5-Crop-production-and-agricultural-soils/5.3-Greenhouse-gases/5.3.2-Indirect-N2O-emissions.md

@@ -18,11 +18,15 @@ Table 1  gives an overview of the methodologies applied. Since submission 2024
 
 Nitrogen inputs into soils are to some extent liable to runoff and leaching. The inputs into surface and ground waters give rise to indirect nitrous oxide emissions.
 
+The indirect N2O emissions as a result of leaching and surface runoff are calculated using a Tier 3 method since submission 2024. The methodology is based on the calculation of nitrogen surpluses, a proportion of which is washed out as nitrate or laterally displaced into receiving waters in a region-specific manner. The N surpluses are formed from the sum of the N inputs (from mineral fertilizers, manure (domestic and imported), crop residues, digestion residues, sewage sludge and composts) minus the N withdrawal in the harvest and minus the nitrogen produced when mineral and organic fertilizers are applied as NH3 -is emitted. Eysholdt et al. (2022) have modeled what proportion of the N excess at the NUTS-2 level is washed out or flows off the surface. This proportion is assumed to be constant over the entire time series. The methodology is described in detail in Eysholdt et al. (2022). 
+
+The indirect N2O emissions are calculated by multiplying the amount of N that is leached or flows off the surface with the N2O-N conversion factor 44/28, as well as the emission factor (0.011 kg N2O-N (kg N)-1, see IPCC (2019) ). Figure XX shows that the emissions resulting from the new method are significantly lower than with the previous Tier 1 method with constant FracLEACH.
+
 ## Frac<sub>LEACH</sub>
 
 <span dir="">Frac<sub>LEACH</sub> is defined as the relative fraction of N inputs into the soil that is lost via leaching and surface runoff (Frac<sub>LEACH</sub> = m<sub>leach</sub>/m<sub>soil</sub>; for m<sub>leach</sub> and m<sub>soil</sub>, see below.</span>
 
-<span dir="">In the German inventory, Frac<sub>LEACH</sub> is an input value. The IPCC default value Frac<sub>LEACH</sub> = 0.30 kg kg<sup>-1</sup> (</span>[<span dir="">IPCC (2006)</span>](/9-Literature#ipcc-intergovernmental-panel-on-climate-change-2006)<span dir="">-11.24, Table 11.3) is used.</span>
+The [IPCC (2006)](/9-Literature#ipcc-intergovernmental-panel-on-climate-change-2006) default value for FracLEACH used to calculate emissions until submission 2023 is no longer used, but an implied national FracLEACH value is subsequently calculated. 
 
 ## Activity data