Truly green kale: farmer Chris Molyneux on soil health
The story of Molyneux kale starts with Chris Molyneux’s great- great- grandfather’s spring greens – a crop that was improved and its seed collected and saved for years. By re-sowing this crop and selectively breeding with kale and cavalo nero, Chris has developed a range of delicious greens that grow throughout the year, whilst caring for the soil that makes this possible.
The Grade 1 soil on my farm in Scarisbrick took between 10 and 30 thousand years to form. Prior to that, Lancashire was covered with ice, which when it retreated, left rhegolith – rock scraped bare by the retreat of the glaciers. Breaking that down and moving it created soil. The soil triangle can be used to work out what to do with different types of soil, by assessing the percentage of different elements – loam, clay, silt, sand. But this is not a fixed picture – soils can be improved.
In the 1970s and 80s, the organic component of soil used to be seen almost as an inconvenience, when best practice was seen as assessing the soil and adding chemical fertilisers. However, we are starting to appreciate now that the organic component of the soil is the most important thing about it! Humus makes up the bulk of this organic component. It’s a relatively inert substance made up of carbon, hydrogen, nitrogen, oxygen and sulphur.
What’s in the soil beneath our feet?
The rest of the organic component is made up of the biological fraction: creatures classified as micro- to macro-fauna. From the tiniest of viruses which infect bacteria to creatures like earthworms. If we look at the amount of life that can be supported on grassland, one hectare can support 16 sheep. Living within the soil, on an arable soil (which probably has the lowest level of organisms), around 5 tonnes of biologicals can be supported – equivalent to 100 sheep. And this level can be up to 10 times higher on long-term grassland – one hectare could provide enough space for 50 tonnes of living organisms within the soil, recycling nutrients, helping to keep carbon locked up in the soil, and improving soil health.
Because of the way we’ve been farming, much of our soil is now in poor condition, because we’ve tended to think of it as an inert object which we need to throw nutrients at in the form of fertiliser in order to increase yield. There are other challenges too: too much cultivation, no rotation, compaction by heavy machinery – also issues of rainfall and drought caused by climate change – making things worse. But we’re now much more aware that we need to work at keeping soil in good condition. A good soil will be friable and finely divided. Heavy, lumpy soils encourage anoxic conditions in which encourages different bacteria and fungi which are detrimental to some of the things we need to grow. Even in a good soil we will find bacteria which thrive in anoxic conditions, but in balance with other microorganisms so without causing any adverse effects. However, if there is too much it can cause things like di-nitrogen monoxide, methane production – imbalance caused by poor soil and very anaerobic conditions.
If we look at the issue of soil improvement, if we want to boost the number of living organisms in our soil – to carry on the sheep analogy, we need to give them the nutrients they need and they will breed. So how to feed them? It’s about how we manage our soil to actually get the nutrients into the soil in the right way to allow biodiversity to flourish.
Improving the soil
One of the most important things with soil is to keep it covered – because all soil would naturally be covered in vegetation. Without our intervention, the plants would be taking nutrients from the soil up through their roots, and then when they died the nutrients could return to the soil, taken down by the earthworms, bacteria, fungi and so on – this cycle creates the humus. You don’t want a bare soil – you want a soil that’s alive. Previously we used to plough in the autumn for a winter fallow, and the reason for doing that was to get rid of weeds, but we now know that this is damaging for good soil health. So now, between crops we will tend to put in clover lays or cover crops like Phacelia, which grows very fast and is great for pollinators, which can both cover the field, pull in nutrients, and attract insects.
Another of the big problems with soil health can be our monocultural cropping practices, which is why we have introduced a rotation system. On the farm, alongside our chicory which is for sale, on the fields that we’re resting we grow a deep-rooting chicory (grazing chicory) which will grow for 2-3 years mixed with mixed clovers and grasses to create a diverse range of plants to develop the soil. The really deep roots of the chicory is actually dragging up nutrients like phosphates and potassium from much deeper in the soil as the rhegolith beneath slowly erodes. We also use different types of catch-cover – either some of the smaller-seeded varieties which will produce a very quick growing crops to cover the surface, or maybe a larger-seeded one which will produce a bigger plant – perhaps in areas where light levels are lower. So we will plant something like a bean plant in tne autumn in this area to circulate the nutrients and keep this cycle going. So we will have a Kale crop in a field for two years, cycled with a green manure crop for two to three years. The bacteria that live on the clover roots (Rhizobia) actually make fertiliser for you that we can make in a factory at hign pressure and temperature, generating loads of CO2 – simply taking the nitrogen from the air and turning it into nitrates and ammonia. So that’s my routine to keep the soil healthy and keep those worm counts up. Despite the weather we’ve had recently, I’ve noticed real benefits in terms of cropping on the soils we’ve improved like this. I’m not getting as much run-off and the whole thing is working much better,
Locking up carbon in the soil
The reason for all of this is to increase levels of biological activity in the soil. So then you start to get a level of carbon capture in the soil – you’re making more humus which is storing carbon in the soil rather than it being in the atmosphere adding to greenhouse gas levels. A biologically active soil has more pore holes, better absorbing water which helps with flood preventions, and supporting a wider range of bacteria and fungi, mitigating the amount of methane production. And as well as this, my crops will grow better in this soil.
One of the newer techniques we’re starting to use is the Strip-till techniques. We’ll be planting the Kale in the strips so we don’t lose the benefits of the cover crop. Historically we would have ploughed the field – but when you’re doing this, you’re taking the soil and tipping it upside down, and this inverts the soil profile. It’s not natural – mostly you’d have a level service with the worms doing the work and the moles mixing it up a bit. So we take off the minimum area to plant our crop, that keeps the cycle going and without blitzing the soil. We also have a crimping machine which flattens the cover crop, and we can then cut the strips to plant. This is great as it also helps control the weeds, meaning we don’t need to use as many herbicides, as well as having benefits in soil chemistry and biology which probably mitigates the need to apply as much pesticide later on.
So – the future is in sustainablilty in the ecosystem. Maintaining food production whilst maintaining or increasing soil biota and the micro- to macro-fauna in and on our soil – the macro-fauna being rabbits, birds, even roe deer which we see knocking around on our land – we’re creating a much better environment for so many creatures, not just for my crops! The other benefit is in sequestering carbon in the soil. Because we’re growing that biota, we’re stuffing CO2 in the soil again, which has been denuded over recent years. This can help us in our aim to become carbon neutral over the years as well as making the farm and the landscape support a much wider range of wildlife.