Instituto de Clima y Agua, CIRN, CNIA INTA Castelar, 1686, Hurlingham, Buenos Aires, Argentina; Facultad de Agronomia, Cátedra de Manejo y Conservación de Suelos, Universidad de Buenos Aires, 1417, Buenos Aires, Argentina.
Sustainable Agriculture Sciences, Rothamsted Research, North Wyke, Okehampton, Devon, EX20 2SB, UK.
J Environ Manage. 2022 Nov 15;322:116037. doi: 10.1016/j.jenvman.2022.116037. Epub 2022 Aug 29.
According to the available guidelines, good practices for calculating nitrous oxide (NO) 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 NO 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 gNO-N ha year), 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 NO fluxes accurately by collecting data for less than 12 months, with significant resource-saving when conducting experiments towards developing country-specific EFs.
根据现有指南，计算家畜排泄物和粪肥应用中氧化亚氮（NO）排放因子（EF）的良好实践包括，采样持续时间应在氮（N）应用或沉积后至少一年。然而，现有实验数据表明，在许多情况下，大多数排放集中在 N 应用后的头几个月内。因此，通过在较短的时间内更密集地测量，可以更好地部署资源。本研究旨在评估 N 应用后直接时期的 NO 通量对年净排放的贡献。我们使用了来自不同排泄 N 源（粪便、尿液、厩肥和粪浆）的 100 个为期一年的田间实验数据库，用于推导英国和爱尔兰的 EF。我们探索了不同的潜在较短测量期，可以作为累积年排放量的代理。分析表明，大多数排放发生在应用后的头几个月，特别是在尿液为 N 源的实验中，ii）春季 N 应用，iii）在细质地土壤上进行，或 iv）显示出高的年排放量。在头几个月内排放较少百分比的实验也具有较低的年净排放量（低于 370 gNO-N ha year），因此在较短的时间内测量不会对计算的 EF 产生重大影响。通过至少测量 60 天的尿液（低估：7.1%）、120 天的粪便和粪浆（4.7%和 5.1%）以及 180 天的 FYM（1.4%）可以获得准确的 EF 估计。至少在温带气候条件下，这些结果在能够通过收集少于 12 个月的数据准确估计年 NO 通量方面是有希望的，在为发展中国家特定的 EF 进行实验时，可以显著节省资源。
