Soil Formation Factors and Altitudinal Vegetation

Soil Formation Factors

Parent Rock (Roca Madre): This is the mineral substrate from which soil is formed. It affects its color, texture, structure, permeability, and acidity.

Climate: This is the most influential factor. Temperatures affect chemical and biological processes, while rainfall conditions the leaching process.

Topography: Heavy soils accumulate in flat areas, while steep slopes lead to erosion and soil slippage.

Living Beings: These act in various ways. Various plants may acidify the soil, impoverish it, or enrich it by providing a base or picking up nutrients through their roots.

Time: This is a determinant factor, since the formation of a soil is a slow process that requires centuries.

Soil Horizons and Profiles

Soils are made of horizons or layers identified by their physical, chemical, and biological properties. The whole set of horizons is the soil profile.

• In Depth: The deepest horizons are identified as D and C.
• Surface: This is the A horizon. It includes a layer formed by litter (A0), a layer consisting of dark humus (A1), and a clearer layer (A2), which is a zone of leaching or loss of substances that are washed by rainfall to the lower layers.
• Horizon B: Situated between both, it has a more intense color. It contains a layer of alteration in contact with the C horizon and a layer of accumulation of substances leached from the A horizon.

Key Soil Terminology

• Soil Texture: The size of the particles that compose the soil.
• Structure: How the particles are grouped into larger soil fragments.
• Permeability: The capacity of soils to allow water and gas filtration.
• Leaching: The process of moving soluble materials from the soil surface horizons to deeper horizons through rainwater.
• Horizons: Layers identified by their physical, chemical, and biological characteristics.
• Profile: A set of horizons.
• Rankers: Soils on rocky areas that are located in siliceous higher areas or slopes.
• Azonal Soils: Soils that lack a well-defined profile because they are young or located on slopes that are too steep.
• Intrazonal Soils: Soils with a defined profile that contrasts with the surrounding ground due to the influence of local factors other than climate.

Understanding the Cliserie

A cliserie is a graph showing the distribution of vegetation as a function of height. The causes of climatic variations are staggered, caused by the progressive increment of altitude. Temperatures decrease on average by 0.5°C or 0.6°C per 100 meters of ascent, and precipitation increases due to the cooling of the air. The result is a staggering of climate from the base to the summit, following an escalation of the vegetation.