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Can biochar help suppress GHGs?


April 7, 2011  by American Society of Agronomy

biocharpicsApril 7, 2011, Madison, WI
– Nitrous oxide is a potent greenhouse gas and a precursor to compounds that
contribute to the destruction of the ozone. Intensively managed, grazed
pastures are responsible for an increase in nitrous oxide emissions from
grazing animals’ excrement. Biochar is potentially a mitigation option for
reducing the world’s elevated carbon dioxide emissions, since the embodied
carbon can be sequestered in the soil. Biochar also has the potential to
beneficially alter soil nitrogen transformations.

April 7, 2011, Madison, WI
– Nitrous oxide is a potent greenhouse gas and a precursor to compounds that
contribute to the destruction of the ozone. Intensively managed, grazed
pastures are responsible for an increase in nitrous oxide emissions from
grazing animals’ excrement. Biochar is potentially a mitigation option for
reducing the world’s elevated carbon dioxide emissions, since the embodied
carbon can be sequestered in the soil. Biochar also has the potential to
beneficially alter soil nitrogen transformations.

Laboratory tests have
indicated that adding biochar to the soil could be used to suppress nitrous
oxide derived from livestock. Biochar has been used for soil carbon
sequestration in the same manner.

biocharpics  
   

Scientists at Lincoln
University
in New Zealand conducted an experiment over an 86-day spring/summer
period to determine the effect of incorporating biochar into the soil on nitrous
oxide emissions from the urine patches produced by cattle. Biochar was added to
the soil during pasture renovation and gas samples were taken on 33 different
occasions.

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The study was published in
the March/April 2011 issue of the Journal of Environmental Quality.

Addition of biochar to the
soil allowed for a 70 percent reduction in nitrous oxide fluxes over the course
of the study. Nitrogen contribution from livestock urine to the emitted nitrous
oxide decreased as well. The incorporation of biochar into the soil had no
detrimental effects on dry matter yield or total nitrogen content in the
pasture.

Arezoo Taghizadeh-Toosi,
who conducted the study, says that under the highest rate of biochar, ammonia
formation and its subsequent adsorption onto or into the biochar, reduced the
inorganic-nitrogen pool available for nitrifiers and thus nitrate
concentrations were reduced. Such effects would have diminished the substrate
available for microbial nitrous oxide production.

Research work is ongoing
and still required to determine seasonal effects, and the effects of repeated
urine deposition.

The full article is
available for no charge for 30 days following the date of this summary. View
the abstract at https://www.agronomy.org/publications/jeq/abstracts/40/2/468.

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