Professor Megan Povey | Sounding out the Soil

The Global Food and Environment Institute (GFEI) is delighted to share with you the recording of our November 2022 webinar ‘Sounding out the Soil: using acoustics to characterise and measure the physical properties of soil'.

During this talk, Professor Megan Povey highlighted the findings from her research in this area.

At the University of Leeds Research Farm, we work with academic and industry partners from across the UK to co-develop high-quality research programmes that address modern agricultural challenges.

Intensification of agriculture is destroying soil, either through the incorporation of plastic encapsulants for herbicides and insecticides, or through continual ploughing and reseeding with monocultured crops and the abandonment of crop rotation. Some estimate that globally, only 50 cycles of harvest are left in the soil whilst current agricultural practice continues. Healthy soils are a complex combination of mineral particles, bacteria, fungi, organic matter, air, and water:

Plant roots penetrate between the mineral particles which are bound together by organic matter and incredibly, growing roots emit chemical signals which promote the growth of nearby bacteria, easing the passage of the roots between the mineral particles. By sending a pulse of ultrasound between two transducers in contact with the soil, we can learn a great deal about the soil structure. For example, the speed of sound through damaged soil comprising mostly mineral particles (in effect a powder) will be around 10 x slower than through healthy soil.

An ultrasound sensor for testing soils has been integrated with an agricultural robot as part of the Food Supply Chain Tracing and the MARS (Multi-sensor Agricultural Robot for Soils) project. Preliminary results suggest that the sensor will measure bulk modulus, porosity, mobile water content, and the depth of cracks in the soil. The ultrasound sensors are not too expensive, are very robust, and do not necessarily require a robot to carry them as they are very portable. They also have the potential to be used in locations throughout the world, and so could contribute to soil health in developing countries, essential to the development of sustainable agriculture worldwide.

Through automation of the soil testing instrument and combining the measurements with other modalities such as Gamma Ray Detection (In collaboration with Patrick Stowell at Durham University), we expect to transform the science of soil testing.

The seminar was chaired by Professor Steven Banwart, GFEI Director, University of Leeds

#WorldSoilDay: 5 Dec 2022