Unsaturated hydraulic properties of vegetated soil under single and mixed planting conditions

Abstract

Unsaturated hydraulic properties of vegetated soil under single and mixed planting conditions Ni, J. J .; Leung, Anthony; Ng, C. W. W. Published in: Géotechnique DOI:10.1680/jgeot.17.t.044 Publication date: 2018 Document Version Peer reviewed version Link to publication in Discovery Research Portal Citation for published version (APA):Ni, J. J. ., Leung, A., & Ng, C. W. W. (2018). Unsaturated hydraulic properties of vegetated soil under single and mixed planting conditions. Géotechnique. https://doi.org/10.1680/jgeot.17.t.044 General rightsCopyright and moral rights for the publications made accessible in Discovery Research Portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from Discovery Research Portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain.• You may freely distribute the URL identifying the publication in the public portal. Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Accepted manuscript doi:10.1680/jgeot.17.t.044 Accepted manuscriptAs a service to our authors and readers, we are putting peer-reviewed accepted manuscripts (AM) online, in the Ahead of Print section of each journal web page, shortly after acceptance. DisclaimerThe AM is yet to be copyedited and formatted in journal house style but can still be read and referenced by quoting its unique reference number, the digital object identifier (DOI). Once the AM has been typeset, an 'uncorrected proof' PDF will replace the 'accepted manuscript' PDF. These formatted articles may still be corrected by the authors. During the Production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. Version of recordThe final edited article will be published in PDF and HTML and will contain all author corrections and is considered the version of record. Authors wishing to reference an article published Ahead of Print should quote its DOI. When an issue becomes available, queuing Ahead of Print articles will move to that issue's AbstractEffects of plant roots on changes of soil hydraulic properties, including soil water retention curves (SWRC) and soil hydraulic conductivity functions (SHCF), are not well understood, especially when soil is unsaturated and vegetated with multiple plant species. This note aims to quantify the root effects on both SWRC and SHCF of silty sand using the instantaneous profile method. Four types of vegetated soil, namely bare, grass-only, tree-only and mixed tree-grass soils, were subjected to a controlled drying-wetting cycle in a plant room. Plant roots affect the air-entry value, saturated hydrau...

The Effect of Willow (Salix sp.) on Soil Moisture and Matric Suction at a Slope Scale

“…The denser vegetation established at the toe of the monitored hillslope may have been due to more optimal conditions for plant growth in terms of soil water and nutrients availability, which tend to accumulate naturally downslope (e.g., [34]). It is worth noting that willow-vegetated soil exhibited higher θv levels than fallow soil during part of the monitoring period (Figures 2 and 3), suggesting that vegetated soil can have a higher water retention capacity than fallow soil (e.g., [21]). The latter may be associated with the lower bulk density (i.e., higher soil porosity and thus, volume to be filled with water [18]) observed in the willowvegetated transect, which in turn is influenced by the plant cover through the incorporation of organic matter into the soil [41] and through soil structural changes related to the root system [5,42].…”

“…In this regard, the relationship between the soil moisture and matric suction established through the soil water characteristic curve (SWCC; [19]) provides a good basis to bridge soil hydrology and mechanics [18]. Still, SWCCs for plant-soil composites either are difficult to obtain or have not yet been reported accurately (e.g., [3,20,21]). Moreover, only a handful of field studies have been undertaken to collect field-based knowledge on how vegetation influences the distribution of soil moisture and matric suction within hillslopes (e.g., [3,16,22]).…”

A Novel Approach to Interpret Soil Moisture Content for Economical Monitoring of Urban Landscape

“…The reason for this may be blockage of pores due to root permeation. However, some other studies [21][22][23] show that water-holding capacity decreases due to the decay and shrinkage of roots. Accurate measurements of moisture content in GI is vital to analyse evapotranspiration, groundwater recharge and cloud formation (i.e., soil-plant-atmosphere interaction [24,25])…”

Simplified Relation Model of Soil Saturation Permeability Coefficient and Air-Entry Value and Its Application

“…Chui et al [6] analyzed two geological cases in Singapore, and they used the ordinary leather method and the simple Kriging method (SK) to estimate the spatial variability of the air-entry value of the soil. Ni et al [7] used the instantaneous profile method to quantify the influence of plant roots on the air-entry value, and they found that the presence of roots significantly increased the airentry value of silt. Under mixed planting with rotted roots, the vegetation soil showed a significant decrease in the air-entry value.…”