Soil Formation

Soil Texture

Refers to the feel, appearance, and consistency of soil.

Soil Structure

Refers to the clumping of the textural components in soil.

Porosity

A measure of the porous space in a material.

Soil Colour

Refers to the different colours of the soil horizons.

Humus

The part of the soil made up of dead plants and animals.

Rock Pieces in Soil

The three main kinds are sand, silt, and clay.

Sand

Loose material that does not hold water well.

Silt

Holds water but is light and can be easily blown away.

Clay

Holds water but is heavy and may not be ideal for growing.

Loam

A mixture of sand, silt, and clay, considered the best for growing.

Fertile Soil

A mixture of minerals, air, water, and organic matter in correct proportions.

Pedology

The study of soil as a geological entity.

Edaphology

The study of soil as a habitat for living organisms.

Stages of Soil Formation

Includes disintegrating rock, early soil development, formation of A horizon, and development of B horizon.

C Horizon

Consists of partially weathered parent material.

A Horizon (Topsoil)

The most fertile layer, vital for plant life, with dark organic material mixed with minerals.

B Horizon (Subsoil)

Accumulation of materials from above, often more compact with less organic material.

O Horizon (Organic Layer)

Mostly composed of organic material (humus), often absent in many soils.

Factors Affecting Soil Formation

Includes parent material, time, climate, organisms, and topography.

Soil Horizons

Layers in the soil, including O, A, B, and C horizons.

Weathering

Different agents that affect soil formation.

Soil Textural Triangle

A diagram used to classify soil texture based on the percentages of sand, silt, and clay.

Soil's Water-Holding Capacity

Understanding this helps determine the suitability of soil for different crops.

Subsoil

Contains accumulated materials like clay and iron, different from the topsoil.

Organic Material in A Horizon

Mixed with minerals, contributes to the dark color of the topsoil.

Weathered Parent Material

The composition of the C horizon, the lowest soil layer.