Biochar mitigates greenhouse gas emissions from an acidic tea soil

Abstract

Acidic tea soil is an important greenhouse gas (GHG) emission source.Few studies have been done to investigate the impact of alkaline biochar addition on acidicsoil GHG emissions. We carried out a 40-day aerobic incubation experiment to investigate the alkaline biochar amendment on carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O) emissions from an acidic tea soil under N application. Soil samples were collected in the 0-15 cm layers from a tea orchard of Purple Mountain in Nanjing, Jiangsu Province, China. The results showed that biochar amendment significantly increased soil pH, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and the ratio of DOC/TDN at the end of incubation. N fertilization increased all three GHG emissions. In contrast, biochar amendment significantly decreased soil CO2 and N2 O emissions by 7.2-9.3% and 36.3-44.2%, respectively. Although the interaction of biochar and N fertilizer on soil CO2 and CH4 emissions were not obvious, N2 O emissions were significantly affected by their interaction. Consistent with CO2 and N2 O emissions, the net GWP was significantly decreased by biochar addition. Overall, the present study suggests that biochar amendment could be used as an effective management mitigating soil GHG emissions and the net GWP from the acidic tea field soil.