Protecting peat to protect the planet
Sally Le Page took a walk through this endangered habitat to find out more about the history and science of peat bogs and what is being done to save them...
Sally - I’ve managed to escape the home office to go on a little walk through one of the key ecosystems when thinking about climate change - peat bogs. Here in Cambridgeshire we have a vast expanse of lowland peat called the Great Fen, where I am now, part of the Fens that represents 27% of England’s peatlands. Peat is a remarkable substance, and we're not just talking about anyone called Peter! Peat is a type of soil that forms over thousands of years in wet, boggy conditions. Moss plants like sphagnum moss photosynthesise and absorb carbon dioxide in the air, using that carbon to grow. In normal soils, when plants die, microbes use oxygen to break down the dead plant material releasing some of that carbon dioxide back into the atmosphere. But because peatbogs are so waterlogged, there isn’t enough oxygen for the moss to break down and so as long as the peat stays wet, the carbon is trapped.
Sally - This makes our peatlands incredibly important stores of carbon. Peatlands cover only 3% of the world’s land surface, but hold 25% of the global soil carbon. And the UK has more peatland than vast majority of countries around the world - 10% of our land area is covered in peatland habitats. It’s estimated that there is over 3 billion tonnes of carbon stores in the UK’s peatlands, which is equivalent to all the carbon stored in the forests of the UK, Germany and France combined.
Sally - There we go. Over this little wooden bridge.
Sally - Now, not only is the peat disappearing into the atmosphere through oxidation, the dry peat can be literally blown away in the wind. As a result of all of this the land is sinking.
Sally - Here we are, this is where I was walking to. I am stood in front of two, what look like Victorian lamp posts on the edge of a wood in the middle of nowhere. Very bizarre. They are about three of me tall; what's that, four metres tall? And they're called the Holme Posts. As I get closer I can see these black labels with years on them, a bit like when you mark off your kids' height on a door frame to measure how much they're growing, but unfortunately these markers are not measuring growth. Quite the opposite. The first one at the very top I can just about make out says 1848. That is just the year before they drained the mere and with an awful lot of foresight they pushed these posts down as far into the ground as they could go until they reached the solid clay layer below. Back in 1848 the top of this incredibly tall post was level with the ground. Then as they drained the mere, I can see the next marker down is 1860, that's already a good one and a half, two metres down. That drop in the level of the land is mostly from all of the water being removed. Then we go down further 1870, 1875 we're now at my eye level, 1892 we're at my belly button. Then of course my feet are currently at ground level in 2021. That is four metres worth of carbon stored in that peat that is now released into our atmosphere.
The Wildlife Trust are behind restoring this Great Fen for biodiversity, but they're also researching ways in which we can use the land productively to grow food and building materials without draining and degrading the peat soil underneath. A few days earlier, Sally travelled down the road to an experimental farming site on the Great Fen called Water Works to find out more from restoration manager, Lorna Parker.
Lorna - The project is called the Water Works project, and it's an exciting opportunity to showcase a new form of farming. Up to two centimetres of soil lost in terms of land height every year. In places that soil is already very shallow, but even in the deeper areas, you might be looking at another 80 years of farming and then no more peat soil left anyway, and we need to find another choice.
Sally - What would the farmers do when the peat runs out?
Lorna - Underneath the peat is a layer of really heavy clay. So it's much harder to farm. And before you get there, a lot of this peatland is actually quite acidic as well because we were at the seaside about 5,000 years ago. There's all sorts of geology under our feet that make it very complicated to farm.
Sally - Either it's 80 years of farming vegetables, business as normal, and then kind of farming crisis for this area. What's the alternative?
Lorna - That's what we're hoping to show. We're kind of trying to demonstrate a new form of farming, which will look at crops that you can grow in wet soil. We can trap that carbon, lock that carbon back in, but also hopefully produce food, fuel, fibre and medicines.
Sally - This is the fab word 'paludiculture'.
Lorna - It's a good one isn't it? It will be a word that most people won't have come across before. 'Paludi' is 'swamp', so it's swamp agriculture. What we're going to do is go for a walk on our wet farming pilot project, the Water Works project, and have a look at some of the new crops that we're going to grow and hopefully excite you about the possibility of the things we can do with those crops in the future.
Sally - I'm already very excited. The cows are already very excited. Let's go. We've walked over some little raised strips. We walked over some ditches, where are we now?
Lorna - Okay, so we're in the corner of one of our new wet farming beds. This one we're sat in at the moment is what we're hoping will be a future food crop for the fens, and which is manna grass. It's a cereal crop, which would need some crop development, but could be a porridge or a sort of flour.
Sally - I'm looking at one of these seed heads now. I mean, it's not much to look at compared to an ear of wheat for example. You can barely see the seeds. What will the seeds look like?
Lorna - They'll be small, like a kind of millet-type grain, that you could have in your posh ancient grain porridge for example, or you could mill it into possibly low gluten flour.
Sally - You've got to ask, what does it taste like?
Lorna - I don't know yet, because this is our first year. So we haven't harvested any. I think the seed is so precious at the moment, we'll probably grow more plants with it rather than eat it.
Sally - You're going to spend years of work creating this food that you don't even know tastes any good?
Lorna - I hope so. We can add a jam to our porridge. I'm sure it'll be fine.
Sally - When you're thinking of plants that can feed lots of people in wet soil, the automatic choice would be rice. So why aren't you growing rice here?
Lorna - We're looking at rice. The climate in the UK is not ideal for rice at the moment, but you know, with global warming it's going in the right direction. Our plant nursery is actually looking at different strains of rice to find ones which grow in the most similar climate to what we have here.
Sally - As you can probably hear, this field is a lot wetter than the other one.
Lorna - Yeah. We've come to have a look at our bullrush field.
Sally - And what can we use bullrushes for?
Lorna - Bullrush is pretty epic as well actually. It's got a structure when it grows, where it traps lots of air inside its stem. It can be absolutely fantastic for fibreboard, so for construction materials that insulate at the same time. For cavity wall filling, you can shred it and blow it in, in place of artificial products. It would be really exciting, I think, to grow products and then build local houses from something that's sourced only a few miles away.
Sally - Yeah, totally.
Sally - We are next to probably one of the biggest plots, I would say, of the ones we've been to and it's covered in - very familiar to any allotment grower - a weed membrane. What is going to be here?
Lorna - Okay. So we've got about 150,000 plugs of this tiny bog moss that we're going to plant of several species underneath the mesh, and it will grow into a sort of carpet of green under there which will be a really good crop for us to harvest and lock that carbon in the soil.
Sally - Growing moss as a crop. How is that going to be useful?
Lorna - There's lots of ways. I could talk for hours just about the moss. Moss is really exciting. One of the most exciting things that we're hoping to do with the moss here is grow it and harvest it as a substitute for compost, for growing vegetables.
Sally - Right now there's been this big move of not buying compost that's got peat in it, right? Is this what's going to be in the bags of compost instead?
Lorna - We're hoping to go bigger than that. We're hoping this will be what growers of vegetables that you eat in the supermarket are going to use to grow their small lettuce plants, for example, rather than buying in peat from peat that's been harvested from peat bogs in the wild.
Sally - Wow. Not only will this moss stop people digging up the peat for the sake of the peat. It will also stop the peat here from drying out and we still get vegetables.
Lorna - Absolutely. The moss is amazing because it can control its own environment. It can control its own water. It can control weeds. It's antibiotic. It's super absorbent. It's like a hero plant.
Sally - You really are in love with this moss aren't you.
Lorna - It's a bit of a worry, isn't it?
Sally - If you had a magic wand, what would you do with all of the peat bogs and former peat bogs in the East of England?
Lorna - Most of the peat here is farmed. I would like to see ways that we can use it productively because that's a really important part of the local economy and the local culture, but in a way that can protect it forever. If we don't do something now it will be gone for future generations. If we can do that in a sustainable way, which has all these other benefits and build our houses from it, then what's not to like about that.