Browsing by Author "Wiltshire, Katy"

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    Assessing the source and delivery processes of organic carbon within a mixed land use catchment using a combined n-alkane and carbon loss modelling approach
    (Springer, 2022-04-08) Wiltshire, Katy; Glendell, M.; Waine, Toby; Grabowski, Robert C.; Meersmans, Jeroen
    Purpose: Understanding fluxes of soil organic carbon (OC) from the terrestrial to aquatic environments is crucial to evaluate their importance within the global carbon cycle. Sediment fingerprinting (SF) is increasingly used to identify land use-specific sources of OC, and, while this approach estimates the relative contribution of different sources to OC load in waterways, the high degree of spatial heterogeneity in many river catchments makes it challenging to precisely align the source apportionment results to the landscape. In this study, we integrate OC SF source apportionment with a carbon loss model (CLM) with the aim of: (i) reducing ambiguity in apportioning OC fluxes when the same land use exists in multiple locations within a catchment; and (ii) identifying factors affecting OC delivery to streams, e.g., buffer zones. Methods: Two main approaches were used in this study: (i) identification of the sources of freshwater bed sediment OC using n-alkane biomarkers and a Bayesian-based unmixing model; and (ii) modelling and analysis of spatial data to construct a CLM using a combination of soil OC content modelling, RUSLE soil erosion modelling and a connectivity index. The study was carried out using existing OC and n-alkane biomarker data from a mixed land use UK catchment. Results: Sediment fingerprinting revealed that woodland was the dominant source of the OC found in the streambed fine sediment, contributing between 81 and 85% at each streambed site. In contrast, CLM predicted that arable land was likely the dominant source of OC, with negligible inputs from woodland. The areas of the greatest OC loss in the CLM were predicted to be from arable land on steeper slopes surrounding the stream channels. Results suggest extensive riparian woodland disconnected upslope eroded soil OC and, concomitantly, provided an input of woodland-derived OC to the streams. It is likely the woodland contribution to streambed OC is derived from litter and leaves rather than soil erosion. Conclusion: This study demonstrates how location-specific OC sources and delivery processes can be better determined using sediment fingerprinting in combination with CLM, rather than using sediment fingerprinting alone. It highlights that, although wooded riparian buffer strips may reduce the impact of upslope, eroded soil OC on waterways, they could themselves be a source of OC to stream sediments through more direct input (e.g., organic litter or leaf debris). Characterising this direct woodland OC as a separate source within future fingerprinting studies would allow the contributions from any eroded woodland soil OC to be better estimated.
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    Data relating to the Thesis: Organic carbon across the terrestrial-to-aquatic continuum: Assessing source and delivery processes using a combined fingerprinting and carbon loss modelling approach
    (Cranfield University, 2023-01-06 11:04) Wiltshire, Katy
    Data relating to the Thesis: Organic carbon across the terrestrial-to-aquatic continuum: Assessing source and delivery processes using a combined fingerprinting and carbon loss modelling approach Soil and sediment data from the Loch Davan catchment, Aberdeenshire. Data includes land use specific: n-alkane concentrations n-alkanes compound-specific stable isotopes neutral lipid fatty acids (NLFA) concentrations NLFA compound-specific stable isotopes Carbon, N and bulk stable isotopes
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    Farm-SAFE v3 - Comparing the financial benefits and costs of arable, forest, and agroforestry systems
    (Cranfield University, 2024-02-06 13:58) Graves, Anil; Burgess, Paul; Wiltshire, Katy; Giannitsopoulos, Michail; Herzog, Felix; Palma, Joao
    Agroforestry systems integrate trees with livestock and/or arable crops on the same parcel of land. Compared to monoculture arable or grass systems, agroforestry systems can enhance soil conservation, carbon sequestration, species and habitat diversity, and provide additional sources of farm income. Farm-SAFE (Financial and Resource use Model for Simulating AgroForestry in Europe) is a spreadsheet-based bio-economic model which has been developed in Microsoft® Excel® to compare the financial benefits and costs of crop-only, tree-only, and agroforestry system over tree rotations of up to 60 years (Graves et al., 2024a). The results are presented in both graphical and tabular form in terms of a net present value and equivalent annual values. A description and user guide is also available (Graves et al., 2024b). Farm-SAFE requires input of tree and crop yields. One way to obtain crop and tree yields in tree-only, agroforestry, and crop-only systems is to use the Yield-SAFE model. Yield-SAFE is a spreadsheet-based biophysical model which has been developed to enable the prediction of the relationship between tree and crop yields over the rotation of the tree component. A copy of the Yield-SAFE model, together with a full description and user guide, is available here. The original Farm-SAFE model was developed with funding from the European Union through the Silvoarable Agroforestry For Europe project (contract number QLK5-CT-2001-00560). The process of creating a default publicly available version of the model has been enabled through the BioForce project funded by the UK Department for Energy Security and Net Zero. Graves, A.R., Burgess, P.J., Wiltshire, C., Giannitsopoulos, M., Herzog, F., Palma, J.H.N. (2024a). Farm-SAFE v3 model in Excel. Cranfield, Bedfordshire, UK: Cranfield University. Graves, A.R., Burgess, P.J., Wiltshire, C., Giannitsopoulos, M., Herzog, F., Palma, J.H.N. (2024b). Description and User Guide for Farm-SAFE v3. January 2024. Cranfield, Bedfordshire, UK: Cranfield University. 42 pp.
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    From field to stream: Tracing streambed organic carbon origins at a catchment scale
    (EGU: European Geophysical Union, 2021-04-30) Wiltshire, Katy; Glendell, Miriam; Waine, Toby; Grabowski, Robert C.; Thornton, Barry; Meersmans, Jeroen