Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/2010
Publication Date: 6/30/2010
Citation: Spokas, K.A. 2010. Production of Ethylene Following Soil Biochar Additions [abstract]. 2010 U.S. Biochar Initiative Conference. http://www.biorenew.iastate.edu/events/biochar2010/conference-agenda/agenda-overview/breakout-session-4/agriculture-forestry-soil-science-and-environment.html. On-line.
Technical Abstract: Overall, the initial hypotheses behind biochar’s impact on the soil microbial and plant systems have principally been focused on the interaction of the biochar with the soil structure, providing additional microbial habitat, improving water retention and infiltration, improving nutrient availability, buffering or altering the pH of the soil, chemical species sorption, as well as direct fertilization potential of the biochar itself. In addition to these factors, recent observations in laboratory soil + biochar incubations have revealed another potential hypothesis: Ethylene. Ethylene production has been observed from biochar alone (no inoculums) and biochar + soil incubations providing a tantalizing potential factor which could greatly influence both plant and root responses as well as soil microbial responses following biochar additions. From laboratory data, the production of ethylene is not constant and not all biochars produce ethylene at equivalent rates. The range of production rates have been observed between 0.5 and 20 ng C2H4/ g_soil/day. The important note is that all biochar materials tested (28 different biochars produced from various biomass sources and conditions) when mixed with soil have stimulated ethylene production. On the other hand, activated charcoals (coconut) have not caused observable ethylene production to date. Furthermore, ethylene can act as a nitrification inhibitor. This factor partially could explain the decreased nitrous oxide production observed after biochar additions. Nitrification inhibition also could explain the decreased nitrate formation and increased ammonium concentrations observed in soil + biochar incubations. This ethylene stimulation impact does appear to diminish with time from biochar production. However, this time factor is still being investigated. The exact cause of this formation is not fully understood. Nevertheless, these observations provide another potential mechanism behind biochar’s impact on both soil and plant systems.