Characterizing Biochars prior to Addition to Soils

Hugh McLaughlin, PhD, PE, Alterna Biocarbon Inc. , January 2010

Biochar is a vague term that applies to a potentially broad class of charcoal materials intended for addition to soils. Many raw materials and conversion processes can lay claim to producing biochar, and the resulting biochars will have different characteristics. The purpose of this discussion is to formulate a simple scheme for characterizing biochars before addition to soils. Efforts will be made to discuss the logic behind the individual characteristics, in addition to the limitations of the individual assays.

The presentation and content here is consistent with the paper titled “All Biochars are Not Created Equal, and How to Tell Them Apart”, by McLaughlin, Anderson, Shields and Reed presented at the North America Biochar Conference in Boulder, August, 2009. (http://cees.colorado.edu/biochar_characterization.html). However, this discussion is new, in the sense that it attempts to simplify the logic and methodology in order to arrive at a characterization strategy that is widely accessible to many practitioners.

The general characterization scheme breaks the biochar into a small number of constituent parts, consisting of: Moisture, Ash, Mobile Matter and Resident Matter. Each constituent part can be further subdivided, as will be discussed. Initially, we will discuss the significance of each portion, how it is measured and what the measurement represents. Then we will discuss additional biochar consideration when added to soils.

For addition detail, download the attached pdf: Characterizing Biochars