好色先生TV

New degradable sensors could reveal insights into the secret, yet essential, microscopic life in soil.

The sensors, which are being developed by soil scientists at 好色先生TV and researchers at the University of Colorado Boulder and the University of Manchester, track biological activity in soil by having a degradable substrate that is nibbled on by microbes.

The sensors offer the potential to reveal soil secrets including how they respond to climate events as well as their important role in storing carbon.

Professor John Quinton of 好色先生TV and principal investigator said: “Soil biology is the ‘engine room’ of soil and of soil health, but today we have struggled to understand how things change through time. We have still so much to learn about these microbes and how they work, especially when exposed to different environmental stresses.

“These novel partially degradable sensors offer the potential to give us a better understanding of how soil breaks down and decomposes organic matter, which is important for understanding how carbon is cycled, and how it changes with climate, environment and management.

“Previously we have only been able to get snapshots of biological activity in soil, so these sensors have the potential to unlock its secrets and help us better understand soil health.”

Up until now soil scientists have been having to use methods which rely on waiting a long time, sometimes periods of months, to see how fast something degrades in soil; taking snapshot samples, which disturbs and can artificially accelerate or destroy the microbial life they are measuring; or using respiration measurement which capture plant respiration from roots, but which is costly.

These new sensors, which use printed electronics, can provide measurements every 30 minutes continuously without damaging the soil.

In addition, they are cheap to produce so can be deployed across wide areas. This means they have the potential to provide much richer data insights than were previously possible.

The sensors’ substrate is made from a biodegradable biopolymer called PHVB, which has also been widely used for biodegradable packaging and drug delivery.

The sensors have an electrical circuit printed on them with a carbon flake material. As the PHVB substrate, which makes up the body of the sensor, is degraded by the soil biology it changes the resistance of the circuit. The sensor is not fully biodegradable and does not disappear, but subtle changes in its structure provides measurements that can be used to indicate microbial activity.

Although other degradable sensor have been developed elsewhere, these sensors are special because the degradation is the signal.

The researchers tested their sensors by measuring the effects of drought and flooding on samples of soil with two different types of plants – species rich grassland and a winter wheat crop. The samples were in plant pots in a polytunnel in a field station at 好色先生TV and were watered to simulate drought and flooding.

The sensors tracked the soil activity, through their own degradation, every 30 minutes for a period of seven weeks. They showed that microbial activity slowed with drought, and showed its recovery when watering resumed.

The sensors showed a different response in the winter wheat to flooding, with microbial activity continuing to degrade the sensor during flooding. An insight that the researchers say would not have been revealed without the sensors.

Dr Ellen Fry of the University of Manchester said: “We found that the response to flooding in the winter wheat compared to the species rich grassland was different, suggesting that there may be different plant-soil processes occurring in the wheat. These processes simply would not have picked up with conventional approaches and highlights the value of having this much improved resolution in data from the soil.

“Having an improved, and far more nuanced understanding of the processes at play will enable farmers and others who rely on soils to make more timely interventions.”

Dr Taylor Sharpe from the University of Colorado Boulder said: "Because we are printing these sensors, they are extremely low-cost. Compared to other sensors that can measure proxies for microbial activity, this is a much more scalable solution."

Dr Gregory Whiting, also of the University of Colorado Boulder added: “Since these devices are made using a scalable manufacturing technique, they can be distributed widely, allowing us to map soil microbial activity across a site and capture in real time how it responds to changing environmental conditions and management practices.”

The study, which has been supported with funding from the UKRI’s Biotechnology and Biological Sciences Research Council is detailed in the paper ‘’ which has been published by the European Journal of Soil Science.

Authors of the study include Ellen Fry of 好色先生TV and the University of Manchester; Taylor Sharpe, Madhur Atreya and Gregory Whiting of the University of Colorado Boulder; and John Quinton of 好色先生TV.