Modelling soil erosion and soil carbon dynamics in agricultural systems
Dr Marcelo Valadares Galdos (SEE), Prof. Pippa Chapman (SoG)Contact email: firstname.lastname@example.org
Besides supporting food, feed, fuel and fibre production, soils provide ecosystems services such as storing carbon, filtering water and maintaining biodiversity. Fertile soil is being lost at the rate faster than it can recover, primarily from inadequate agricultural management practices and by climate change. Soil carbon (C) content, one of the main indicators of soil quality and resilience, has declined globally. Climate change is expected to increase the incidence of highly erosive precipitation events in the UK, according to high resolution weather forecast models.
Soil conservation practices are a key aspect of the climate-smart approach to global warming mitigation and adaptation, and include reduced soil disturbance; maintenance of permanent soil cover; and increased crop diversity through rotations and intercropping. Process-based models integrate soil, crop and climate information to evaluate the impact of management systems on soil erosion and soil C stocks. Although most biogeochemical models represent soil C dynamics and erosion separately, there is a need to integrate those processes, including feedbacks and interactions. The omission of soil C erosion in crop models can lead to overestimations of C losses by decomposition, and in the potential for soil C sequestration in agricultural soils at regional and global scales.
The purpose of this PhD project is to assess the impact of soil conservation practices on soil carbon dynamics and erosion in selected catchments in Yorkshire using process-based models and climate scenarios, interacting with researchers from the UK Met Office, ICAS/SEE and the School of Geography. Specific objectives include:
1. Assessing soil losses by erosion and soil C dynamics in agricultural land in the River Ouse catchment.
2. Evaluating the impact of conservation management practices on reducing erosion and increasing soil C sequestration in agricultural land.
3. Estimating the effect of climate change on erosion and soil C cycling, including increased temperatures and the higher incidence of extreme precipitation events.
4. Contributing to the inclusion of SOC erosion processes in the improvement of Earth System Models (ESM) at the global scale.
The geographical scope for the project will be the River Ouse catchment in North Yorkshire, covering approximately 4,847 km2. 95% of this catchment is comprised of agricultural land, with nearly 55% of that classified as excellent to moderate quality productive land. For future climate scenarios, the student will use UK Climate Projections 2018 (UKCP18), developed by the Met Office Hadley Centre Climate Programme, specifically downscaled climate projections (at the 2.2km scale) using the IPCC Representative Concentration Pathway (RCP) 8.5. The student will parameterize, calibrate and evaluate process-based models using existing datasets from the selected case studies, and will collect additional soil, climate, land use and land management data as needed. The main models used in this project will be JULES-Crop (Osbone et al. 2015), Roth-C (Jenkinson, 1990) and APEX (Gassmann et al. 2009).
The project will enable relevant advancements to be made in understanding the connection between erosion processes and soil C dynamics in agricultural land. This research has potential applications in catchment management, helping identify sustainable agricultural practices that can reduce the environmental impact of food production while maintaining or increasing yields. It will also contribute to adaptation strategies for climate change in the region, by modelling the impact of future climate scenarios on erosion and carbon cycling processes. Finally, it can help improve the understanding of the global carbon cycle through potential applications of the research outcomes in the improvement of Earth System Models.
The student will work under the supervision of Dr Marcelo Galdos and Professor Pippa Chapman, within the Faculty of Environment, University of Leeds. The successful candidate will develop a range of research skills, including modelling, field sampling, chemical analysis, statistical analysis and data interpretation, 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. The student should have a keen interest in soil processes and environmental issues with a strong background in one or more of physical geography, earth sciences, soil science, environmental sciences or related discipline. Strong analytical/statistical/fieldwork skills are desirable but not essential, as full training will be provided during the PhD.
Related undergraduate subjects:
- Applied mathematics
- Environmental conservation
- Environmental science
- Natural resource management
- Physical geography
- Soil science
- Sustainability and environmental management