Biogeochemistry research (BGR) programme
Climate change is one of the most important problems facing the world and there now is overwhelming evidence that increased emissions of greenhouse gases (GHGs) is the factor most responsible for global warming. Agriculture accounts for 27% of GHG emissions in Northern Ireland (NI), compared to only 9% in the UK as a whole and reflects the importance of the agri-food industry to the NI economy. The NI Executive’s goal of reducing GHG emissions by 35% in 2025 relative to 1990 levels, therefore will necessitate significant reductions in agricultural emissions. However, there is a high degree of scientific uncertainty over such emissions and a need to develop improved methodologies for measuring, reporting and verifying them. Ultimately, strategies are needed to minimise the C footprint of NI agriculture, and particularly in relation to intensive livestock production.
The BGR Programme is providing the grass-based livestock industry in NI (and further afield) with innovative strategies for mitigating NH3 and N2O emissions and enabling it to contribute to the 35% reduction (of 1990 levels) in GHG emissions (by 2025) as stipulated by the NI Executive.
Over the past 5 years, biogeochemistry research in AEB has focused on five key areas:
- reducing uncertainty in the UK GHG inventory and generating regional specific emissions factors for NI;
- understanding the factors controlling nitrous oxide (N2O) production so that transformation processes can be manipulated to produce nitrogen gas (N2) which is benign;
- quantifying indirect N2O emissions from ammonia (NH3) volatilisation and nitrogen leaching;
- evaluating strategies for reducing NH3 and GHG emissions from fertilisers, manures and grazing returns; and
- investigating the potential for soil carbon (C) sequestration to offset GHG emissions from agriculture.
To address the challenge of mitigating climate change whilst enabling the
Examples of key externally funded research projects in these areas are:
- “Maximising the efficiency of slurry-N and urea-N utilization by grassland using nitrification and urease inhibitors as a strategy for environmental protection” - Research Stimulus Fund Programme (2007-2011). A collaborative project with Teagasc and University College Dublin (UCD) investigating the efficacy and cost benefit of using nitrification and urease inhibitors to reduce GHG emissions and improve slurry and fertiliser N utilisation by Irish grassland, in which AEB took the lead in stable isotope (15N) techniques to measure N2O and N2 emissions and gross soil N transformations.
- “To improve the UK agricultural greenhouse gas inventory for nitrous oxide” (AC0116) (2010-2015). A consortium of 8 leading UK research institutes contributing to the development of IPCC ‘Tier 2’ and ‘Tier 3’ regional specific emission factors for N2O, to improve the UK greenhouse gas inventory, in which AEB is providing experimental field sites and expertise for quantifying N2O emissions from synthetic nitrogen fertilisers and animal manures and developing mitigation strategies to reduce these emissions.
- “Carbon sequestration in permanent pasture” - funded by the Department of Agriculture, Food and Marine (Republic of Ireland) (2012-2015). A collaborative project with Teagasc, UCD, Trinity College Dublin and University of Limerick, in which AEB is investigating the effects of repeated applications of pig and cow slurry to grassland over a 44-year period on soil C sequestration and fractionation at different soil depths.
The following are examples of key research outputs in this respect:
- Our expertise in measurement of N2O emissions and use of 15N isotope techniques is leading to the development of mitigation strategies to reduce both direct and indirect agricultural N2O emissions.
- Replacing calcium ammonium nitrate (CAN) with urea amended with a urease inhibitor has been shown to have potential as a mitigation strategy to reduce N2O emissions under Irish conditions, whilst maintaining grass production.
- Practical interventions arising from the BGR programme and implemented on pilot dairy farms in NI to mitigate N2O and NH3 emissions, were published in the Greenhouse Gas Implementation Partnership Phase I Report 2014 Greenhouse gas implementation partnership phase one report 2014 to demonstrate how the NI farming industry is being proactive in tackling these and other gaseous emissions (e.g. CH4).
- Researchers in the BGR programme contributed to the Global Research Alliance booklet on ‘Nitrous oxide chamber methodology guidelines’ published in December 2012.
Internationally, the BGR programme is making a highly significant contribution to biogeochemical research as demonstrated by a strong publication record and collaborative links with leading international research organisations including the University of Giessen (Germany), University of East Anglia, University of Aberdeen, ADAS, University of Bangor, Rothamsted, SRUC, CEH, Teagasc and UCD. Our researchers have made significant contributions as expert assessors for international organizations including the Joint Programming Initiative on Agriculture, Food Security and Climate Change (FACCE-JPI), the Natural Environment Research Council (NERC), UK, Fonds québécois de la recherche sur la nature et les technologies (FQRNT), Québec, Canada, and the Ministry of Primary Industries in New Zealand. They have also delivered keynote addresses at several recent international conferences including the International Fertiliser Society, International Fertiliser Industry Association in Rio de Janeiro, Brazil and the UK-China Sustainable Agriculture Innovation Network in Beijing, China.
Key international scientific outputs arising from the BGR Programme include:
- Mueller, C., Laughlin, R. J., Christie, P., Watson, C. J. (2011). Effects of repeated fertilizer and cattle slurry applications over 38 years on N dynamics in a temperate grassland soil. Soil Biology and Biochemistry, 43(6):1362-1371. (Impact Factor 4.41).
- McGeough, K.L., Laughlin, R. J., Watson, C. J., Muller, C., Ernfors, M., Cahalan, E., Richards, K. G. (2012). The effect of cattle slurry in combination with nitrate and nitrification inhibitor dicyandiamide on in situ nitrous oxide and dinitrogen emissions. Biogeosciences, 9:4909-4919. (Impact factor 3.75)
- Chadwick, D., Cardenas, L., Misselbrook, T., Smith, K., Rees, R., Watson, C.J., McGeough, K.L., Williams, J., Cloy, J., Thorman, R., Dhanoa, M. (2014). Optimizing chamber methods for measuring nitrous oxide emissions from plot-based agricultural experiments. European Journal of Soil Science, 65:295-307. (Impact Factor 2.39).