Salinity - Non-watertable (magnesia patches)

Dataset Number1064
Dataset TitleSalinity - Non-watertable (magnesia patches)
CustodianData Authority: Department for Environment and Water
Data Provider: Department for Environment and Water


DescriptionNon-watertable salinity is land where soils contain elevated levels of soluble salts which are not associated with a watertable. The salts have presumably accumulated in the soil either through aeolian accessions and subsequent leaching, or via saline groundwaters which are no longer influencing the land surface. The salts generally occur as subsoil 'bulges', which possibly reflect either the extent of leaching (ie salt cannot be leached any further than the depth of the seasonal wetting front), or an impermeable deep subsoil layer which prevents flushing of the salts INTO substrate materials. ECe is electrical conductivity of a saturation paste of water and soil. Values are based on estimates from EC(1:5) measurements. Areas of high to extreme non-watertable salinity have traditionally been known as 'magnesia patches', and generally occur as bare patches in otherwise vegetated land. Proportion of land affected by magnesia patches is estimated for each Soil Landscape Map Unit. See Salinity - Watertable Induced for an assessment of salinity associated with shallow groundwater. Many map units have components of contrasting land types, with variable soil salinity. Three analysis data classes (including not applicable) have been supplied, as percentage values of Soil Landscape Map Units to be used for the calculation of spatial data statistics. Note: the sum of all percentage values for each map unit totals 100%. Soil Landscape Map Units are categorised INTO five (plus not applicable) legend categories (SAL_NWT_MG), depending on the percentage of land affected by magnesia patches. Note: see Salinity - Non-watertable for a more complete assessment of land affected by non-watertable salinity.
UsageLink to Soil Attribute Descriptions. This dataset has been derived from the Soil Landscape Map Units spatial dataset to be used for map creation or the calculation of spatial data statistics. Used to supply Government, community groups, industry and the general public with up to date regional, subregional and catchment level land and soil attribute information for southern South Australia. The aim is to produce maps, statistics and reports displaying and describing: Land and soil attributes within southern South AustraliaSELECT 1 FROM DUAL; Land surface features affecting land use, land management and productivitySELECT 1 FROM DUAL; Limitations / suitability of land and soil for a range of agricultural and other uses. Independent professional advice should be sought before using this in commercial decisions. Further information: soil and land attributes. Salinity - Non-watertable (magnesia patches) dataset can be viewed on NatureMaps (>Soils>Soil Salinity Attributes). Spatial data downloads are available from Data SA.

Data Quality

LineageThe dataset is based on an interpretation of 1:40,000 stereo colour aerial photography and limited field inspection of landscapes and soils by soil scientists. Soil Landscape Map Unit boundaries were determined after an integration of field observations and recordingsSELECT 1 FROM DUAL; laboratory analysesSELECT 1 FROM DUAL; stereoscopic examination of aerial photographsSELECT 1 FROM DUAL; understanding of regional landscape processes and stratigraphySELECT 1 FROM DUAL; existing soil and geological mapping data. To avoid inconsistencies and confusion, any updates to the Soil and Land Attribute mapping are to be managed by DEWNR Soil and Land Program. This data has been released under a Creative Commons licence. Where products are derived from this data, DEWNR are to be acknowledged, and any changes to the original data should be indicated.
CompletenessComplete. The spatial data is subject to amendment as and when more data become available.
Positional AccuracyThe accuracy is to the scale of mapping (50 metres at 1:50,000 and 300 metres at 1:100,000 mapping scale). The spatial data is to be used at the regional, subregional and catchment level, and can be used to provide property overviewsSELECT 1 FROM DUAL; however, cannot be used at the paddock level. South East, Kangaroo Island, Mount Lofty Ranges and the 'bottom' of Yorke Peninsula have been mapped at 1:50,000. Eyre Peninsula, the main part of Yorke Peninsula, Murray Mallee and Northern Agricultural Districts have been mapped at 1:100,000. Map unit boundaries should be treated as transition zones.

Geographic Extent

Extent NameAgricultural Region - South Australia
Min Easting or Longitude132.25
Min Northing or Latitude-38
Max Easting or Longitude141
Max Northing or Latitude-32.25

Dataset Status

Initially Acquired01-JAN-2000
Last Updated01-JUL-2009
Update FrequencyAs required
Maintenance MethodAs required
LicenseingCC BY (Attribution)


TableNameField AliasData TypeDescription
Landscape.SALAD_Salinity_NonWTable_MgLANSLU CharacterSoil Landscape Map Unit.
Landscape.SALAD_Salinity_NonWTable_MgSAL_NWT_MG CharacterProportion of land affected by magnesia patches. (Legend categories. See layer file for descriptions).
Landscape.SALAD_Salinity_NonWTable_MgV1234 NumberPercentage of map unit not affected by magnesia patches.
Landscape.SALAD_Salinity_NonWTable_MgV7 NumberPercentage of map unit affected by magnesia patches.
Landscape.SALAD_Salinity_NonWTable_MgVX NumberPercentage of map unit which is not applicable.

Contact Information

OrganisationDepartment for Environment and Water
Science Monitoring and Knowledge
Postal AddressGPO Box 1047