Dominant soil orders in Tasmania: distribution and selected properties

Abstract

Dermosols (24%) and Organosols (14.8%) are the dominant soil orders in Tasmania, with the mapped occurrence of >985 000 ha of Organosols in Tasmania being the greatest in any Australian State. Tenosols and Rudosols are well represented in all 3 natural resource management (NRM) regions and Kurosols are more prevalent in the NRM North and South Regions. Tasmania has a greater proportion of Ferrosols (8.4%) than the whole of Australia (0.8%) and these soils are some of the most productive in Tasmania with >25 000 ha used for cropping. Hydrosols (3.7%) are probably underestimated. Chromosols (5.3%) and Sodosols (1.6%) are relatively minor soils in Tasmania, occurring predominantly in lower rainfall areas with <800 mm average annual rainfall. Parent material is a strong determinant of soil distribution in Tasmania but many Soil Orders occur on a wide range of parent materials. Brown suborders are predominant in several Soil Orders. A large part of Tasmania (2 658 000 ha) is mapped as being used for conservation, with one-third of this area being mapped as Organosols. The mean surface horizon soil carbon content (4.3%) is relatively high, likely due to Tasmania’s relatively high annual rainfall and cool temperatures. Most Soil Orders have moderately acid surface horizons but soils on calcareous parent materials are neutral to strongly alkaline (Tenosols and Calcarosols). The dataset covers the mainland extent of Tasmania, as well as all large islands around Tasmania’s coastline including King, Flinders, Hunter, Three Hummock, Robbins, Cape Barren, Clarke, and Maria Islands.