© Ricardo-AEA LtdRicardo-AEA in Confidence 1 Guidebook Update - Agriculture chapters – Anthropogenic nitric oxide J Webb on behalf of Ricardo-AEA and Aether and with input from Aarhus University and the EAGER group

© Ricardo-AEA LtdRicardo-AEA in Confidence 2 Emissions of NO have been shown to be highly episodic –with very large emissions of NO taking place ofter rainfall onto dry soil if followed by warm and dry weather. As a result the distribution of measured NO emissions is very skewed and difficult to predict for the compilation of annual inventories. In general, NO emission increases exponentially with soil temperature with Q10 values in the range of 2–3 Task 3.i. Restructuring and development of improved methods for the agricultural sector - nitric oxide

© Ricardo-AEA LtdRicardo-AEA in Confidence 3 Hudman et al. (2012) reported that pulses of NO emission that occur in response to meteorological events were not well represented by earlier models which were intended to estimate mean annual emisions of NO –their modelling study proposed that these pulses decay within 1-2 days compared with earlier estimates of pulse decay of 5-14 days –most strongly correlated with N availability, temperature and moisture content –the model of Hudman et al. (2012) related pulsed emissions to the length of the antecedent dry period Task 3.i. Restructuring and development of improved methods for the agricultural sector - nitric oxide

© Ricardo-AEA LtdRicardo-AEA in Confidence 4 The map of yearly average NO emissions presented by Hudman et al. (2012) indicates considerable variation among the UNECE and EU countries with Spain and Poland having greater emissions per ha than France or Italy Suggest this model may form the basis of a Tier 3 methodology And the output could be used to create Tier 1 default EFs for the UNECE countries Need to contact the authors to ask if we can use their output Task 3.i. Restructuring and development of improved methods for the agricultural sector - nitric oxide