Examining Mechanisms Behind Biochar's Nitrogen Impacts.

Biochar is the solid residual produced from the pyrolysis of biomass, which is focused on the utility of the residue as a vehicle for carbon sequestration.  In addition, laboratory and some field results have shown statistically significant impacts in the avaiability of soil nutrients and the production of some greenhouse gases, particularly N₂O, following biochar additions.  There have been several hypotheses into the potential mechanisms causing these effects.  The focus has been on improved CEC of the amedned soil.  However, recent laboratory studies involving soils and biochars from around the globe have provided additional insight into other potential mechanisms.  One of these is the importance of abiotic denitrification by carbon-iron complexes.  These results along with previous hypotheses provide a glimpse into the complicated interactions of soil-biochar chemistries and microbial associations.  This leads to the conclusion that multiple simultaneous processes are occurring and emphasize the fact that potentially different mechanisms are active in each unique soil-biochar mixture.