Application of the Soil Security Concept to Two Contrasting Soil Landscape Systems—Implications for Soil Capability and Sustainable Land Management

Soil security identifies global challenges and a series of dimensions that are necessary requirements to meet those global challenges using sustainable land management. The soil security concept is applied to two contrasting soil landscape systems with varying climate, landform and soil types. Previous methodologies for assessing land and soil capability are combined within the soil security conceptual approach. The land and soil capability methodologies are used to assess how the soil condition changes in response to the stresses and forcing associated with land management and land and soil degradation processes. It is the soil capability that defines how the soil condition changes between the reference state of the soil condition, or the genoform, and the soil condition under land use, or the phenoform. The conclusion is that soil capability, which is one of the dimensions used to apply the soil security concept, is a complex dimension and has several aspects or further facets to be considered to achieve sustainable land management. It is apparent that in assessing soil capability, the following facets are relevant. I: The capacity of the soil to provide ecosystem services to meet the global challenges outlined for Soil Security. II: The stability of the soil condition to land degradation processes resulting from the effects of land management practices and the environmental stresses on the soil. III: The capacity to recover following degradation. Facets II and III can be considered the resilience. An important conclusion is that the soil capability cannot be assessed without taking into account features of the landscape including climate and landform. Two examples from south eastern Australia of the application of these facets of soil capability to on-ground situations are presented. The Cowra Trough Red Soils in the Australian wheat belt are a set of soils, primarily contributing to meeting the global challenge of food security. The major degradation processes threatening the stability of these soils are water erosion and soil acidification. The Kosciusko National Park in the Snowy Mountains region is primarily contributing to meeting the challenges of water security for the irrigation industry in the Murray Darling Basins and energy security through the production of hydroelectricity. The set of soil landscapes also contributes to biodiversity protection and human health and well-being. The major degradation processes threatening the stability of these soils and their capacity to meet the global challenges are water and wind erosion. A major limitation is the poor capacity of these soils to recover once degraded. Identifying the main ecosystem services provided by the two examples, together with the major risks of land degradation can clarify extension, economic and policy aspects of sustainable land management for the two sets of soil landscapes. For the Cowra Trough Red Soils, management of water erosion and soil acidification are essential for maintaining the contribution of the area to food security. For the Kosciusko National Park, the control of water and wind erosion are essential to maintain the contribution of the area to water and energy security.