Daniel Evans

University of Sheffield

PhD Project Title

Reductions in nitrous oxide fluxes from agricultural lands following basalt amendment for carbon sequestration: integrating experiments and modelling.

Research Theme(s)

To tackle climate change, any practical means of reducing atmospheric greenhouse gases must be explored. Accelerating natural carbon cycle sequestration processes by spreading crushed calcium and magnesium rich silicate rocks on to soils, enhanced rock weathering (ERW), may reduce greenhouse gas emissions from agricultural land as well as sequester carbon dioxide (CO2).

In Illinois, ERW field studies have alluded to a potential co-benefit; a reduction in soil nitrous oxide (N2O) emissions. N2O is a potent greenhouse gas with a warming effect 300 times greater than CO2. Agriculture is the largest emitter of anthropogenic N2O, therefore, this is a significant finding. However, questions remain; how does the environment (soil conditions, crops, climate) influence the effectiveness of ERW on N2O emission reduction? Which biogeochemical processes linked to N2O emissions are responding to ERW? What is the response of other GHGs (CO2, CH4) and nitrogen gas emissions (HONO, NO and NH3)?

Dan joined LC3M in October 2020 as an ACCE (Adapting to the Challenges of a Changing Environment) PhD student supervised by Prof David Beerling FRS, Dr Maria Val Martin and Dr Dimitar Epihov, University of Sheffield and Prof Ute Skiba, UK Centre for Ecology & Hydrology. His PhD project aims to test whether ERW can reduce emissions of N2O, and other greenhouse gases, from agricultural land in the UK. He will also investigate the mechanisms responsible for reductions in N2O including the effects that basalt-driven soil pH and nutrient status changes may have on the N cycling microbial community in soil. To achieve this, he will be undertaking pot-based experiments in controlled conditions using a variety of different soil types collected from around the UK. Using gas chromatography and a suite of analytical tests, he will establish how the soil nitrogen cycle is responding to ERW. Later in the project, he will be using a biogeochemical model to upscale the results, simulating the UK’s future greenhouse gas responses.

Dan graduated from Plymouth University with a BSc in Geology and an MSc in Environmental Management and was then employed there as a Research Assistant on the FABsoil project, testing the performance of artificial soil recipes and the Soil Carbon Project, studying the link between Cornish farm management and soil organic matter change.