Soil seal development under simulated rainfall: structural, physical and hydrological dynamics

dc.contributor.authorArmenise, Elena
dc.contributor.authorSimmons, Robert W.
dc.contributor.authorAhn, Sujung
dc.contributor.authorGarbout, Amin
dc.contributor.authorDoerr, Stefan H.
dc.contributor.authorMooney, Sacha J.
dc.contributor.authorSturrock, Craig J.
dc.contributor.authorRitz, Karl
dc.date.accessioned2017-11-07T15:55:48Z
dc.date.available2017-11-07T15:55:48Z
dc.date.issued2017-11-01
dc.description.abstractThis study delivers new insights into rainfall-induced seal formation through a novel approach in the use of X-ray Computed Tomography (CT). Up to now seal and crust thickness have been directly quantified mainly through visual examination of sealed/crusted surfaces, and there has been no quantitative method to estimate this important property. X-ray CT images were quantitatively analysed to derive formal measures of seal and crust thickness. A factorial experiment was established in the laboratory using open-topped microcosms packed with soil. The factors investigated were soil type (three soils: silty clay loam - ZCL, sandy silt loam - SZL, sandy loam - SL) and rainfall duration (2-14 minutes). Surface seal formation was induced by applying artificial rainfall events, characterised by variable duration, but constant kinetic energy, intensity, and raindrop size distribution. Soil porosities derived from CT scans were used to quantify the thickness of the rainfall-induced surface seals and reveal temporal seal micro-morphological variations with increasing rainfall duration. In addition, the water repellency and infiltration dynamics of the developing seals were investigated by measuring water drop penetration time (WDPT) and unsaturated hydraulic conductivity (Kun). The range of seal thicknesses detected varied from 0.6 - 5.4 mm. Soil textural characteristics and OM content played a central role in the development of rainfall-induced seals, with coarser soil particles and lower OM content resulting in thicker seals. Two different trends in soil porosity vs. depth were identified: i) for SL soil porosity was lowest at the immediate soil surface, it then increased constantly with depth till the median porosity of undisturbed soil was equalled; ii) for ZCL and SL the highest reduction in porosity, as compared to the median porosity of undisturbed soil, was observed in a well-defined zone of maximum porosity reduction c. 0.24 - 0.48 mm below the soil surface. This contrasting behaviour was related to different dynamics and processes of seal formation which depended on the soil properties. The impact of rainfall-induced surface sealing on the hydrological behaviour of soil (as represented by WDTP and Kun) was rapid and substantial: an average 60% reduction in Kun occurred for all soils between 2 and 9 minutes rainfall, and water repellent surfaces were identified for SZL and ZCL. This highlights that the condition of the immediate surface of agricultural soils involving rainfall-induced structural seals has a strong impact in the overall ability of soil to function as water reservoir.en_UK
dc.identifier.citationArmenise E, Simmons RW, Ahn S, Garbout A, Doerr SH, Mooney SJ, Sturrock CJ, Ritz K, Soil seal development under simulated rainfall: structural, physical and hydrological dynamics, Journal of Hydrology, Available online 1 November 2017en_UK
dc.identifier.cris18814236
dc.identifier.issn0022-1694
dc.identifier.urihttp://dx.doi.org/10.1016/j.jhydrol.2017.10.073
dc.identifier.urihttp://dspace.lib.cranfield.ac.uk/handle/1826/12705
dc.language.isoenen_UK
dc.publisherElsevieren_UK
dc.rightsAttribution 4.0 International
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/
dc.subjectSoil structural sealen_UK
dc.subjectSeal/crust thickness quantificationen_UK
dc.subjectXray Computed Tomography (CT)en_UK
dc.subjectUnsaturated hydraulic conductivity (Kun)en_UK
dc.subjectSoil water repellencyen_UK
dc.subjectSimulated rainfallen_UK
dc.titleSoil seal development under simulated rainfall: structural, physical and hydrological dynamicsen_UK
dc.typeArticleen_UK

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