Tiny sensors created by Irish scientists could help farmers cut pollution

14 Dec 2022

Image: Clare Keogh

The sensor tech lets farmers know in real time what the nitrate levels in the soil are, meaning less fertiliser needs to be spread.

As part of efforts to make farming more environmentally friendly, researchers in Cork have developed new sensor tech to measure the levels of nitrates in soils more accurately.

Nitrates are essential for plant growth, but too much can be a pollutant affecting biodiversity in rivers, lakes and oceans.

The sensors mean that testing for nitrates can be done in real time instead of in laboratories – a process that farmers would have to wait for and that would only reveal the levels at a particular point in time.

The sensors were developed by scientists based at the Tyndall National Institute at University College Cork. This research centre specialises in integrated ICT materials, devices, circuits and systems.

Its work on the farm sensors forms part of an international project that has been looking for more accurate ways to measure soil nitrate levels.

Tyndall is also part of the network of organisations and companies that host Science Foundation Ireland’s VistaMilk research centre for the dairy sector.

The team behind the new sensor tech hopes that it can help farmers reduce the use of chemical fertilisers, which are major environmental pollutants.

Dr Alan O’Riordan, senior research fellow at Tyndall and principal investigator at VistaMilk, said the new sensors represent a real opportunity for farming in Ireland, both in terms of cost savings and environmental impact.

“Fertiliser is expensive and while we’re still using it and waiting for fertiliser reduction initiatives to gain traction, our research will save farmers money. Clearly, less fertiliser means less run-off, means less impact on Ireland’s water quality.”

Complicated development process

O’Riordan also spoke about the “complicated” process of developing the technology for the sensors, which are only around half the diameter of a human hair in size.

Buried in the ground at a depth of 20cm, the sensors communicate data about nitrate levels in soil wirelessly and in real time using Bluetooth and internet-of-things technology.

“We had to deliver a new material for the sensor, we had to make it pH adjustable for better results and we had to stabilise it to prevent ‘drift’ – all while working with something that’s genuinely tiny,” O’Riordan explained.

“We needed to ensure that it could communicate the data it needed to and – as we were going to bury it – it needed to have a decent enough lifespan.”

The sensors have been tested in Romania. “I’m pleased to say that our test chips are still reporting back and that means they’ve survived a full growing season,” O’Riordan added.

“What we’re seeing is real fluctuations in soil nitrate content against the baseline of traditional testing. It implies that traditional fertiliser use – field x has always needed fertiliser, so we’ll keep spreading – can be challenged.”

Sustainable agriculture is one key area of focus for VistaMilk.

In November, researchers at VistaMilk also announced that they had found a way to help farmers breed their cattle based on their “carbon hoofprint”. The team did this by adding a carbon efficiency layer to the selective breeding tool farmers already use for their cattle.

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Blathnaid O’Dea was a Careers reporter at Silicon Republic until 2024.