Bio Char from the Junk Mail soil special 2014

Bio Char

There has been a great deal of excitement generated about biochar, which I date back to when James Lovelock, (of Gaia theory), stated and I paraphrase, that the greatest hope to avoid runaway climate change was to make loads of charcoal and bury it. This of course resulted in quite a reaction to say the least and as ever people divided into entrenched camps to argue it out.

In case you don’t know, BioChar is not a new invention. When the conquistadors were travelling up the Amazon in the mid 16^th century they found a civilisation lining the banks of the Amazon for mile after mile and these people had made garden with rich deep soils mixing composts with crushed charcoal which was called Terra Preta. These soils are mined to this day by garden centres in Brazil and sold. The best book I have found on the subject is called The Biochar Solution and is by Albert Bates, published by New Society.  Biochar is comprised of charcoal, which is pyrolised organic woody matter, i.e. heated in the absence of oxygen, so just like normal charcoal but this material is crushed and used in soils after being prepared in a variety of ways. Albert Bates is very clear that there a good and bad ways of making charcoal and the bad ways can be damaging and polluting and so obviously do not fit into the ethos of the whole reason to make it in the first place. Also that Biochar is not a panacea which will ‘save the planet’ but, that as a way of building, particularly degraded soils Biochar has a massively important part to play. Probably the most important factor to realise is that building soil health, and sequestering carbon in the soil through applications of composts and mulches and through no dig techniques, are also incredibly valuable.

Charcoal is an incredible substance, just a fragment the size of a rubber on the end of a pencil can have a surface area equivalent to a small house. It is a sponge like structure full of pores, on its own it does nothing to the soil but as Albert Bates says acts like a coral reef in the soil harbouring an astonishing amount of microbial life by vastly extending the surface area of the soil. Kilometres of fungal strands in a cubic centimetre, and all the other kingdoms of life present in the soil, all the beneficial bacteria, protozoa providing a richer food web in the soil and sequestering carbon indefinitely.