Crop rotation and tillage impact on carbon sequestration in Canadian prairie soils

Carbon sequestration was determined for different tillage systems in semiarid to sub-humid climates and coarse to fine-soil texture in Saskatchewan, Canada. Annually cropped rotations sequestered 27–430 kg C ha-1 per year more than crop rotations containing bare fallow. The potential for sequestering soil organic C (SOC) with crop rotations without bare fallow was greater in the sub-humid than in the drier climates. No-tillage (NT) sequestered 67–512 kg C ha-1 per year more than tilled systems. With elimination of both tillage and bare fallow, the SOC increase was approximately 300 kg C ha-1 per year in the semiarid climate regardless of soil texture, and approximately 800 kg C ha-1 per year in the sub-humid climate. Relative annual increase in SOC under no-till was approximately a linear function of clay content across locations. Fine-textured soils have a greater potential for gains in SOC under no-till in Canadian prairie region.