Biodegradable soil sensors aiding in the push for clean agriculture

Pioneered from a collaborative effort between the University of Glasgow and the Łukasiewicz Institute of Microelectronics and Photonics (IMiF) in Poland; the sensors are made from materials that naturally degrade into nutrients, effectively turning into fertiliser and contributing to soil health once no longer in use.

Biodegradable soil sensors for digital agriculture

These front-end sensors are integrated with standard electronic components to monitor key indicators of crop health whilst its modular design allow the reusable parts of the system to be preserved, significantly lowering the environmental burden usually associated with sensor-based systems. Environmental impact assessments conducted by the researchers suggested that this approach supports more sustainable practices in electronic system design, cutting potential e-waste.

The team took this hybrid architecture to the field of digital agriculture – an emerging method that involved attaching networks of sensors directly to crops to monitor conditions and growth. As global food demand is expected to increase by 70% by 2050, digital agriculture is offering a scalable, data-driven solution. The concern here however is that existing sensors used in this approach have typically relied on non-recyclable components, contributing to rising volumes of harmful electronic waste.

To tackle this the researchers designed a sensor system consisting of a small, reusable electronic module combined with a biodegradable sensing patch. These patches were produced using a screen-printing technique similar to t-shirt printing, a low-energy, low-cost process suitable for large-scale manufacture.

The sensor itself was constructed on a biodegradable polymer base with conductive tracks printed using a graphene-carbon ink, while the sensing layer is composed of molybdenum disulfide. Every material used in the patch will eventually break down into nutrients that support plant growth.

The patches are able to detect changes in pH and temperature—often linked to crop infections—and wirelessly transmitted the data to a central computing system. In laboratory tests, the sensors reliably measured pH values across a range from pH 3 to pH 8 over a two-week period. The team also demonstrated their ability to detect traces of ethephon, a widely used plant growth regulator that poses a contamination risk to water sources.

Once the sensors reach the end of their useful life, they return to the soil, where they decompose into beneficial primary and secondary nutrients.

Addressing a growing problem

Dr Joseph Cameron of the University of Glasgow’s James Watt School of Engineering noted that ‘ensuring stable food supplies was a major global concern, with over 800 million people currently affected by malnutrition.’ He suggested that digital agriculture could play a vital role in addressing that issue.

Andrew Rollo, also from the James Watt School of Engineering, added that their system could help reduce the carbon footprint associated with digital agriculture. The reusable module minimised the impact of components made from less environmentally friendly materials, while the compostable sensors contributed directly to crop nourishment.

Their analysis showed that replacing only the biodegradable component every three months could lower the system’s environmental footprint by 66%. Over five years, this figure rose to 79% when compared to replacing full devices each time.

Professor Jeff Kettle, who led the research, emphasised the need for sustainable solutions in digital agriculture. He pointed out that ‘80% of the world’s electronics currently ended up in landfill, leading to widespread environmental and health issues due to toxic materials.’

The group plans to expand the sensor’s capabilities to detect other environmental factors, including so-called ‘forever chemicals’ like PFAs, which pose persistent threats to ecosystems.

Study details

This work formed part of the wider TESLA project (Transient Electronics for Sustainable ICT in DigitaL Agriculture), a £1.8million initiative funded by UK Research and Innovation and CHIST-ERA. TESLA brought together partners from McGill University in Canada, Tampere University and VTT in Finland, Łukasiewicz IMiF in Poland, and CSEM in Switzerland.

The project aimed to develop an integrated system powered by sustainable solar cells and supercapacitors, with the goal of delivering a fully eco-friendly platform for precision agriculture.

The research was published in ACS Applied Electronic Materials under the title Hybrid agricultural monitoring system with detachable biodegradable and printed pH sensor with a recyclable wireless sensor network for sustainable sensor systems. It was co-authored by researchers from Łukasiewicz IMiF and the Central South University of Forestry and Technology. Funding was primarily provided by the Engineering and Physical Sciences Research Council (EPSRC) and the São Paulo Research Foundation (FAPESP).