Calibrating and using an EM31 electromagnetic induction meter to estimate and map soil salinity in the jarrah and karri forests of south-western Australia

Ten taxa of Acacia were selected from areas of moderate to high soil salinity (electrical conductivities of saturated soil paste extracts (ECe) between 1000 mS m--1 and 4800 mS m-1 at 50-600 mm depth) and sodicity to test the tolerance of young, symbiotic plants to increasing levels of salinity both with and without waterlogging. Nodulated plants, 3 months old, were grown in glasshouse experiments which consisted of four treatments: non-saline drained control (12 weeks); saline drained (12 weeks); non-saline waterlogged (5 weeks); and saline waterlogged (5 weeks). Acacia cyclops, A. brumalis, A. redolens (Ravensthorpe) and A. aff. lineolata had 100% survival after 12 weeks irrigation with saline solution (final ECw = 9500 mS m-1). Generally, the species tested were sensitive to waterlogging with A. patagiata, A. cyclops and A. brumalis being the most sensitive, having 19-44% mortality with no salt in the solution. The combined treatment of salt and waterlogging greatly increased the mortality of plants, with four species having > 70% dead after 5 weeks treatment (ECw = 3900 mS m-1). A. aff. lineolata and A. mutabilis subsp. ,stipulifera were highly tolerant of salt plus waterlogging, with 100% and 96% survival respectively. In salt plus waterlogged treatments, Na+ concentration in phyllodes of all taxa exceeded (0.37-2.13 mmol g-1 dry wt) that taken up by plants in freely drained salt treatments (0.03-0.42 mmol g-1 dry wt). Taxa with the slowest rates of growth tended to accumulate the highest concentrations of Na+ in the uppermost phyllodes. Provenances of A. redolens and A. patagiata collected from sites of high soil salinity (ECe > 2200 mS m-1) had less than half the Na+ concentration in uppermost phyllodes (0.22 mmol -1 dry wt) at the termination of the salt treatment, compared with provenances of the same species collected from moderately saline areas (ECe = 1100 mS m-1). This indicates that Acacia provenances collected from the most saline sites had greater potential to survive high levels of external salinity in the longer term than those from less saline sites.

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Effects of salinisation on riparian plant communities in experimental catchments on the Collie River, Western Australia

Australian Journal of Botany ◽

10.1071/bt02119 ◽

2003 ◽

Vol 51 (6) ◽

pp. 667 ◽

Cited By ~ 24

Author(s):

A. J. Lymbery ◽

R. G. Doupé ◽

N. E. Pettit

Keyword(s):

Species Richness ◽

Plant Species ◽

Western Australia ◽

Soil Salinity ◽

Riparian Vegetation ◽

Plant Species Richness ◽

Perennial Herb ◽

Groundwater Levels ◽

Riparian Plant Communities ◽

Riparian Plant

Although the salinisation of streams has long been recognised as one of Western Australia's most serious environmental and resource problems, there is very little published information on the effects of salinisation on riparian flora and fauna. We studied riparian vegetation in three experimental catchments on the Collie River in Western Australia. The catchments are situated within a 5-km area of state forest and are geologically and botanically similar, but differ in the extent of clearing, groundwater levels and stream salinity. In each catchment, transects were taken perpendicular to the direction of streamflow, and 4-m2 quadrats taken along each transect. Within each quadrat, soil salinity was measured, all plants were identified to species level and percentage cover estimated. The catchments differed significantly in soil salinity, with salinity being greatest in the most extensively cleared catchment and increasing towards the floor of the valley. Plant-species richness, species diversity and species composition were significantly related to soil salinity, both among catchments and among quadrats within the most extensively cleared catchment. Plant-species richness and diversity decreased with increasing soil salinity, an effect that may be partly due to a decline in perennial herb and shrub species. This may have an impact on other components of the riparian ecosystem.

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A RAPID METHOD FOR ESTIMATING WEIGHTED SOIL SALINITY FROM APPARENT SOIL ELECTRICAL CONDUCTIVITY MEASURED WITH AN ABOVEGROUND ELECTROMAGNETIC INDUCTION METER

Canadian Journal of Soil Science ◽

10.4141/cjss86-032 ◽

1986 ◽

Vol 66 (2) ◽

pp. 315-321 ◽

Cited By ~ 37

Author(s):

N. C. WOLLENHAUPT ◽

J. L. RICHARDSON ◽

J. E. FOSS ◽

E. C. DOLL

Keyword(s):

Electrical Conductivity ◽

Soil Salinity ◽

Electrical Resistance ◽

Electromagnetic Induction ◽

Soil Depth ◽

Soil Survey ◽

Soil Electrical Conductivity ◽

Simple Linear Regression ◽

Survey Area ◽

Parent Materials

This study presents a method for calibrating electromagnetic induction instrument readings with saturated paste electrical conductivity (ECe) for field mapping purposes. Each meter reading represents an integration of the apparent soil electrical conductivity (ECa) over the meter’s response depth. To correlate the meter readings with measured ECe within soil depth increments, several pedons representing a range of soil salinity for the survey area were sampled in 30-cm increments to a depth corresponding to the meter response. A weighting procedure based on the meter response-depth function was developed to condense the multiple ECe by depth measurements into a single weighted area specific value. These values were correlated with the apparent soil electric conductivity from the electromagnetic induction instrument by simple linear regression. This technique is designed for soil association of similar parent materials. The resulting regression equation yields a quick reliable equation that avoids complex mathematics and converts the instrument readings into weighted forms of commonly used saturated paste electrical conductivity values. Key words: Soil survey, electrical resistance

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