Improvements to the dispersion status of piped gully soils following reworking and stabilisation by vegetation

Abstract

The physical and chemical properties of sodic gully bank soil material, deposited as in-channel sedimentary structures below a pipe system in alkaline marls, Colorado, USA, were re-analysed for their dispersive status using a new methodology. The original samples were taken from in-gully sedimentary structures with differing densities of established vegetation cover. Taking the more fully established vegetation densities to suggest increasing time since the soil samples were reworked by hydraulic processes, the samples were assigned to a three-point scale (‘fresh-no vegetation’, ‘stabilised: some vegetation’, and ‘stabilised: revegetated’) using detailed site descriptions. These groups were found to be significantly different from each other in terms of the SAR 1 1 Sodium Adsorption Ratio is (SAR) = [Na]/([Ca 2 + Mg 2+] / 2) 0.5 with cation values here remaining as water concentrations obtained from a saturation paste extract, in mmol c − l ( Faulkner et al., 2001). and EC 2 2 Electrical Conductivity, EC in mmhos cm − 1 . . The material's pH was also significantly different following revegetation. The site ‘signatures’ for each class suggest that a model of stabilisation for the soils following revegetation can be usefully described by this approach.