Types of Soil Worksheet

Alfisols

• Alfisols are highly fertile soils that form in forests and consist of a subsurface of clay. This layer of clay locks in moisture and nutrients. Found primarily in temperate zones, a large strip of Alfisols extends from south Texas through Michigan.

Andisols

• Andisols are formed by volcanoes, and are most often found in the Hawaiian Islands and the Northwest near active and recently active volcanoes. Andisols have a high water-holding capacity due to the glass grains and material with pores that are formed from the ashes and ejecta of volcanic activity.

Aridisols

• Aridosols make up approximately 12 percent of the earth's ice-free land surface and are primarily found in deserts and arid regions, as the name implies. Aridosols contain high concentrations of calcium carbonate, with clay, silica, salt and gypsum.

Entisols

• Entisols are new soils developed from recently deposited parent material, such as in sand dunes, mountain hillsides and riverbanks. These soils make up 16 percent of the earth's ice-free land surface.

Gelisols

• Gelisols are found in locations that have permafrost within 2 meters of the surface. They are often found in higher latitudes and longitudes, and contain a lot of carbon material due to the fact that decomposition is so slow. Nine percent of the earth's ice-free land surface is composed of gelisols.

Histosols

• Histosols have more than 40 centimeters' worth of organic material that's not fully decomposed due to the presence of continual moisture, such as in peats, bogs and swamps. Only 1 percent of the earth's ice-free land surface is composed of histosols.

Inceptisols

• Inceptisols are considered mature versions of entisols. They have very little soil weathering and development indicators, such as soil horizons. They're found all over the world.

Mollisols

• The "breadbasket of the world," the Great Plains region of the United States, consists of mollisols. Highly organic, the grasses in this region have developed a rich, dark-colored surface zone, making them ideal for growing grain crops.

Oxisols

• Oxisols are heavily leached soils due to long-term weathering. Oxisols are low in nutrients, and are often high in aluminum and iron. Only 8 percent of the world's ice-free soils are composed of oxisols.

Spodosols, Ultisols and Vertisols

• Spodosols are acidic and infertile and are often found in heavily forested areas such as the Northeastern United States. Ultisols are similar to spodosols, except for the distinct subsurface clay layer high in iron. These soils are common throughout the Southeastern United States. Vertisols are aptly named for their extreme changes in volume due to water content. They have cracks that open and close periodically and are found in sections of Texas and the Delta region of Mississippi.