Understanding Soil Systems and Earth's Surface Dynamics

The Soil

The soil is a complex system that forms the outermost layer of the Earth, at the interface or boundary between various systems that gather on the Earth's surface: the lithosphere, which provides the mineral matrix of soil, and the air, hydrosphere, and biosphere that alter the matrix, giving rise to the soil itself. The study of the dynamics of soil samples follows an evolutionary process which fully applies the concepts of ecological succession.

Causes of Soil Degradation and Destruction

• Weathering: The alteration experienced by rocks in contact with water, air, and living things.
  • Physical or Mechanical Weathering: This occurs when lower temperatures cause water in rock crevices to freeze; as it increases in volume, it causes fractures.
  • Chemical Weathering: This is produced when rock materials react with water or substances dissolved within it.
• Erosion: The wear and fragmentation of terrestrial surface materials by water, wind, and other agents. The fragments that emerge are called debris.
• Transportation: The removal of debris from one place to another.
• Sedimentation: The deposition of transported sediments. When these sediments are cemented, they originate sedimentary rocks.

Soils can also be destroyed by heavy rains.

Soil Formation

Soil can form and evolve from most rocky materials, provided they remain in one position long enough to allow the necessary stages of development. Two types can be distinguished:

• Native soils: Formed from in situ alteration of the rock beneath them.
• Allochthonous soils: Formed from materials transported from separate locations. These are mainly found in valley bottoms where the mineral matrix comes from hillside erosion.

Composition

The components of the land can be divided into solids, liquids, and gases.

Importance of Soil

Soil is of great importance because it intervenes in the water cycle and the cycles of elements. It is where much of the energy and matter transformations of ecosystems take place. Furthermore, as its regeneration is very slow, soil should be considered a nonrenewable resource and increasingly scarce, as it is subjected to constant degradation and destruction.