Soil

Soil refers to the uppermost layer of the earth's crust which is made up of unconsolidated material formed from the weathering of rock.

Comprises both organic and inorganic matter.

Importance for Soil

Provides mineral nutrients for plant growth

- Allows for economic activity e.g. agriculture.

- Important for plant stabilization

- Provides habitat for organisms.

- Provides water + air for plants roots.

- Cultural and medicinal value.

Soil Properties

1. Soil Profile - A vertical section from the surface to the parent material (bed rock).
2. Soil Texture - Degree of coarseness of the soil.
3. Soil Structure - Arrangement of soil particles (clumped together or individual)
4. Soil Colour - Determined by the minerals in the soil e.g. iron.
5. Soil Porosity - Empty spaces between particles that allow space for water and air.
6. Soil pH - How acidic or alkaline the soil is, based on nutrients in the soil.
7. Soil Depth - How deep the unconsolidated materials go below the surface.
8. Soil Temperature - Warmer temperatures result in an increased rate of recycling of nutrients.

Factors Affecting Soil Formation

• Parent Material
• Climate
• Living Organisms
• Relief
• Time

Latosols

Latosols are tropical zonal soils found in rainforests and savannas, heavily influenced by climate and vegetation. They are inherently infertile due to high rainfall and year-round high temperatures in equatorial regions. Rainfall leaches minerals, while high temperatures accelerate weathering and organic matter decomposition, resulting in a thin humus layer as nutrients are quickly absorbed.

Rendzinas

Rendzinas are intrazonal soils. Intrazonal soils are affected by parental material and drainage. Rendzinas form where the parent rock is limestone. These soils are shallow and nutrient rich.