Soil is one of the most important resources on the planet and yet we've not been looking after it well of late. Here in the UK we lose around 2.2 million tonnes of topsoil each year due to wind and rain erosion. The UK government recently announced that some parts of the UK are thought to be just 30-40 years away from the eradication of soil fertility. (See Guardian, Defra and BBC links below).
One of the main reasons for this decline in fertility is tilling, ploughing, the application of pesticides and herbicides and large scale monoculture farming. Additionally, when the soil gets washed away, nitrogen and phosphorus based fertilisers end up in our rivers and lakes causing a process called eutrophication. This is basically when too many nutrients end up in a water system causing algal populations to boom, resulting in the depletion of oxygen in the water, harming aquatic plant and animal life.
Photograph taken by Dundee Satellite Receiving Station
The image above shows the coast of the South of England in February 2014. Horrifyingly, the brown colour around the coastline was the topsoil washed away after heavy rainfall. While soil is a renewable resource, it takes a very long time to build up. Rock minerals are one of the main components of soil and depending on the rock type it can take from 100-500 years to form just one inch of this vital resource. Looking after our soils is vital if we want to maintain biodiversity and ensure a food supply for future generations.
Permaculture design can help to rebuild the health of the soil by creating systems that mimic nature. All of the permaculture principles are relevant when it comes to building soil, however the most applicable principles are 'use and value diversity', 'integrate rather than segregate' and 'design from patterns to details' all while 'valuing this renewable resource and accepting feedback'.
The first two are key principles when it comes to the health of our soils, which depends on an unimaginable number of interactions between millions (if not trillions) of ecosystem components in order to stay healthy. Monoculture farming discourages these kind of interactions as whole areas are covered in single crops to make harvesting by machine easier, but this practice depletes nutrients and compacts the soil. The conventional farming response is to fertilise the soil with chemical fertiliser to keep the land producing but this comes with its own host of problems.
Photograph by Jon Bunting
The permaculture solution is to mimic the diversity found in nature and plant a mix of crops. These can still be planted in straight lines if desired (farmers and market gardeners might prefer to do this to make growing and harvesting easier) however planting a diverse range of crops in a diverse arrangement will increase edge and help maximise the beneficial connections between plants and animals. Using and valuing diversity can lower the risk of pests and disease (without using chemicals) and increase the quality of the soil. The risk of disease can be reduced using companion planting. Such plants can support each other in a number of different ways, such as fixing nitrogen, accumulating other nutrients, attracting pollinators or pest predators, or warding off diseases. This can help crops taste better, produce bigger yields, or protecting the crop from the elements. The more diversity you have the more beneficial connections you can create and when planned correctly the results can be exceptional.
The permaculture principle design from patterns to details is a particularly relevant one when it comes to soil health. Have you ever weeded a piece of earth to find that in a few weeks (or even sometimes days) it has been completely taken over again? Or when you walk in a forest do you ever notice that the forest floor is always covered in either leaf mulch or undergrowth? This is because the soil naturally wants to be covered, keeping soil bare is like having an open wound and preventing it from healing. Over time exposed earth degrades as moisture is lost and nutrients washed away. Exposed soil combined with heavy machinery is a recipe for disaster as compacted soil encourages even more run-off. This is a particularly serious situation where the main water source is ground water, as the rain finds it difficult to infiltrate the soil.
The permaculture solution is simple - keep soil covered! A technique called mulching can be used to protect it while suppressing weeds and adding nutrients at the same time. For example a mixture of straw, cardboard and compost can be laid down on beds. The cardboard keeps the light out and the straw and compost help lock in moisture and add nutrients to the soil. This is just one example as there are many different methods of mulching, it’s probably best to use whatever is easy to get hold of locally. Living mulches or green manures’ can also be used, these techniques involve keeping the soil covered with a living plant; a living mulch allows space for a crop to grow through whereas a green manure is turned into the soil when the new crop is ready to be planted in. 'Chopping and dropping' is another technique where weeds that haven’t yet gone to seed are simply chopped and left on top of the soil, functioning as a cover that adds nutrients and keeps in moisture.
Photograph of woodchip being used as a mulch - taken by Sarah Davenport
A farming technique that maintains, builds and regenerates soil using many of the methods mentioned above is slowly being adopted here in the UK. This technique is called agroecology and has been used in places such as Latin America for decades. A recent study on farms here in the UK called 'A Matter of Scale' shows how small farmers have managed to increase the health of their soil and obtain better yields by implementing design practices that mimic nature.
While this style of farming is slowly gaining momentum it's unfortunately not the way in which the majority of our food is farmed. Most supermarket food is grown on a large scale as large businesses find it easier to deal with fewer suppliers who can fulfil larger orders. It's easy become overwhelmed by all of the negative effects of our current lifestyle, however there are small and slow solutions that you can put into practice to help promote soil health. While growing our own food isn't possible for many of us, we can choose where we buy from, for example, small farms are less likely to use mechanised farming techniques and more likely to plant a diversity of crops. If you can access a local greengrocer, market, veg box or Community Supported Agriculture scheme, the supplier is more than likely to know where the produce has come from (if they haven't farmed it themselves), so you can get a better idea of how your food is being grown.
Farmers markets and greengrocers are often not a solution for everyone as they might not be accessible. If this is the case you could consider writing to your local supermarket to ask where the food is coming from and how it is farmed. The more people that ask these kinds of questions the better, as it will show that people do care about this and hopefully encourage shops to pay attention to where food is sourced and how it is farmed.
If you can, an even better way to save our soils (and energy) is to grow some of your own food. If you've even a small outdoor space with a well designed permaculture system you'll be surprised at how much you can grow. You could also create a personalised permaculture design around your food. For example, the use and value diversity principle could be applied in your shopping patterns. By diversifying the places you purchase food from you can get as much produce as possible from non-industrial farms while keeping within budget. Applying the principle produce no waste might make you think about using a composting system or even set up a community composting scheme, where food waste can be used to mulch and fertilise the soil. Through the application of small and slow solutions we can work towards designing a food system that feeds both us and our soils.