What is Biochar
Biochar can be defined simply as char (charcoal) used for agricultural purposes. It can be produced from any type of biomass, including agricultural and forestry waste streams and manure. Biochar is manufactured by heating the biomass feedstock in an oxygen deprived environment, a process which is called "pyrolysis". Syngas, a flammable combination of hydrogen, carbon monoxide and methane, and excess heat are byproducts of the pyrolysis process. Once the reaction is started, it is largely self-sustaining, requiring no additional input of energy.
When biochar is created from biomass, approximately 50% of the carbon that the plants absorbed as CO2 from the atmosphere is "fixed" in the charcoal. As a material, the carbon in charcoal is largely inert, showing a relative lack of reactivity both chemically and biologically, and so it is strongly resistant to decomposition. Hence, biochar effectively recycles carbon from the atmosphere back to the soil in form that is at least an order of magnitude more stable than the organic material it was created from.
Of the many organic and inorganic substances that contain carbon atoms, only diamonds could potentially provide a more permanent carbon store than charcoal. Hence, biochar offers us a golden opportunity to remove excess CO2 from the atmosphere and sequester it in a virtually permanent and environmentally beneficial way.
Effect of Biochar on Soil Fertility
Below are a series of photos illustrating the effect of biochar on soil fertility. A vast majority of biochar trials to date show positive results such as these. They were taken during the International Biochar Initiative Conference held in Terrigal, Australia from April 29 to May 2, 2007.
The test plots shown in the photographs compare the following after 10 weeks:
1) Plain soil
2) Soil + NPK (Nitrogen, Phosphorous, and Potassium fertilizer)
3) Soil + Biochar
4) Soil + NPK + Biochar
Biochar with NPK fertilizer compared to plain soil.
Biochar with NPK fertilizer compared to NPK fertilizer alone. The capacity of biochar to help plants absorb nutrients is clearly evident in this photo.
Biochar without fertilizer compared with plain soil. Again, the ability of biochar to help plants absorb whatever nutrients are available in soil is evident in this photo.
Biochar only compared with NPK fertilizer only. This photo demonstrates that biochar may provide a means produce comparable results to conventional agriculture practice in organic farming or with reduced NPK usage.
Scientific Research on Biochar
Biochar has been the focus of a significant body of scientific research to date, and the number and scope of research projects is rapidly expanding. There are several resources currently available on the Internet related to scientific papers and research which are listed below.
International Biochar Initiative Bibliography
The International Biochar Initiative maintains a comprehensive listing of most scientific papers related to biochar. Go
Johannes Lehmann
Johannes Lehmann, an associate professor of Cornell University's Department of Crop and Soil Sciences, is one of the principal researchers working on biochar. Listed on his website are the biochar-related publications he has contributed to. Go