soil

soil system

a dynamic system with inputs, outputs, storages, transfers, and transformations of matter and energy

humus

Relatively stable, dark organic matter formed by the decomposition of dead organisms; it helps soil retain water and nutrients.

soil horizon

A distinct layer within a soil profile, formed by processes such as decomposition, leaching and the accumulation of materials.

soil texture

The relative proportions of sand, silt and clay particles in soil, influencing drainage, aeration and water retention.

loam

Soil containing a balanced mixture of sand, silt and clay, often with favourable conditions for plant growth.

leaching

The movement of dissolved nutrients and minerals down through soil as water percolates through it.

soil carbon sink

A soil system that absorbs and stores more carbon than it releases over a given period.

soil carbon source

A soil system that releases more carbon into the atmosphere than it absorbs over a given period.

soil organic matter (SOM)

The organic material in soil, including decomposing remains and humus, that contributes to nutrient cycling, soil structure and water retention

food security

A condition in which all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food.

food sovereignty

The principle that people and communities should have control over their food systems, including how food is produced and distributed

green revolution

The expansion of agricultural production through high-yielding crop varieties, irrigation, synthetic fertilisers and pesticides, particularly from the mid-20th century

intensive agriculture

Farming that uses high inputs of labour, capital, fertilisers, pesticides or technology per unit of land to increase production.

extensive agriculture

Farming that generally uses lower inputs per unit of land and relies on larger areas to produce food.

monoculture

The cultivation of a single crop species over a large area, often repeatedly, which can increase vulnerability to pests and reduce biodiversity.

synthetic fertiliser

A manufactured source of plant nutrients, such as nitrogen, phosphorus and potassium, used to increase crop growth and yields

agricultural energy ratio

The ratio of energy contained in the food produced to the energy invested in producing it. A higher ratio indicates greater energy efficiency

trophic-level energy transfer

The transfer of energy between feeding levels in a food chain; much energy is lost through respiration, heat and waste rather than becoming new biomass

sustainable diet

A dietary pattern with relatively low environmental impacts that supports food security and nutrition while remaining socially and economically viable

soil degradation

A decline in soil quality and function that reduces its capacity to support ecosystems and agriculture

soil erosion

The removal and transport of topsoil by agents such as water and wind, often accelerated by vegetation removal and poor farming practices.

salinisation

The accumulation of soluble salts in soil, often caused by irrigation and evaporation in areas with insufficient drainage.

desertification

Land degradation in arid, semi-arid and dry sub-humid regions resulting from climatic variations and human activities.

soil compaction

The compression of soil particles, reducing pore space and restricting water infiltration, aeration and root growth

crop rotation

Growing different crops in sequence on the same land to help maintain soil fertility and interrupt pest and disease cycles.

intercropping

Growing two or more crop species together in the same field to use resources more effectively and potentially reduce pest pressure

agroforestry

Integrating trees or shrubs with crops and/or livestock to provide ecological and productive benefits.

contour ploughing

Ploughing along the contours of sloping land to slow surface runoff and reduce soil erosion

terracing

Creating a series of level or gently sloping platforms on hillsides to reduce runoff and soil loss and support cultivation.