Soil as a living and changing material
Soil is the material near the land surface in which mineral particles, organic matter, water, air, and living organisms interact. It is not simply broken rock or a uniform layer of brown material. Soils differ in texture, colour, depth, and structure. These differences develop through combinations of parent material, climate, vegetation, terrain, organisms, and the amount of time during which the ground has been changing. Mineral particles are often described by their sizes. Sand, silt, and clay contribute different properties to the mixture. The spaces between particles and groups of...