291-9 Biochar Addition Rate Mediates Greenhouse Gas Flux of Four Soils - the Importance of Long-Term Data.



Tuesday, October 18, 2011: 3:20 PM
Henry Gonzalez Convention Center, Room 210B, Concourse Level

Catherine Stewart, USDA, ARS Soil Plant Nutrient Research Unit, Fort Collins, CO, Jiyong Zheng, State Key Laboratory of Soil Erosion and Dyland Farming on the Loess Plateau, Northwest A & F University, Yangling, China and M. Francesca Cotrufo, Colorado State University, Fort Collins, CO
Biochar addition to soil has been proposed as a method of soil C sequestration with added benefits of improving nutrient retention and decreasing greenhouse gas flux. However, research to date has documented a net positive, neutral, or negative effect on CO2, N2O, and CH4 emissions depending on the biochar feedstock, pyrolysis temperature, as well as soil type.  Our objective was to determine the effect of biochar addition rates (0, 1, 5, 10, and 20% by weight) on trace gas emission from four soils varying from a clay to a sand on during a long-term incubation. To trace CO2 source, we added C3 biochar (pyrolyzed at 550C) to C4 soils and measured CO2, N2O, and CH4 over a 1.5 yr incubation.  Biochar addition initially suppressed CO2, but after 3-4 months, biochar-derived CO2 increased in accordance with biochar addition rate. In all soils, N2O emissions were suppressed, although the response to addition rate varied from 20% to 94% reduction depending on soil type.
See more from this Division: S11 Soils & Environmental Quality
See more from this Session: Environmental Functions of Biochar: I