What is Biochar?

Today I am reading the September 2013 issue of Crops, Soils, Agronomy News. The cover article is about biochar.  From time to time I have read a bit about the miraculous properties of biochar, but I never even quite understood what it is.  The article says that biochar is made by slowly burning organic materials.  It could be made from anything living.  The material is usually heated to between 400 and 700 degrees Fahrenheit.  The product of that combustion is a charcoal type substance that sometime has been used as a soil amendment.  It can increase water holding capacity, and cation exchange capacity of soils.  It can grab on to minerals for slow release.  I am not sure what conditions might be needed to make biochar economical to produce for its own sake, but sometimes biochar is a product left over from extracting energy from biomass products.  In that context, it would make sense to land apply it for soil improvement. It looks like biochar is more resistant to decomposition than compost so it likely will retain positive properties for a longer time.

Mother Earth News talks about making biochar from hard to compost materials such as wood chips.  This Mother Earth News article includes  a lot of practical information on biochar.  They agree with CSA news that there is likely not much available mineral in biochar, but it appears to improve soil tilth.  I would say that if someone offers you a biochar product at low or no cost, take it.  Cover crops, no-till, and manure utilization may be a more rapid way for midwesterners to make some of the same improvements attributed to biochar. 

Click here to read the CSA News  cover article is about biochar.