IB Environmental Systems: Soil & Terrestrial Systems Revision

Soil & Terrestrial Systems is a core part of IB Environmental Systems. Revise the key concepts and common mistakes below, then lock them in with the free games.

Key concepts

Soil horizonsLayers O, A, B, C, R from organic litter to bedrock; differ in colour, texture, composition.

Soil texture triangleClassifies soils by % sand, silt, clay; loam is balanced and most productive (USDA classification).

Green Revolution1940s-70s adoption of high-yield varieties, fertilisers, irrigation; Borlaug Nobel 1970.

SalinisationSalt build-up in irrigated soils; reduces yield; estimated to affect over 60 million hectares globally.

Industrial agricultureMechanised monocultures, synthetic inputs; high yield but high fossil fuel and water use.

Food securityReliable physical, social, economic access to sufficient safe nutritious food (FAO 1996 definition).

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Soil & Terrestrial Systems

Key concepts

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