Canadian greenhouse gas mitigation options in agriculture

In 1991, on farm management practices contributed 57.6 Tg CO2 equivalent in greenhouse gas emissions, that is, about 10% of the anthropogenic GHG emis sions in Canada. Approximately 11% of these emissions were in the form of C O2, 36% in the form of CH4 and 53% in the form of N2O. The CO2 emissions we re from soils; CH4 emissions were from enteric fermentation and manure, and N2O emissions were primarily a function of cropping practices and manure m anagement. With the emissions from all other agricultural practices include d, such as the emissions from fossil fuels used for transportation, manufac turing, food processing etc., the agricultural sector's contributions were about 15% of Canada's emissions. In this publication, several options are e xamined as to their potential for reducing greenhouse gas emissions. These involve soil and crop management, soil nutrient management, improved feedin g strategies, and carbon storage in industrial by-products. The Canadian Ec onomic Emissions Model for Agriculture (CEEMA) was used to predict the gree nhouse gas emissions for the year 2010, as well as the impact of mitigation options on greenhouse gas emissions from the agricultural sector. This mod el incorporates the Canadian Regional Agricultural sub-Model (CRAM), which predicts the activities related to agriculture in Canada up to 2010, as wel l as a Greenhouse Gas Emissions sub-Model (GGEM), which estimates the green house gas emissions associated with the various agricultural activities. Th e greenhouse gas emissions from all agricultural sources were 90.5 Tg CO2 e quivalent in 1991. Estimates based on CEEMA for the year 2010 indicate emis sions are expected to be 98.0 Tg CO2 equivalent under a business as usual s cenario, which assumes that the present trends in management practices will continue. The agricultural sector will then need to reduce its emissions b y about 12.9 Tg CO2 equivalent below 2010 forecasted emissions, if it is to attain its part of the Canadian government commitment made in Kyoto. Techn ologies focusing on increasing the soil carbon sink, reducing greenhouse ga s emissions and improving the overall farming efficiency, need to be refine d and developed as best management practices. The soils carbon sink can be increased through reduced tillage, reduced summer fallowing, increased use of grasslands and forage crops, etc. Key areas for the possible reduction o f greenhouse gas emissions are improved soil nutrient management, improved manure storage and handling, better livestock grazing and feeding strategie s, etc. The overall impact of these options is dependent on the adoption ra te. Agriculture's greenhouse gas reduction commitment could probably be met if soils are recognized as a carbon sink under the Kyoto Accord and if a w ide range of management practices are adopted on a large scale. None of the se options can currently be recommended as measures because their socio-eco nomic aspects have not been fully evaluated and there are still too many un certainties in the emission estimates.