The decision tree for estimating indirect N₂O emissions from agricultural soils outlines the steps Parties should follow (see Figure 4.8 in the IPCC Good Practice Guidance).

The main features of this decision tree are:

• If there is no nitrogen input to soils, then the Party should report “not occurring” (NO);
• If indirect emissions from agricultural soils is not a key category, or if the nitrogen source is not significant, emissions can be estimated using the default emission factors and partitioning fractions;
• If indirect emissions from agricultural soils is a key category, and the nitrogen source is significant, Parties should make efforts to collect country-specific activity data and rigorously documented partition fractions, and emission factors.