A football themed presentation into how long arable soils will last in the UK wins an early career researcher a top prize from the British Society of Soil Science
“Soil is a finite resource like everything else. said Dan Evans, a first-year PhD student at Lancaster University’s Environment Centre.
“I’m interested in how long we have left until our soils are eroded to bedrock: the UN says 60 years but for some regions I estimate it could be less ”
Dan is testing his theory by measuring how fast arable soils are eroding, for which we already have a lot of UK data , and how long it takes to produce arable soils - which hasn’t yet been quantified.
“My study is the first in the UK to quantify soil production rates for arable systems: we have lots of measurements on mountains and desert regions globally, but don’t have any on arable soils, the soils matter the most.”
Dan’s prize - including a trophy of an ornamental spade - was for the best 10-minute oral presentation at the British Society of Soil Science Early Career Researcher’s conference. His talk, 'Soil Productive Lifespans: Reviving the Role of Pedologists in Contemporary Soil Science’, used a footballing metaphor to illuminate his argument.
“We lose 30 football pitches worth of soil to degradation every minute across the globe. Recently we’ve realised that to score goals for food security we also need to score goals for soil security.
“There are lots of different players on the pitch all working together on these goals, but the soil production scholars are on the bench - how do we get them on the pitch working with everyone else?”
His passion for arable soils stems, he believes, from his childhood in Norfolk’s farming country.
“Soil benefits us in so many ways. Not only do we grow our food in it, but it ensures our ground water is fresh by acting as a natural filter, removing toxins. We need to understand how it operates, and how we can act to conserve it.”
After studying Physical Geography at undergraduate level, he gained a PhD studentship on the Soils Training And Research Studentships (STARS) Centre for doctoral training, based at Lancaster University and involving seven other universities and research institutes.
“Being part of STARS has made a massive difference: I have great relationships with my cohort at other institutions,” says Dan, who has just returned from a STARS training week.
“It means I’m not doing my PhD with just the resources at Lancaster, but I have a chance to go to the other institutions and use their data. If I want a bit of data on soil carbon I can say to a fellow PhD student who’s at Rothamsted Research: ‘you have the longest running carbon data set, can I come and borrow it?’”
Dan is measuring soil erosion and production rates on six sites in the West of England and Wales: three arable systems and three ancient woodland, which is as close to natural sites as he can find, to act as a comparator.
To measure production rates he’s using a complex technique called cosmogenic radionuclide dating, which involves “lots of physics”.
Despite the difficult equations, Dan says that his most challenging task so far has been gaining permission to access the field sites.
“Some sites were owned by people who don’t live there. I ended up looking at land registry data, phoning up post offices and village halls, doing a lot of detective work. And once I knew the owner I had to persuade them to let me take a chunk out of their field - my samples have to come from bedrock.”
Dan is interested not just in how fast soil is produced, but in how it is produced. This involves a whole range of natural processes - weathering bedrock, rotting plant matter and wind deposition - as well as human activity such as adding fertiliser, waste matter and mulch to the soil.
“We need to think about all the different types of contributions, very often scientist will focus on only one aspect,
“If we want to extend the lifespan of our soils we need to think not only about reducing soil erosion, but also about how we might build soils.”
Dan got insight into how this might be done during a field trip to Brazil, for a workshop at the University of Lavras, which has a research partnership with Lancaster University.
“We spent time with a farmer who had done zero tillage over last 30 or so years and built five metres of soil from residue. He went against Brazilian convention at the time and produced really good results. It makes me really optimistic that we can do something to extend the life of our soils: we need to send this message to policy makers.”
Just eight months into his PhD, Dan is very excited about his research, and the opportunities offered at Lancaster.
“It’s been a bit of a whirlwind since I applied last June. Lancaster is such a vibrant place, there’s always something going on and events to attend.”