Soil is composed of rock and mineral particles; decaying plants and animals; living plants and animals; and water and air. Plant roots work their way between the soil particles, binding and aerating the soil.
Soil forms slowly, taking from 50 to more than 1,000 years to build up a thin layer. The process of destruction as a result of misuse or erosion is much quicker. Once completely destroyed, soil is for all practical purposes lost for ever.