Exploring the relationship between soil water content and soil electrical conductivity under typical land covers in the northern Loess Plateau, China

Turkeltaub, Tuvia and Wang, Jiao and Cheng, Qinbo and Jia, Xiaoxu and Zhu, Yuanjun Zhu and Shao, Ming-An and Binley, Andrew (2021) Exploring the relationship between soil water content and soil electrical conductivity under typical land covers in the northern Loess Plateau, China. Vadose Zone Journal. ISSN 1539-1663 (In Press)

[img]
Text (Turkeltaub et al. (author copy))
Turkeltaub_et_al._author_copy_.pdf - Accepted Version

Download (1MB)

Abstract

Vegetation changes that are driven by soil conservation measures significantly affect subsurface water flow patterns and soil water status. Much research on water consumption and sustainability of newly introduced vegetation types at the plot scale has been done in the Loess Plateau of China (LPC), typically using local scale measurements of soil water content (SWC). However, information collected at the plot scale cannot readily be up-scaled. Geophysical methods such as electromagnetic induction (EMI) offer large spatial coverage and therefore could bridge between the scales. A non-invasive, multi-coil, frequency domain, EMI instrument was used to measure the apparent soil electrical conductivity (σ_a) from six effective depths under four typical land-covers; shrub, pasture, natural fallow and crop, in the north of the LPC. Concurrently, SWC was monitored to a depth of 4 m depth using an array of 44 neutron probes distributed along the plots. The measurements of σ_a for six effective depths and the integrated SWC over these depths, show consistent behavior. High variability of σ_a under shrub cover, in particular, is consistent with long term variability of SWC, highlighting the potential unsustainability of this land cover. Linear relationships between SWC and σ_a were established using cumulative sensitivity forward models. The conductivity-SWC model parameters show clear variation with depth, despite lack of appreciable textural variation. This is likely related to the combined effect of elevated pore water conductivity as was illustrated by the simulations obtained with water flow and solute transport models. The results of the study highlight the potential for the implementation of the EMI method for investigations of water distribution in the vadose zone of the LPC, and in particular for qualitative mapping of the vulnerability to excessive vegetation demands, and hence unsustainable land cover.

Item Type:
Journal Article
Journal or Publication Title:
Vadose Zone Journal
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1111
Subjects:
ID Code:
161576
Deposited By:
Deposited On:
01 Nov 2021 15:16
Refereed?:
Yes
Published?:
In Press
Last Modified:
03 Dec 2021 09:30