Local gardeners have been taking part in a national biochar experiment managed by Garden Organic and Coventry University. Biochar is produced by ‘thermal degradation of organic material in the absence of air (pyrolysis)’, but fortunately for the gardeners, the charcoal-like soil additive was delivered in sturdy brown bags!
Biochar can remain in the soil for thousands of years, so is a form of carbon sequestration. The big question is: does it also impact on crop yields? Gardeners made matching 1-metre square plots, and managed them identically in all ways except the addition of the biochar to one plot.
A few of the experiments went astray – or proved very tempting to the local slugs – but first indications from Coventry University’s analysis of the national results suggest that there was probably a small positive impact on yields. There are plans to run the experiment again next year. Contact firstname.lastname@example.org if you would like to be kept informed.