Energy based GHG emissions from Canadian agriculture.

Energy must be considered in the assessment of greenhouse gas (GHG) emissions from agriculture, even though, compared to methane and nitrous oxide emissions, it is a smaller source which is usually attributed to other sectors such as transportation and manufacturing. This communication summarises some analytical methods that have been developed to inventory energy based GHG emissions from Canadian agriculture. Farm energy survey data provided verification for these methods. Agricultural energy can be classified as either direct or indirect. Direct energy includes on-farm fossil fuel and electricity use, while indirect energy includes all the manufacturing of farm inputs. The main indirect energy uses are synthetic fertiliser supply and farm machinery production. Farm field work and crop drying account for most of the fossil fuel used on the farm. The energy budget for two typical Canadian farms estimated with the methods described here demonstrates the huge impact of regional and farm type differences on farm level GHG emissions. [ABSTRACT FROM AUTHOR]