Soils are composed of solid mineral particles, organic matter, humus, living roots and organisms, and spaces holding air and water (pores). Soil is one of Virginia’s basic natural resources. We are dependent upon the soil as a primary resource of supporting food, fuel, and fiber production. Soils supply nutrients (elements or compounds) necessary for vigorous plant growth for plant growth. Soil moisture affects air pollution and vegetation cover that prevents erosion. Soils are necessary as a base for buildings and roads. Most new houses rely on onsite septic system drain fields to dispose of and treat septic waste through the soil nearby. Soils store carbon and water, clean the water of pollutants and excess nutrients, provide a rooting zone and structural support for plants, and offer habitat to microbes and animals.