|THOMAZINI, ANDRES - Federal University - Brazil|
Submitted to: Agriculture, Ecosystems and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2015
Publication Date: 4/20/2015
Publication URL: http://handle.nal.usda.gov/10113/61039
Citation: Thomazini, A., Spokas, K.A., Hall, K.E., Ippolito, J.A., Lentz, R.D., Novak, J.M. 2015. GHG impacts of biochar: Predictability for the same biochar. Agriculture, Ecosystems and Environment. 207:183-191.
Interpretive Summary: Biochar has been gaining attention, both in the public and scientific circles, as a means to combat climate change and at the same time improve soil fertility. However, there has been very little attention focused on the impact of biochar additions have on the variability of the alteration in GHG response across different soils. In this research, we looked at the effect of a biochar addition across nine different US agricultural and forest soils. Our results support the conclusion that both chemical and biological mechanisms are responsible for the GHG response. This was supported by the correlations observed with microbial biomass and potassium, suggesting a cation exchange related mechanism. The properties of both the biochar and soil influenced the observed responses. Thereby, this research highlights that biochar amendments need to be selected based on the desired mode of action and not all biochar types are suitable for addition to all soil systems. Additional research is needed to fully characterize the surface chemistry responsible for these effects. These results are significant to farmers and policy makers and will assist scientists and engineers in developing improved biochars based on properties to minimize agrochemical transport and improve soil carbon management.
Technical Abstract: One potential strategy to abate increasing atmospheric carbon dioxide (CO2) levels is to sequester CO2 as biochar, a more stable form of carbon created through the pyrolysis of various biomass materials. Biochar may be applied to soils, but has resulted in variable impacts on net soil greenhouse gas (GHG) emissions, with results spanning from suppression to stimulation. This laboratory incubation study examined the impacts of a hardwood biochar (fast pyrolysis at 550 oC) to elucidate driving variables affecting previously observed carbon dioxide (CO2) fluctuations as well as nitrous oxide (N2O), and methane (CH4) production impacts across ten different US soils with and without biochar (10% w/w). Biochar application significantly impacted CO2 (P=0.038) and N2O (P=0.027) production following amendment across all soils, but there were no differences observed in CH4 production/oxidation rates (P=0.897). The observed production rate alterations following biochar additions across all soils were significantly correlated to the initial GHG production activity in the control soil, suggesting a more universal response across various soils to the same biochar than has been previously hypothesized. After correcting for the amount of CO2 released from the biochar itself [12 µg C (0.5 gBC)-1 d-1], there was no significant alteration in the actual soil CO2 mineralization rate for any soil. On the other hand, there was an average suppression of 63% in the N2O production across all soils following biochar addition, which was correlated to the initial N2O activity. For this particular biochar, there are predictable impacts on the GHG production potential across various soils despite differences in soil chemistry, texture, and microbial communities.