Soil is the top layer of the earth’s surface and varies in depth and make-up. It is made up of rock, mineral matter, organic matter, water and air. The ratio of these components and the soil layer depth contributes to creating vastly different types of soils which can be identified by properties including texture, bulk density, colour and structure.
In the South East our soils can roughly be divided into three sections:
1. The elevated landscape of the region to the east of the Naracoorte range and extending to east of Tintinara characterized by soils overlying buried clays and sands.
2. The coastal plains region west of the Naracoorte Range, which has a history of marine influence and comprises a complex of ancient calcarenite dunes and associated lagoon flats.
3. The Mount Gambier region, influenced by consistently high rainfall, sedimentary limestone deposits and volcanic activity.
Soils are an essential ingredient in successful agricultural production and environmental protection and are inextricably linked to the health and well being of other natural resources such as water.
Historically, 80 - 90% of the original native vegetation of our area has been cleared for agriculture and development. As a result of this clearance, and sometimes exacerbated by poor farming practices, some soils in the region have suffered a level of degradation. Although many of the regions soils are naturally of a low capability, some agriculturally induced degradation directly impacts upon the productivity and capability of soils, which in turn has social, environmental and economic repercussions. Some of the most significant land management issues facing the region include increased salinity, sub soil acidity, induced alkalinity in irrigated areas, soil compaction, nutrient leaching, low inherent fertility and erosion.
In the comprehensive NRM Plan currently being developed, soils and land management issues will be defined and described as “Landscape Features”. Examples of these include: Coastal Landscapes, Red Gum Country, Terra Rossa, Range Country, and Sand over Clay Country. The value and significance of each landscape feature will be combined with the threats and risks to the natural resource while considering an integrated management approach with other natural resources.