ARS | Publication request: Greenhouse gas emission from soil amended with biochar made from hydrothermally carbonizing swine solids

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 18, 2009
Publication Date: March 21, 2010
Citation: Ro, K.S., Novak, J.M., Bae, S., Flora, J., Berge, N. 2010. Greenhouse gas emission from soil amended with biochar made from hydrothermally carbonizing swine solids [abstract]. American Chemical Society National Meeting, March 21-25, 2010, San Francisco, California.

Technical Abstract: Biochar made from hydrothermally carbonizing swine solids was mixed with a 50/50 mixture of Norfolk Ap and E horizon at a rate of 20 g/kg. During the incubation period of 54 days, greenhouse gas (CO2 and N2O) emission fluxes were calculated by nonlinearly regressing time-series headspace gas concentrations measured by a photoacoustic multi-gas analyzer. Throughout the incubation period, the control soils did not produce any significant CO2 nor N2O fluxes. Biochar-amended soil, however, emitted CO2 fluxes as high as 7.1 g CO2 m-2/d in the beginning of incubation. Based on 13C-NMR spectra of the biochar, we speculate that the high CO2 fluxes were attributable to aliphatic compounds in the biochar. The biochar-amended soil produced a small N2O flux of 0.13 mg N2O m-2/d only on day 20 (2 days after leaching test). Similarly on that day, control soils produced about 0.06 mg N2O m-2/d, suggesting that anaerobic condition may be the driving force for N2O emission. These N2O fluxes are about two orders of magnitude smaller than that measured from Australian unfertilized soils. Addition of swine solid biochar dramatically increased soil CO2 emission; however, N2O emission was not significantly affected.