Agricultural practices as natural climate solutions in the Canadian Prairies.

Management practices focused on environmental outcomes in agriculture can increase soil organic carbon (SOC) and reduce greenhouse gas (GHG) emissions, complementing farm production practices that provide food and a wide variety of other social-ecological services. However, evidence of the efficacy of such practices for mitigation of climate change is inconsistent and no one recent study brings it all together for the Canadian Prairies, a globally important agricultural region and ecosystem. We reviewed 140 field-based studies (published 2000-2024) examining nine practices: shelterbelts, perennial cover, organic soil amendments, reduced tillage, cover crops, diversified crop rotations, rotational grazing, nitrogen (N) management, and wetland rewetting. Using meta-analysis techniques, we extracted mean and standard deviation of variables related to SOC and GHG from tables, figures, and text. Almost all practices showed beneficial effects on SOC or GHG emissions but with high variability, indicating where further research can fill knowledge gaps, such as rotational grazing and wetland rewetting. Significant SOC effects were apparent (5-10%, 4-17 Mg C/ha) for practices focused on perennial cover and reduced tillage. Nitrous oxide emission reductions (19-88%, 85-941 kg CO2e/ha) were significant for shelterbelts, perennial cover, organic soil amendments, N management, and diversified crop rotations. Our findings can support evidence-based prioritization of farm-level practices and strategies for climate change mitigation in semi-arid agricultural regions.