Greenhouse gas emissions from intensive pasture on ferrosol in Northern NSW, Australia: Impact of biochar amendment

摘要

An intensive field campaign was performed from April to June 2009 to assess the effect of biochar amendment on the emission of soil-borne GHGs from a sub-tropical pasture on acidic ferrosol. Over the whole measurement period high emissions of N_2O andhigh fluxes of CO_2 could be observed, whereas a net uptake of CH_4 was measured. Only small differences in the fluxes of N_2O and CH4 from the biochar amended plots (35.33 ± 4.83 mug N_2O-N/m~2/h, -6.76 ± 0.20 ug CH4 -C/m~2/h) vs. the control plots (31.08 ± 3.50 mug N_2O-N/m~2/h, -7.30 ± 0.19 ug CHU-C/m~2/h) could be observed, while there was no significant difference in the fluxes of CO_2. However, it could be observed that N_2O emissions were significantly lower from the biochar amended plots during periods with low emission rates (< 50 mug N_2O-N/m~2/h). Only during an extremely high emission event following heavy rainfall N_2O emissions from the biochar amended plots were higher than from the control plots. Our results demonstrate that pastures on ferrosols in Northern NSW are a significant source of GHG and that the amendment of biochar can alter those emissions. However, more field and laboratory incubation studies covering prolonged observation periods are needed to clarify the impact ofbiochar amendment on soil microbial processes and the emission of soil-borne GHGs.