The difference between total chemical N fertilizer application estimated in this study and demand (MAFF 1986b, 1991b, 1997, 2002b, 2007) ranged from -10% to +5%. This difference would be due to the different recording periods (January to December for application and June to May for demand), stock on the market or farm, etc. Estimated N2O emissions in each year are shown in Fig. 40.2, together with CO2 equivalents (upper line graph). The estimations are lower than reported by GIO (2007), although the difference was less than 10%. The similarity of these independently estimated results demonstrates the validity of our estimations; however, the uncertainties and differences in the basic concept of the N framework which caused the differences are discussed later.
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