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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The effect of hedgerow wild-margins on topsoil hydraulic properties, and overland-flow incidence, magnitude and water-quality
AU - Wallace, E.E.
AU - McShane, G.
AU - Tych, W.
AU - Kretzschmar, A.
AU - McCann, T.
AU - Chappell, N.A.
PY - 2021/3/31
Y1 - 2021/3/31
N2 - Overland and shallow-subsurface flows from agricultural catchments are believed to contribute towards flood-risk and water-quality degradation across the globe. Hedgerows are commonplace agricultural features that may disrupt these rapid hydrological pathways. Research into the hydrological functioning of hedgerows is very limited however, with no field-based quantitative comparison of overland-flows within hedgerows versus other land-uses. This research is the first globally to observe changes in overland-flow incidence, volume and water-quality, alongside topsoil hydraulic and physico-chemical properties, induced by a hedgerow and adjoining wild-margin within a grassland landscape. Observations were conducted within two replicated paired-plots between a hedgerow wild-margin and a bordering pasture, within Cumbria, UK. Compared to adjacent pasture, hedge-margins significantly reduced topsoil dry bulk-density and increased porosity, and significantly increased the topsoil median permeability by a factor of 22–27. Overland-flow models, based on direct observations, highlight that hedge-margins are slower to produce overland-flows than pastures, requiring an equal or greater amount of saturation before the onset of overland-flow generation. Hedge-margins resultantly produced less overland-flow volume, likely due to increased infiltration, percolation and/or evapotranspiration. Soil saturation models, also based on direct observations, confirm pastures saturate faster than hedge-margins, with hedge-margins having extremely variable dynamics in relation to precipitation, whereas pastures have more moderate and consistent dynamics. Overland-flow water-quality from ‘wash-off’ experiments highlight that hedge-margins may store substantially more nitrate (70–260%), nitrate-nitrite (640–650%), and loose sediment (540–3970%) on the ground surface compared to pastures; although further experimentation is needed to determine contaminant mobilization potential.
AB - Overland and shallow-subsurface flows from agricultural catchments are believed to contribute towards flood-risk and water-quality degradation across the globe. Hedgerows are commonplace agricultural features that may disrupt these rapid hydrological pathways. Research into the hydrological functioning of hedgerows is very limited however, with no field-based quantitative comparison of overland-flows within hedgerows versus other land-uses. This research is the first globally to observe changes in overland-flow incidence, volume and water-quality, alongside topsoil hydraulic and physico-chemical properties, induced by a hedgerow and adjoining wild-margin within a grassland landscape. Observations were conducted within two replicated paired-plots between a hedgerow wild-margin and a bordering pasture, within Cumbria, UK. Compared to adjacent pasture, hedge-margins significantly reduced topsoil dry bulk-density and increased porosity, and significantly increased the topsoil median permeability by a factor of 22–27. Overland-flow models, based on direct observations, highlight that hedge-margins are slower to produce overland-flows than pastures, requiring an equal or greater amount of saturation before the onset of overland-flow generation. Hedge-margins resultantly produced less overland-flow volume, likely due to increased infiltration, percolation and/or evapotranspiration. Soil saturation models, also based on direct observations, confirm pastures saturate faster than hedge-margins, with hedge-margins having extremely variable dynamics in relation to precipitation, whereas pastures have more moderate and consistent dynamics. Overland-flow water-quality from ‘wash-off’ experiments highlight that hedge-margins may store substantially more nitrate (70–260%), nitrate-nitrite (640–650%), and loose sediment (540–3970%) on the ground surface compared to pastures; although further experimentation is needed to determine contaminant mobilization potential.
KW - grassland hydrology
KW - hedgerow hydrology
KW - natural flood-risk management
KW - overland-flow
KW - rainfall-runoff processes
KW - transfer-function modelling
KW - Agricultural robots
KW - Agriculture
KW - Catchments
KW - Floods
KW - Land use
KW - Nitrates
KW - Solvents
KW - Water quality
KW - Agricultural catchments
KW - Direct observations
KW - Dry bulk densities
KW - Hydraulic properties
KW - Mobilization potential
KW - Quantitative comparison
KW - Shallow subsurface
KW - Water quality degradation
KW - Wooden fences
KW - flood
KW - grassland
KW - hedgerow
KW - hydraulic property
KW - overland flow
KW - rainfall-runoff modeling
KW - topsoil
KW - water quality
KW - Cumbria
KW - England
KW - United Kingdom
U2 - 10.1002/hyp.14098
DO - 10.1002/hyp.14098
M3 - Journal article
VL - 35
JO - Hydrological Processes
JF - Hydrological Processes
SN - 0885-6087
IS - 3
M1 - e14098
ER -