Physical Geography — Soil, Vegetation, & Natural Systems

Soil Composition

Soil is a combination of four main ingredients: Parent Material (minerals), Humus (organic matter), Air, and Moisture (water).

Humus

Decayed organic plant and animal matter that provides crucial nutrients for soil.

Soil Horizon

A distinct layer of soil within a soil profile. The top layer (A horizon) contains the highest concentration of humus.

Weathering & Erosion

The natural processes that break down parent material (rocks) into smaller particles like sand, silt, or clay.

Leaching

The downward movement of water through soil in wet climates. As water moves down, it dissolves and carries away essential plant nutrients.

Calcification

The upward movement of water through soil in dry climates. Water evaporates at the surface, leaving behind a thick layer of calcium and minerals.

Permafrost

Ground that remains permanently frozen for two or more consecutive years, typically found in the Arctic Tundra.

Deciduous Trees

Broad-leaved trees (e.g., maple, oak) that shed their leaves in the winter and require warmer temperatures to survive.

Coniferous Trees

Needle-leaved trees (e.g., pine, spruce) that have cones, do not shed their needles, and can survive cold, harsh winters.

Climate Change

Soil acts as a "carbon sink," storing carbon dioxide and preventing it from entering the atmosphere.

Food Security

Proper management of soil allows farmers to grow more food using less land and water.

Ecosystems

Soil filters groundwater and supplies essential nutrients to sustain plant life.