Soil is not dirt. It is a vital life-support system for human survival. Below are the major functions of soil:
a) Production function. Soil acts primarily as a medium for the growth of natural vegetation and cultivated plants. It assures the supply of food, fodder, renewable energy and raw materials. This is also referred to as the forestry and agricultural function of the soil.
b) Ecological regulator. Soil acts as filter, buffer, and transformer of various substances in or that are added to the soil. As a filter, the soil cleans polluted waters that move through it. As a buffer, it resists sudden change in its chemical balance thereby protecting the plants and soil organisms living in it. As a transformer, the soil is able to transform substances through microbiological and biochemical processes. The latter function is vital to the cycling of elements, degradation of toxic substances, decomposition of organic matter and production of greenhouse gases.
c) Habitat and living space. Soil is a habitat for a multitude of flora and fauna which are vital for human life. The largest quantity of organisms on Earth is in the soil. Many of the important antibiotics to treat human diseases are products of soil bacteria. Thus soil management is directly linked to the question of biodiversity. Soil also provides living space for humans and foundation for indrastructure such as roads, buildings, airports and others. Many human illnesses today are caused by soil pollutants that enter the food chain or enter the body through ingestion or inhalation.
d) Cultural heritage. Soil conceals and preserves remnants of past civilizations and plant and animal life. These paleontological and archaeological materials are of great value for the understanding of the history of civilization and the history of Earth.