POSSIBILITIES FOR FUTURE CARBON SEQUESTRATION IN CANADIAN AGRICULTUREIN RELATION TO LAND-USE CHANGES

Increasing carbon sequestration in agricultural soils in Canada is exa mined as a possible strategy in slowing or stopping the current increa se in atmospheric CO, concentrations. Estimates are provided on the am ount of carbon that could be sequestered in soils in various regions i n Canada by reducing summerfallow area, increased use of forage crops, improved erosion control, shifts from conventional to minimal and no- till, and more intensive use of fertilizers. The reduction of summerfa llow by more intensive agriculture would increase the continuous cropl and base by 8.1% in western Canada and 6.8% in all of Canada. Although increased organic carbon (OC) sequestration could be achieved in all agricultural regions, the greatest potential gains are in areas of Che rnozemic soils. The best management options include reduction of summe rfallow, conversion of fallow areas to hay or continuous cereals, fert ilization to ensure nutrient balance, and adoption of soil conservatio n measures. The adoption of these options could sequester about 50-75% of the total agricultural emissions of CO2 in Canada for the next 30 years. However, increased sequestration of atmospheric carbon in the s oil is possible for only a limited time. Increased efforts must be mad e to reduce emissions if long-term mitigation is to be achieved.