Greenhouse Gas Emissions Following Tillage Reversal on a Black Chernozem and a Gray Luvisol in Alberta

Agricultural soils under long-term no till management have been well known to sequester atmospheric carbon in soil organic matter and to reduce emissions of greenhouse gases. Our study aimed at quantifying CO 2 and N2O emissions from Black Chernozems and Gray Luvisols managed under long-term (∼ 30 years) no till after tillage reversal. Our study revealed that both CO2 and N2O emissions were stimulated by tillage reversal. Comparative studies showed that the short-term rates of CO2 and N2O emissions after tillage reversal were higher than the historical rates of sequestration after the adoption of long term no till. Since the time scales for comparing the sequestration and emission rates were so different, these results are expected and reasonable. These results indicate that increased soil carbon storage resulting from changes in agricultural management practices is reversible and that the potential for carbon sequestration is dependent on the long-term trends of management practices.