Soil Dynamics: Composition, Properties, and Factors

Soil Dynamics: Composition, Properties, and Influencing Factors

Soil Composition

Soil is a dynamic system influenced by various factors, including temperature, water, plants, wind, and animals. Its composition typically consists of:

• Water: Approximately 25%
• Air: Approximately 25%
• Minerals: 45-50%
• Organic Matter: 0.5-5%

Soil Profile

A soil profile represents the different horizons observed in a horizontal section of soil.

• Eluvial Horizon: Materials are transported from horizon A to horizon B.
• Illuvial Horizon: Horizon B accumulates materials received from the eluvial horizon.

Soil Texture

Soil texture refers to the characteristics of soil that depend on particle size. It is determined by the proportions of different-sized particles.

Soil Structure

Soil structure describes how the various soil components are grouped and combined.

Elements of Soil Texture

• Coarse Soil
• Fine Soil

Soil Density

• Real Density: Calculated by excluding pore spaces.
• Apparent Density: Calculated without excluding pore spaces.

Soil Permeability

Soil permeability is the speed at which water infiltrates saturated soil.

Clay-Humic Complex

The junction of clay and humus colloids forms the clay-humic complex.

• Adsorbent Clay-Humic Power: This term refers to the ability of the negatively charged clay-humic complex to retain cations.

Cation Exchange Capacity (CEC)

CEC is the soil's ability to retain cations and release them into the soil solution. It is expressed in milliequivalents (meq).

Retained Cations

Retained cations influence soil acidity. Acidic ion generators lower the pH, while basic ion generators raise the pH.

Electrical Conductivity

Electrical conductivity is the soil's ability to conduct electricity through salts. The unit of measurement is dS/m.

Soil pH

Soil pH is the negative logarithm of the concentration of hydrogen (H+) protons in the soil solution. Soil pH can be classified as acidic, slightly acidic, neutral, alkaline, or basic.