Land Use Change Impacts on Soil Hydraulic Function

The overarching aim of this PhD is to assess how different land covers, e.g. trees, grass and arable systems, on the same soil type, change hydraulic function and ecosystem service delivery. This will allow us to create empirically derived lookup tables to parameterize models to predict how land use transitions, on the same soil type, will affect soil hydraulic function. This will: (i) improve our understanding of soil hydraulic function in response to land use change, and enable us to account for this change in hydrological and ecosystem service models. (ii) Provide practical solutions to optimising landscapes to maximise water infiltration, retention, and to mitigate flooding and the impacts of extreme weather, and (iii) inform biogeochemical cycling models impacted by moisture retention such as carbon and nutrient cycling models mediated by microbial activity,
This studentship will draw on publically available NERC datasets that include soil parent material, G-BASE, land cover, Countryside Survey and Glastir monitoring. Using a combination of data mining, statistical modelling and GIS the studentship will exploit these unique resources to identify major land use - soil type combinations and conduct a high quality measurement campaign to determine soil hydraulic and biochemical properties, e.g. texture, porosity, carbon, repellency etc. This information will be used to inform and parametrize models (e.g. Hydrus 3D or MM5-LSM6) to demonstrate the likely impact of changes in both land use type, and spatial location on the delivery of ecosystem services. This meets the training needs identified by NERC's Most Wanted Skills Review as well as delivering high quality science with high impact journal articles.
Year 1: Conduct a review of recent research (40+ papers last 10 yrs) from across the globe to determine the impact of land use change on soil hydraulic properties on the same soil type (months 1-6). Use land cover and soil data to identify field site combinations of major relevance for empirical data collection and conduct training in measurement techniques (months 6-12). Year 2: Empirical measurements of soil hydraulic properties e.g. saturated and unsaturated hydraulic conductivity and soil physical properties such as water repellency, SOM, bulk density, texture and conduct laboratory measurements of soil water release using a UMS HYPROP evaporation method and Decagon WP4 (months 12-24). The student can take advantage of the Bangor tree density experiment to explore differences in detail and practice measurement techniques before moving to other field sites. Data analysis of the relationships between hydraulic function and soil properties to produce land management lookup tables for hydraulic properties based on land cover type (e.g. tree, grass, arable) and soil type (months 12-24). Year 3: Identify and use a simple land surface-hydrology model (e.g. MM5-LSM6, ) to synthesise data and test model prediction of the impact of changes in land cover type on hydrological response and ecosystem service provision (months 24-36). Finalise analysis and thesis writing (months 36-42).