soil

A Horizon (Topsoil)

Upper soil layer rich in organic matter, nutrients, and air; best layer for plant growth.

Soil Profile

The complete vertical arrangement of soil horizons (layers).

Humus

Dark, decomposed organic matter that improves soil fertility and water retention.

Weathering

The breakdown of rocks into smaller particles by physical, chemical, or biological processes.

Leaching

The removal of dissolved nutrients and minerals from soil by water.

Infiltration

The movement of water from the surface into the soil.

Percolation

The downward movement of water through soil layers.

Salinisation

The buildup of salts in soil, often caused by irrigation and high evaporation.

Clay

The smallest soil particle; holds water and nutrients very well.

CEC (Cation Exchange Capacity)

A soil’s ability to hold and exchange nutrient ions for plant use.

Nutrient Cycling

The movement and recycling of nutrients through an ecosystem.

Crop Rotation

Growing different crops on the same land in succession to maintain soil fertility.

Monoculture

The cultivation of a single crop over a large area.

Commercial Farming

Farming done primarily to produce crops or livestock for sale and profit.

Subsistence Farming

Farming that produces enough food mainly for the farmer and their family.

Permaculture

A sustainable farming system designed to mimic natural ecosystems.

Regenerative Farming

Farming practices that restore soil health, biodiversity, and ecosystem function.

Food Security

Reliable access to enough safe and nutritious food.

Carrying Capacity

The maximum population an environment can sustainably support.

Liming

The addition of lime to soil to increase pH and reduce acidity.

Contour Ploughing

Ploughing across a slope rather than up and down to reduce erosion.

Terracing

Creating step-like levels on hillsides to increase farmland and reduce erosion.

Trickle Irrigation (Drip Irrigation)

A method of slowly delivering water directly to plant roots.

Biodiversity

The variety of living organisms within an ecosystem.

Sustainable Agriculture

Farming that meets present food needs without harming future generations’ ability to meet theirs.

O Horizon

Surface layer made mostly of dead leaves, twigs, and other organic matter.

E Horizon

Leached layer where minerals, clay, and nutrients have been washed out; usually lighter in color.

B Horizon (Subsoil)

Layer where minerals, clay, iron, and nutrients accumulate from above.

C Horizon

Partially weathered parent material with very little organic matter.

R Horizon (Bedrock)

Solid rock beneath the soil profile from which the soil develops.