Biochar is something of a buzzword at the moment. Documentaries like Kiss the Ground and The Need to Grow have highlighted the plight of our soil and its importance to our global food security into the mainstream media. The United Nations Framework Convention on Climate Change (UNFCC) has identified the use of biochar as an important element in achieving a net zero carbon footprint by 2050 and local initiatives like Circle Carbon here in Mallorca are leading the way producing and educating us all on the benefits of soil regeneration.
Recently, I went on a tour of their farm and saw for myself greenhouses full of tropical fruit, vegetables, herbs and other superfoods like Moringa being grown using the biochar they produce. The size of the papayas was like something you´d expect to see in the jungle. To demonstrate the difference a nutrient rich soil can make they planted several papaya tree´s from seed, some using biochar and some in ´regular´ compost – the size of the trees, fruit and the amount of fruit produced using biochar were clearly better. In fact, all of the vegetables looked abundant and healthy with no holes in the leaves, no wilting, no discolouration – they use zero pest control or chemical fertilisers and only minimal water, just biochar mixed with nutrient rich compost.
So what exactly is it? Biochar is a type of charcoal produced through a process called ´pyrolysis´. This means burning organic matter (biomass) fast and hot with very little oxygen. Restricting the oxygen intake leaves you with charcoal in it´s purest state possible. If you´re wondering what makes biochar different from your regular BBQ charcoal then it´s all to do with temperature – BBQ coals are produced at around 400 degrees celsius but biochar charcoal is created when you start to burn your biomass at around 400 degrees heading up to 800 degree´s at peak temperature.
At Circle Carbon they use tree cuttings from mainly Olive, Almond, Carob and Pine, all of which are sourced locally from farmers. Whatever isn´t suitable for the kiln goes into the compost heap which is the other part of the equation – the biochar is mixed with other organic mineral and nutrients (compost) which itself is then left to compost for up to a year, creating the ideal environment for the micro-organisms to get to work on producing a nutrient rich soil. It´s this mixture of biochar and compost they call Terra Llum which they use to grow their vegetables and other produce.
The biochar is made in a kiln called a ´kon-tiki´ which looks like a large steel drum. It has no air inlet underneath and the biomass is layered in a particular way. Once a layer of coals has been established, more biomass is placed on top and the flames produced work like a cap, sealing in the heat underneath whilst also burning off the volatile organic compounds (gases). This heat and lack of oxygen enables the kiln to break down the biomass and open up it´s pores and cavities while capturing the carbon contained.
It´s the sequestering of this historical carbon that´s so important. In 2018, the Intergovernmental Panel on Climate Change (IPCC) identified four ways to help us draw-down the accumulated Co2 in the atmosphere to under 350 parts per million (we are currently over 420 p.p.m). The methods they have identified are:
- Stopping de-forestation
- Re-planting trees (afforestation and reforestation)
- Changes to agricultural farming (crop rotations, no tilling of soil)
One of the most promising things about biochar is that anyone can make it in their garden using an oil drum or digging a pit in the ground. Search online and you´ll find lots of videos of people making it at home to use in their gardens. However, I think it´s fair to say most of us don´t have the space or time to do it ourselves and it is a labour intensive process – it´s much easier to go and buy a sack from Circle Carbon! They grind their biochar down to a powder to maximise the surface area – a little goes a long way as well, you need about two kilo´s per square metre.
If you are growing your own vegetables then investing in some biochar is well worth it especially when it is estimated that the soil here in the Mediterranean contains less than 1% of organic matter – that´s one step away from pre-desertification. Centuries of rotavating and tilling the soil have stripped it of its nutrients by exposing the micro-organisms in the deeper layers of the soil to the heat, wind, rain and other elements. It´s all well and good eating organically (and undoubtedly better than the offerings at most supermarkets) but even if a vegetable is grown organically it wont be rich in the nutrients we need if it has been grown in depleted soil.
As recognition of biochar and its importance grows, more research and papers are being written at an academic level than ever. Current technologies and techniques will no doubt be improved as our understanding deepens. What is for certain, is that for our children and the generations to come food supply and security is going to be a major issue if we continue down the path already trodden. The conflict between utilising land for food production and industry versus preserving land is already a real one, it will only deepen unless more progressive and sustainable options are adopted.
As with all things, education is key. Seek out biochar initiatives in your area and if you´d like to do some reading on the topic here are our book recommendations:
- Gardening with Biochar by Jeff Cox
- Dirt, The Erosion of Civilizations by David R. Montgomery
- Burn, Using Fire to Cool the Earth by Albert Bates and Kathleen Draper
- Sacred Soil by Robert Tindall, Frederique Apfel-Marglin and David Shearer
- Kiss the Ground by Josh Tickell (now also a documentary on Netflix)
- The Need to Grow – also a documentary and a must watch for all the family.