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Arable croplands are critical in the context of climate change, acting as both sources and potential sinks of greenhouse gases (GHG) in the form of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O). However, there is limited data on the carbon (C) balance and GHG budget (GHGB) from canola-wheat rotations in the northern Prairies of North America, an important agricultural region. We present micrometeorological GHG fluxes measured from January 2021 to April 2025 through two rotations of canola-wheat in Saskatchewan, Canada, to evaluate the interannual C dynamics and GHGB of the 4-year cropping sequence. Net ecosystem exchange (NEE) ranged from 87 to -239 g C m -2 , driven by variable meteorological conditions. Annual cumulative gross primary production (GPP) exceeded the cumulative ecosystem respiration ( R e ) in all years except 2021—the second driest year on record for this region. The GHGB values were between 60 and 156 CO 2 -eq m -2 yr -1 in the first 3 crop years, but were negative (i.e., GHG sink) in Year 4. Overall, this study presents the first multi-year, measurement-based assessment of canola-wheat rotations in the northern Prairies, showing that over a 4-year period, the cropping system was C neutral (net ecosystem carbon balance NECB = 2 ± 35 g C m -2 yr -1 ). The dataset provides the region-specific information needed to inform C policy and evaluate the agricultural sustainability of the northern Prairies. It also provides valuable information for canola and wheat crops, particularly the impact of harvest removals and N fertilizer application—practices that can be targeted for agricultural GHG emissions mitigation.
Ferland et al. (Sat,) studied this question.