Nitrogen fertiliser interactions with urine deposit affect nitrous oxide emissions from grazed grasslands

Cattle excreta deposited on grazed pastures are responsible for one fifth of the global anthropogenic nitrous oxide (N2O) emissions. One of the key nitrogen (N) sources is urine deposited from grazing animals, which contributes to very large N loadings within small areas. The main objective of this plot study was to establish whether the application of N fertiliser and urine deposit from dairy cows synergistically interacts and thereby increases N2O emissions, and how such interaction is influenced by the timing of application. The combined application of fertiliser (calcium ammonium nitrate) and urine significantly increased the cumulative N2O emissions as well as the N2O emission factor (EF) from 0.35 to 0.74 % in spring and from 0.26 to 0.52 % in summer. By contrast, EFs were lower when only fertiliser (0.31 % in spring, 0.07 % in summer) or urine was applied (0.33 % in spring, 0.28 % in summer). In autumn, N2O emissions were larger than in other seasons and the emissions from the combined application were not statistically different to those from either the separately applied urine or N fertiliser (EF ranging from 0.72 to 0.83, p-value < 0.05). The absence of significant synergistic effect could be explained by weather conditions, particularly rainfall during the three days prior to and after application in autumn. This study implies that the interactive effects of N fertilisation and urine deposit, as well as the timing of the application on N2O emission need to be taken into account in greenhouse gas emission inventories

Nitrogen fertiliser interactions with urine deposit affect nitrous oxide emissions from grazed grasslands

peer-reviewedCattle excreta deposited on grazed pastures are responsible for one fifth of the global anthropogenic nitrous oxide (N2O) emissions. One of the key nitrogen (N) sources is urine deposited from grazing animals, which contributes to very large N loadings within small areas. The main objective of this plot study was to establish whether the application of N fertiliser and urine deposit from dairy cows synergistically interacts and thereby increases N2O emissions, and how such interaction is influenced by the timing of application. The combined application of fertiliser (calcium ammonium nitrate) and urine significantly increased the cumulative N2O emissions as well as the N2O emission factor (EF) from 0.35 to 0.74 % in spring and from 0.26 to 0.52 % in summer. By contrast, EFs were lower when only fertiliser (0.31 % in spring, 0.07 % in summer) or urine was applied (0.33 % in spring, 0.28 % in summer). In autumn, N2O emissions were larger than in other seasons and the emissions from the combined application were not statistically different to those from either the separately applied urine or N fertiliser (EF ranging from 0.72 to 0.83, p-value < 0.05). The absence of significant synergistic effect could be explained by weather conditions, particularly rainfall during the three days prior to and after application in autumn. This study implies that the interactive effects of N fertilisation and urine deposit, as well as the timing of the application on N2O emission need to be taken into account in greenhouse gas emission inventories.Teagas

Priorities for mitigating greenhouse gas and ammonia emissions to meet UK policy targets

Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However, agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely acknowledged that there is a need to further reduce and mitigate emissions across sectors, including agriculture to address the climate emergency and emissions gap. This discussion paper outlines a collation of opinions from a range of experts within agricultural research and advisory roles following a greenhouse gas and ammonia emission mitigation workshop held in the UK in March 2022. The meeting identified the top mitigation priorities within the UK’s agricultural sector to achieve reductions in greenhouse gases and ammonia that are compatible with policy targets. In addition, experts provided an overview of what they believe are the key knowledge gaps, future opportunities and co-benefits to mitigation practices as well as indicating the potential barriers to uptake for mitigation scenarios discussed

Greenhouse gas and ammonia emission mitigation priorities for UK policy targets

Acknowledgements Many thanks to the Association of Applied Biologist’s for organising and hosting the ‘Agricultural greenhouse gases and ammonia mitigation: Solutions, challenges, and opportunities’ workshop. This work was supported with funding from the Scottish Government’s Strategic Research Programme (2022-2027, C2-1 SRUC) and BBSRC (BBS/E/C/000I0320 and BBS/E/C/000I0330). We also acknowledge support from UKRI694 BBSRC (United Kingdom Research and Innovation-Biotechnology and Biological Sciences 695 Research Council; United Kingdom) via grants BBS/E/C/000I0320 and BBS/E/C/000I0330. and Rothamsted Research's Science Initiative Catalyst Award (SICA) supported by BBSRC.Peer reviewedPublisher PD

Effect of Reynolds number and lithium cation insertion on titanium anodization

This work studies the influence of using hydrodynamic conditions (Reynolds number, Re = 0 to Re = 600) during Ti anodization and Li+ intercalation on anatase TiO2 nanotubes. The synthesized photocatalysts were characterized by using Field Emission Scanning Electron Microscope (FE-SEM), Raman Confocal Laser Microscopy, Electrochemical Impedance Spectroscopy (EIS), Mott-Schottky analysis (M-S), photoelectrochemical hydrogen production and resistance to photocorrosion tests. The obtained results showed that the conductivity of the NTs increases with Li+ intercalation and Re. The latter is due to the fact that the hydrodynamic conditions eliminate part of the initiation layer formed over the tube-tops, which is related to an increase of the photocurrent in the photoelectrochemical water splitting. Besides, the photogenerated electron-hole pairs are facilitated by Li+ intercalation. Finally, this work confirms that there is a synergistic effect between Re and Li+ intercalation

Synergistic effect between hydrodynamic conditions during Ti anodization and acidic treatment on the photoelectric properties of TiO2 nanotubes

In the present work, the combined influence of controlled hydrodynamic conditions during Ti anodization and the acidic treatment with HClO4 on the photoelectric properties of mixed anatase/rutile TiO2 nanotubes has been studied. Anodized samples were analyzed by means of Field Emission Scanning Electronic Microscopy (FE-SEM), Confocal Raman Microscopy, electrochemical measurements (electrochemical impedance spectroscopy and Mott-Schottky analysis) and photoelectrochemical measurements. It has been observed that the use of hydrodynamic conditions increases the surface area of nanotubes, while acidic treatment enhances their conductivity. Besides, there is a clear synergistic effect between the hydrodynamic conditions and the acidic treatment, which results in higher photocurrent densities for the treated nanotubes formed under hydrodynamic conditions.Authors would like to express their gratitude for the financial support to the Ministerio of Economia y Competitividad (Project CTQ2013-42494-R).Sánchez Tovar, R.; Fernández Domene, RM.; Martinez Sanchez, A.; Blasco Tamarit, ME.; García-Antón, J. (2015). Synergistic effect between hydrodynamic conditions during Ti anodization and acidic treatment on the photoelectric properties of TiO2 nanotubes. Journal of Catalysis. 330:434-441. https://doi.org/10.1016/j.jcat.2015.08.002S43444133

Assessing the impact of long-term soil phosphorus on N-transformation pathways using 15N tracing

peer-reviewedA laboratory incubation study was conducted on a temperate grassland soil to quantify the main mineral nitrogen (N) transformation rates and pathways via a15N tracing approach. Soil samples were taken from a long-term phosphorus (P) trial to investigate the effects on gross N-transformations under high and low phosphorus amendment. The soils were incubated over a 2-week period and treated with ammonium-nitrate (NH4NO3) which was applied to the soil both with and without a glucose amendment and labelled with 15N either on the ammonium (NH4+) or nitrate (NO3−) moiety at 50% atom enrichment. The results showed immobilisation to greatly outweigh mineralisation and that NO3− was predominantly produced via heterotrophic nitrification. Individual pathways for NO3− production were quantified including oxidation of NH4+, recalcitrant and labile organic N. Oxidation of labile organic N to NO3−, a newly considered pathway, accounted for between 63 and 83% of total NO3− production across the various treatments and P levels. This process was significantly higher in the low-P rather than the high-P soils (p < 0.05), highlighting the effect of soil P on the microbial community.National Development Pla