Burning and cultivation effects on greenhouse gas emissions and nutrients in wetland soils from Saskatchewan, Canada

Wetland fringe areas in prairie agricultural landscapes may be subjected to burning of vegetation in autumn followed by cultivation in spring. The objective of this study was to examine the greenhouse gas (CO2, N2O and CH4) emissions and plant nutrient (NO3, PO4 and SO4) supplies in wetland fringe soils as affected by simulated burning + cultivation, at field capacity and saturation moisture content. Using undisturbed soil cores collected from grassed wetland fringes at four sites in southern Saskatchewan, the impacts were examined over a 20-day period. The burning + cultivation treatment generally reduced CO2 emissions, tended to increase NO3-N availability, and had no consistent effect on N2O emissions, or PO4-P and SO4-S supply. Production of CH4 occurred only at one site, and only under saturated conditions. Compared to field capacity, saturation reduced CO2 emissions and NO3-N supply, tended to increase PO4-P availability, and had no consistent effect on N2O emissions and SO4-S. The CO2 emissions and SO4-S were greater for soil cores with higher organic matter and salinity, respectively. The N2O emissions were only occasionally related to soil NO3-N supply rate.