Dataset Number 1071 Dataset Title Sodium Toxicity (depth to toxic layer) Custodian Data Authority: Department for Environment and Water Data Provider: Department for Environment and Water

Description Description Many soils in the drier parts of southern South Australia have very high levels of deep subsoil sodicity (ie exchangeable sodium percentages (ESP) exceeding 25), generally at depths of between 50 and 100 cm, sometimes shallower. These conditions are invariably associated with high pH, moderate salinity and often high boron concentrations, all of which are natural features of these soils. They are not necessarily associated with poor soil structure. There is some evidence to suggest that these high levels of sodicity are toxic to some plants, particularly horticultural species. If there are toxic effects, it is reasonable to assume that in some years, the sodicity is preventing optimum water use efficiency, and could therefore be contributing to rising watertables. In practice, neither gypsum nor any other ameliorant will have any significant effect on these soils, due to the very high rates required and the difficulty of incorporation to the required depth. The use of plants with sodium tolerance is one solution. This implies cultivar selection focussed on sodium tolerance or the use of naturally occurring plants with sodium tolerance.Estimates of ESP are based on extrapolation of laboratory analyses between similar soil materials and soils. Five (plus not applicable) estimated Depth to Sodium Toxicity analysis data classes 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%. Five (plus not applicable) legend categories (TOX_NA_D) have been determined by rating the most severely affected landscape component, provided it occupies at least 30% of the area of the Soil Landscape Map Unit. Usage Link 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. Sodium Toxicity (depth to toxic layer) dataset can be viewed at NatureMaps (>Soils>Soil Chemistry Attributes). Spatial data downloads are available from Data SA.

Data Quality Lineage The 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. Completeness Complete. The spatial data is subject to amendment as and when more data become available. Positional Accuracy The 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 Name Agricultural Region - South Australia Min Easting or Longitude 132.25 Min Northing or Latitude -38 Max Easting or Longitude 141 Max Northing or Latitude -32.25

Dataset Status Initially Acquired 01-JAN-2000 Last Updated 01-JUL-2009 Update Frequency As required Maintenance Method As required AusGOAL CC BY (Attribution)

Attributes

Contact Information Organisation Department for Environment and Water Science Monitoring and Knowledge Postal Address GPO Box 1047 ADELAIDE 5001 Email DEWNR.CustomerServiceCentre@sa.gov.au