ARS | Publication request: Impacts of biochar additions on soil microbial processes and nitrogen cycling

Submitted to: Humic Science and Technology Conference
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2011
Publication Date: September 9, 2011
Citation: Spokas, K.A. 2011. Impacts of biochar additions on soil microbial processes and nitrogen cycling. Humic Science and Technology Conference. Presentation 1.

Technical Abstract: A potential abatement strategy to curb increasing atmospheric levels of carbon dioxide (CO2) is to sequester atmospheric CO2 into more stable forms. Biochar is the solid by-product from the pyrolysis of biomass which is intentionally produced for the purposes of atmospheric carbon sequestration. The application of biochar to various soils has resulted in a variety of crop and soil responses: including positive, negative and no response. However, the mechanisms behind the “biochar effect” have not been fully elucidated. In the present work, we have determined the sorbed volatile organic fingerprints for various parent materials and pyrolysis conditions, using headspace thermal desorption. In general, higher pyrolysis temperatures lead to lower amounts of lighter molecular weight organic components being sorbed to the biochar. However, this is not a universal conclusion and the sorbed organic compounds are highly variable across different pyrolysis units, despite similarity in production temperature, feedstock and residency times. The total amount of sorbed organics is typically within the ppm range. Higher pyrolysis temperatures typically favor higher molecular weight semi- and non-volatile organics (e.g. polyaromtic hydrocarbons) retention on the biochar. These sorbed volatiles could provide additional insight into the soil and plant system responses observed from biochar additions, particularly due to the lack of consistent response to biochar amendments. This presentation will summarize a brief history of biochar and provide insight into potential roles of biochar in the soil system.