Although I am a plant scientist, I rarely get to work with proper soil (my Arabidopsis seedlings are all grown on an artificial medium called vermiculite which looks a bit like muesli). But given that soil is so critical for growing crops - and thus underpins the base of all our food chains - it is something we should all take make seriously. To address my general ignorance, last week I went along to 'Building UK Soils - Political and Practical Opportunities', a seminar organised by the Grantham Centre for Sustainable Futures.
Both of the invited speakers worked for the Soil Association, a charity formed in 1946 with the aim of 'demonstrating and promoting the link between healthy soils, healthy plants and healthy people'. You may have come across their logo during your weekly shop as they operate the British Organic certification scheme. Head of Horticulture Ben Raskin immediately debunked the popular misconception that soil is dull, inert and uninteresting by sharing some impressive statistics. For instance, it is thought that there are more organisms in a teaspoon of soil than there are people on the planet - including Rotifers, tardigrades, mites, nematodes, Protozoa and around 4,000 million bacteria. So it's not just about worms and spiders! With all this diversity, it is not surprising that soils can vary considerably between regions, especially as they are also shaped by environmental factors such as pH, climate and water availability. All this, of course, has a direct impact on the crops growing on the surface. For example, the availability of essential nutrients for plant growth is highly sensitive to the pH of the soil. Over recent years however, it seems that farmers are attaching less and less importance to basic 'soil husbandry' and are being increasingly 'disconnected' from the landscape. As agriculture becomes more industrialised and mechanised, farmers spend very little time actually handling the earth their livelihoods depend on. "Everything we do has an impact and that has to be considered when building a long term system" said Ben. But this is rarely considered - for instance, when farmers spray their ploughs with fungicides, this ultimately kills many of the beneficial fungi strains within the soil. According to Ben, these problems are aggravated by the trend towards short tenancy arrangements - a far cry from the days when farms were handed down between the generations. As a result, farmers are focused on "getting their crops in the ground, harvesting them and then getting out" - with little thought for the state they leave the soil in for the next occupant.
But there are some very creative ideas out there to help reverse this damage, including agroforestry, where introducing trees onto farmland can protect the soil and improve fertility. Another strategy, particularly for dairy farms, is 'mob grazing'. In this practice, rather than letting farm animals wander freely over the field, the animals are kept in fenced off blocks to completely graze one area before being moved to another. According to Ben "This is more similar to when herbivores roamed the land in ancient times, grazing one area before moving on and not coming back". However, more work is needed to translate these ideas into common practice. "University researchers are doing wonderful projects but they don't get anywhere - we need farmers and researchers to work together" Ben said. As part of a three year programme, The Soil Association, in partnership with the Duchy Future Farming Project, is funding a range of on-farm projects to investigate the potential benefits of altered practices. Meanwhile, 'Innovative Farming Clubs' are encouraging the agricultural community to communicate more about soil issues. "If people are sitting in their own silos, doing their own thing, they can miss what's going on" Ben said, before giving the example of a farmer who was inspired by a football manager to install vertical drains on his farm. Hopefully, with more of this 'joined- up thinking', these innovations can begin to be disseminated on a wider scale.
Ben Raskin and Louise Payton from the Soil Association
It's one thing to get farmers excited about soil but what about the Government? Enter Louise Payton, Policy Officer at The Soil Association. She began by introducing the rather frightening situation regarding global soils: a quarter of all soil in the world is severely degraded with 10 million hectares ( an area the size of England and Wales combined) being abandoned every year. According to some estimates, we may only have 60 years of viable topsoil left to grow crops. Perhaps most dramatic was her slide showing a satellite photograph of the UK taken after the terrible floods of 2013-14. The waters hugging the coastline had literally been stained brown by the soil which had been washed off from inland. It seems that Governments are slowly waking up to the soil crisis, with 2015 being designated the 'International Year of Soil'. But unfortunately, this hasn't really amounted to much so far. In the UK, the Government's soil policies are quite vague, along the lines that farmers should maintain soil organic matter and take steps to minimise soil erosion - particularly by planting cover crops instead of leaving the earth bare. But as Louise said, "The problem with these regulations is that when you look at the details, they don't really mean anything". For instance, maize stubble could be interpreted as a 'cover crop' even though this is pretty useless at preventing erosion. In addition, there is a convenient loophole which allows famers to avoid taking the effort to protect their soils 'if it would affect their business'. The EU has Directives for air, habitats and water - so why not soil?! As Louise explained, air, water and wildlife are seen as entities for the public good that are not owned by anybody. Land in the other hand, is most definitely owned by somebody and so governments are hesitant to impose legislation, feeling it is outside their bounds. The Soil Association is campaigning to move soils further up the government agenda although success has been limited so far: the last time they sent a letter to the Secretary of State, apparently the reply went along the lines of "Sorry, we're too busy right now, and soils aren't that interesting!"
But perhaps things are about to change. Recently, The UK Climate Change Committee released a report describing UK soils as having 'red status', declaring that "the agricultural a community has been blind to what has been happening'. Meanwhile the Soil Association have focused their efforts on getting the Government to agree to a target of improving soil organic matter (SOM) across the country by 20% by the year 2020. This would have multiple benefits for soil health, beyond improving fertility and the microbial communities of the soil. For one thing, SOM helps to capture carbon, thus mitigating against climate change. In addition, "it acts a but like a sponge" - capturing water during drought and draining it away in times of flood. Another campaign is for greater research into how pesticides affect soil health. Louise presented the results of a study which found that, over the course of one year, 22 active chemicals were used on a single field of oilseed rape alone. The effects that these chemical cocktails have on soil communities is virtually unknown. Hence, as a first step, the Soil Association are commissioning studies on the most common insecticides: glyphosphate sand neonicotinoids. If I wasn't already studying parasitic weeds, I might be tempted to retrain as a soil scientist! But in the meantime, I will certainly have a greater respect for soils and will keep my eye out for campaigns to have their role recognised by our politicians also.
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