soil moisture content. The simplicity of the sensor’s design, combined with a wireless power supply and image recognition technology, enables it to degrade naturally in the soil while maintaining its sensing functionality and transmitting crucial data, including location information.

One of the key features of this new sensor system is its ability to convert various environmental parameters, such as temperature, humidity, and light, into digital signals. Traditional sensors, often made of non-degradable materials like copper and petroleum-based plastics, pose environmental risks and are challenging to recover in outdoor settings. In contrast, the new sensor developed by Kasuga’s team is primarily made of biodegradable components like wood-derived nanocellulose and natural wax, which can be broken down by microbes.

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The sensor’s design includes a paper substrate with tin wiring, a carbon heater, and a natural wax coating. It is powered wirelessly, with the power supply also heating a mounted heater. The heater’s temperature varies with the soil’s moisture content, enabling precise measurement of soil hydration levels through thermal imaging.

After their functional lifespan, these sensors can be tilled into the soil, where they naturally degrade and release fertilizer components, thereby stimulating crop growth. This dual functionality positions the sensor as a potential game-changer in precision agriculture, offering both environmental monitoring and enhancing soil fertility.

Professor Kasuga envisions these sensors as an integral, unobtrusive part of the agricultural landscape, akin to fallen leaves, emphasizing the use of naturally existing materials like cellulose nanofibers and beeswax. The team is committed to field testing and further improvements to ensure the practical applicability of these sensors in real-world agricultural settings. The research findings were published in the international academic journal Advanced Sustainable Systems on October 17, highlighting the sensor’s potential as a significant advancement in sustainable agriculture.

Source: Science Japan