Land Resources of Auvergne Station
A supplement to the Land Resources of the Victoria River District
Napier, Diane; Edmeades, Bart; Lynch, Brian; McGregor, Robert; Northern Territory. Department of Environment and Natural Resources
E-Publications; E-Books; PublicationNT; Jul-18
Auvergne Station; NT Portion 2676; Victoria River Downs; Victoria River District
This report for Auvergne Station is a supplement to Land Resources of the Victoria River District (2012) and completes the land resource assessment of the district which covers 24 properties and approximately 78 760 km² of pastoral land. Land unit mapping at 1:100 000 describes the landforms, soils and vegetation in the district.
Made available via the Publications (Legal Deposit) Act 2004 (NT)
Table of contents; 1. Introduction; 2. Previous mapping; 3. Survey methodology and data collection; 4. Lithology; 5. Landform; 6. Soil; 7. Soil physical and chemical characteristics; 8. Vegetation; 9. Land evaluation; 10. Soil erosion; 11. Land unit descriptions; 12. References; Appendices 1 - 12.
Soils -- Northern Territory -- Auvergne Station; Land use -- Northern Territory -- Auvergne Station; Geology -- Northern Territory -- Auvergne Station; land resource assessment; land units; soil landscapes; vegetation communities
Northern Territory Government
204 pages ; colour photographs, maps, figures, tables ; 30 cm.
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
http://www.ntlis.nt.gov.au/metadata/export_data?type=html&metadata_id=E3F20A909A8123ADE040CD9B21446CC0; http://hdl.handle.net/10070/245323 [Land resources of the Victoria River District]
Land Resources of Auvergne Station A supplement to the Land Resources of the Victoria River District 25 Inherent Erosion Potential Understanding K factor and its role in determining soil erodibility Soil erodibility is complex and is influenced by many variables such as the soil texture, organic content and also external factors including landscape position, slope length and steepness. The most widely used estimate of inherent erodibility for broad scale surveys comes from the K factor value within the Revised Universal Soil Loss Equation (RUSLE) (Rosewell and Loch 2002). K factor is defined as the soil loss rate per erosion index unit for a specified soil measured on a unit plot (Rosewell and Loch 2002). Ideally, it should be measured directly in the field. Direct measurement is costly and time consuming however an empirical calculation using the soil erodibility nomograph of Wischmeier and Smith (1978) is most commonly used in Australia. Rosewell and Loch (2002) suggest K factor values should be calculated using standard organic matter measurements (Rayment and Lyons 2011), dispersed particle size data (Bowman and Hutka 2002), and field generated measures of surface structure, profile permeability and gravel content. In effect, surface soil texture, structure and organic matter content are the primary attributes that determine whether one soil will be more susceptible to erosion than another, given the same rainfall and landscape position. Generally soils with a high clay content have low K values because the clay particles are fine, bind closely and are not readily detached. Soils with coarse texture such as sands are easily detached but also have low erosion rates because water is able to infiltrate easily though the soil and this decreases runoff. Soils with high silt and fine sand content are the most erodible because the particles are fine, easily detached and tend to form a fine surface crust that leads to high runoff rates. The presence of organic matter in the soil is also an important consideration because it helps to mitigate detachment. K factor applies to the inherent erodibility of in-situ soil and does not take into account the influences from topography, survey area, slope length, gradient or surface soil management related to land use factors. For broad scale surveys such as this one the external factors are very difficult to quantify so the intrinsic soil erodibility is based solely on soil properties alone. Five classes of inherent soil erodibility are recognised by Rosewell and Loch (2002) and are presented in Table 7.1. K factor methodology can be found in Appendix 6. Table 7.2 and 7.3 summarise the K factor for analytical sites sampled on Auvergne. Table 7.1 Soil erodibility classes for soil based on K factor (Rosewell and Loch 2002) Soil erodibility class K factor Very low < 0.010 Low 0.010 0.020 Moderate 0.020 0.040 High 0.040 0.060 Very high > 0.060