Exploring the Relationship between Soil Water Content and Soil Electrical Conductivity under Typical Land Covers in the Loess Plateau
Abstract
Vegetation changes that are driven by soil conservation measures might result in significant alternation of subsurface water flow patterns and quantities. Tracking of these changes is usually implemented by measuring the soil water content (SWC). A large scale revegetation project was established in the Loess Plateau of China (LPC), introducing a variety of vegetation types. However, the LPC is a semi-arid area with limited water resources and therefore vegetation restoration may not be sustainable. Until now, most of the studies in the LPC have used conventional tools as soil sampling and water content measurements to assess the effect of revegetation on SWC. These methods have been implemented successfully at the plot scale. However, the extrapolation of SWC observations at point scale to larger scales is limited. Alternatively, non-invasive electromagnetic induction (EMI) sensors, which measure the soil electrical conductivity (EC), could be used for mapping the spatiotemporal distribution of the SWC at large scales. To achieve this, the relationship between EC and SWC must be established and verified. In this study, apparent EC (ECa) and SWC observations were measured concurrently under four typical land-covers in the north of the LPC within the Loess Plateau Critical Zone Observatory. Both the average ECa and the average SWC show an increasing trend (shrub > pasture > fallow > crop), which can be expressed as a linear relationship. Moreover, a multi-regression analysis shows that the relation between the SWC and the ECa is also depth related, especially for the grass and shrub land covers. Using 1D and quasi-2D inversions, the ECa was inverted to the 'true' electrical conductivity for each depth. A linear regression with the inverted EC values improved the SWC prediction. This study shows that the use of EMI has great potential in assessing SWC under different land covers. The success of prediction is challenged by the water flow patterns, which are dictated by vegetation cover.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMNS43A..04T
- Keywords:
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- 0416 Biogeophysics;
- BIOGEOSCIENCESDE: 0999 General or miscellaneous;
- EXPLORATION GEOPHYSICSDE: 1824 Geomorphology: general;
- HYDROLOGYDE: 1835 Hydrogeophysics;
- HYDROLOGY