Nice collection of information about US types of soil

People describe soil types in all kinds of ways such as heavy, light, sandy, clay, loam, poor or good.

Soil makes up the outermost layer of our planet.

Soil scientists describe soil types by how much sand, silt and clay are present. This is called texture.

Soil is formed from rocks and decaying plants and animals.

An average soil sample is 45 percent minerals, 25 percent water, 25 percent air, and five percent organic matter.

Soils are formed under the influence of climate, the material they occur on, the flora and fauna (including human activity), the topography of the terrain, and time. These five factors are commonly known as the Soil forming factors.

Because soil is important for cultivation and agricultural production, soil fertility and productivity are important issues to address. Detailed pedological knowledge is useful for land evaluation purposes, i.e. the classification in fertile productive soils and less valuable soils. Soils are an integral part of landscapes and the knowledge of the distribution of different soils helps to preserve a high standard in environmental quality. For example, site specific management cannot be developed without detailed knowledge of soils. Critical sites, e.g. shallow hillslope soils prone to erosion and leaching of nutrients, can be identified using pedology. Soil surveys furnish basic inputs to soil conservation planning and provide information used in equations for predicting soil loss and water pollution under various management practices on different soils.