Revisiting sampling duration to estimate N2O emission factors for manure application and cattle excreta deposition for the UK and Ireland. (15th November 2022)

• Record Type: Journal Article
• Authors: Vangeli, Sebastian; Cardenas, Laura M.; Posse, Gabriela; Chadwick, Dave R.; Krol, Dominika J.; Thorman, Rachel E.; Lanigan, Gary J.; Misselbrook, Tom H.
• Is Part Of: Journal of environmental management. Volume 322(2022)
• Publication Date: 2022-11-15
• Subjects: Greenhouse gasses -- Climate change -- Inventory -- Nitrogen cycle -- Grassland -- Agriculture; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.116037
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: According to the available guidelines, good practices for calculating nitrous oxide (N2 O) emission factors (EFs) for livestock excreta and manure application include that sampling duration should be of at least one year after the nitrogen (N) application or deposition. However, the available experimental data suggest that in many cases most emissions are concentrated in the first months following N application. Therefore resources could be better deployed by measuring more intensively during a shorter period. This study aimed to assess the contribution of the N2 O flux in the period directly after N application to the annual net emission. We used a database of 100 year-long plot experiments from different excreted-N sources (dung, urine, farmyard manure and slurry) used to derive EFs for the UK and Ireland. We explored different shorter potential measurement periods that could be used as proxies for cumulative annual emissions. The analysis showed that the majority of emissions occur in the first months after application, especially in experiments that i) had urine as the N source, ii) had spring N application, iii) were conducted on fine-textured soils, or iv) showed high annual emissions magnitude. Experiments that showed a smaller percentage of emissions in the first months also had a low magnitude of annual net emissions (below 370 gN2 O–N ha −1 year −1 ), so the impact of measuring during a shorter period would not greatly influence the calculated EF. Accurate EF estimations were obtained by measuring for at least 60 days for urine (underestimation: 7.1%), 120 days for dung and slurry (4.7 and 5.1%) and 180 days for FYM (1.4%). At least in temperate climates, these results are promising in terms of being able to estimate annual N2 O fluxes accurately by collecting data for less than 12 months, with significant resource-saving when conducting experiments towards developing country-specific EFs. Highlights: Sampling period to calculate country-specific N2 O emission factors was revised. We analyzed data from 100 year-long IPCC compliant manure and excreta experiments. A high proportion of annual emissions occurred in the months directly after N application. Accurate EFs were measured at 60–180 days, with significant resource saving.