Dr Richard Grayson (School of Geography), Prof. P. Chapman (School of Geography) & Dr Ross Morrison (Centre for Ecology and Hydrology)

Project Summary

The UK Government are committed to decarbonising all sectors of the UK economy to meet the target of net zero greenhouse gas (GHG) emissions by 2050. Emissions from the agricultural sector accounted for 11% (55 MtCO2e) of UK GHG emissions in 2019, mainly stemming from livestock, agricultural soils, and farm machinery. Thus, emissions reductions from agriculture have the potential to make significant contributions to the UK Net Zero ambition, as well as the potential for negative GHG emissions through capturing and storing (sequestering) more carbon in agricultural soils and vegetation; increasingly referred to as carbon farming. It is anticipated that by 2030, 75% of farms in England will engage in low carbon farming practices, increasing to 85% by 2035. At the same time, each devolved nation of the UK is developing post-Brexit national agri-environment schemes (e.g., Environmental Land Management schemes, ELMs, in England) that prioritise the delivery of public goods. This will see farming and the countryside contributing significantly to environmental goals, including addressing climate change.

Intensive agriculture has led to soil degradation, especially a reduction in soil organic matter content and the amount of carbon stored in soils. This has resulted in declining soil health and negative impacts on agricultural output. Regenerative agriculture is gaining traction as a means to reduce and/or reverse the past environmental impacts of farming through renewed sequestration of carbon in soils, improvements in soil health and fertility, and reductions in GHG emissions to the atmosphere. Regenerative farming practices that have been shown to enhance carbon storage in agricultural systems include: minimal or zero tillage, cover cropping, addition of organic amendments, diversity of plant species, and the reintroduction of livestock in crop rotations (mixed farming), amongst others. However, the rate of carbon sequestration is dependent on soil texture, soil drainage characteristics, climate and length of time since regenerative farming practices were adopted.

Despite the UK government’s commitment to reducing agricultural GHG emissions and push to encouraging carbon farming practices/regenerative agriculture, there remains a major lack of evidence on GHG fluxes in agriculture. Very few studies have deployed Eddy Covariance to measure field scale GHG fluxes in agricultural systems, and none have compared conventional and regenerative agricultural management practices. As such, there is a real need to better understand the role of different agricultural practices on GHG fluxes and C sequestration across the diversity of agricultural systems in the UK.

 

Aims and Objectives

This project offers an exciting opportunity to make a significant contribution to the UK transition towards sustainable agriculture and net zero. Building on work from the past three years, the project will exploit long term Eddy Covariance measurements and automatic chamber experiments to better understand the spatial and temporal variability in GHG fluxes within arable, grassland and outdoor pig systems, and to explore how changes in land management and climatic forcing control these fluxes.

Depending on your particular research interests, the studentship could address a combination of the following objectives:

I. Quantify Land-Air fluxes of water, carbon and nitrogen using Eddy Covariance flux towers and automatic chambers from different agroecosystems.

II. Determine the net ecosystem carbon and water balance of common UK agricultural crops

III. Investigate the impact of regenerative agricultural practices on GHG fluxes and carbon sequestration

IV. Explore the biological and physical processes that drive variability in agricultural GHG fluxes over space and time.

Training

The student will work under the supervision of Dr Richard Grayson and Professor Pippa Chapman within the Faculty of Environment, University of Leeds, plus Dr Ross Morrison at the Centre for Ecology and Hydrology (CEH), who have expertise in all aspects of the project. Fieldwork will be conducted in the UK, and the findings will be of international relevance. The student will have access to excellent training and field and laboratory resources at the University of Leeds and CEH. This includes three Eddy Covariance (EC) flux towers located the University of Leeds Research Farm which focus on observing land-atmosphere fluxes of carbon dioxide (CO₂) and water vapour (evapotranspiration). CEH also operate a wider network of Eddy Covariance (EC) flux towers some of which measure other trace GHG gas fluxes such as methane (CH₄) and nitrous oxide (N₂O). The student will also have access to a soil GHG flux chamber system with an analyser that is capable of measuring CO₂ CH₄, N₂O and H₂O and a mobile gas analyser capable of measuring CO₂, CH₄ and H₂O

The successful candidate will develop a range of research skills, including experimental design, field sampling, statistical analysis and data interpretation, modelling, academic writing skills and giving presentations. Training will be provided in field/laboratory health and safety procedures and the use of field and analytical equipment.