S2 Biology Notes: Soil – Formation, Profile, Components and Types

These Senior 2 Biology notes are about soil. They explain why soil matters and how physical, chemical and biological weathering form it. They cover the factors that affect soil formation and describe the soil profile with its A, B and C horizons. The notes go through the six soil components: inorganic particles, air, water, humus, mineral salts and living organisms. They include practical experiments to find soil texture and the percentage of air, water and humus in soil, and to show that living organisms are present. There are worked calculations and short exercises. Later sections cover what affects soil quality, culture solutions, and how sandy, clay and loam soils compare.