Basic Concepts: Degradation, Resilience, and Rehabilitation
Winfried E. H. Blum
Abstract
Many kinds of soil processes, such as degradation, resilience and rehabilitation, can only be understood on the basis of an energy concept for soil systems. On this basis, soil can be described as a pool of energy at the interface between atmosphere, geosphere, hydrosphere and biosphere, based on three forms of energy, which derive from three different sources: gravity, an important factor for all processes occurring in the soil, because it controls to a great extent the energy for the movement of solids, liquids and gases within the soil, from the soil into adjacent media and vice versa. energy conserved in the rock parent material, especially in the many different forms of minerals (e.g., micas, feldspars, pyroxenes, quartz and others) and the binding forces between them (texture and structure of rocks), which have been formed through orogenesis under high energy input (pressure and temperature), which is still present in the chemical composition and crystal structure of these minerals and rocks, with two important consequences for soil formation as well as for soil degradation: There are very different rock parent materials (magmatic, metamorphic and sedimentary) with very different chemical and mineralogical compositions, thus causing very different energy levels or pools in the respective soils derived from them. These energy pools influence all kinds of processes within the soil and with its outer sphere. This energy cannot be renewed (in contrast to solar energy), except in cases of new orogenesis, e.g., volcanic activity. solar energy, furnishing the organic component of the soil as well as sustaining all forms of life within it, has two different forms, which are important for soil processes: Direct and indirect (diffuse) solar radiation, including energy exchange in the soil and between soil and atmosphere. Medium-term to long-term forms of energy, deriving from energy pools stored in the biomass and all kinds of organic carbon (humus and other forms in and above the soil).