Diversity

Diversity is defined as the state of being diverse, having a variety. Diversity is apparent in many aspects of soil. Two examples of soil diversity are the different soil orders and the soil biodiversity.

Soil Orders in the United States

The United States exhibits a vast array of soil orders, as shown in the image above. The soil orders included in this map are: Alfisols, Andisols, Aridsols, Entisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, and Vertisols.

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Alfisols are soils that have B horizons enriched with clay that have a base saturation over 35 percent. 
Andisols are soils that are made from parent materials that are volcanic with unique chemical properties. 
Aridsols are soils in arid climates that have visible chemical/weathering alteration. 
Entisols lack development of Soil Horizons.

Histosols are soils that are mainly composed of organic materials. Inceptisols are freely draining soils soils that exhibit minimal development of horizons. Mollisols have a base saturation over 50 percent and have significant accumulation of organic C. Oxisols are located in the tropics and are highly chemically altered. Spodosols are coarse-textured soils located in northern latitude forests. The Fe and Al compounds in this soil have a strong geochemical separation. Ultisols occur in warm, humid climates and have clay-enriched B horizons. Vertisols exhibit a shrink-swell behavior and have a high concentration of silicate clay. Below is a picture of the different soil orders.

Soil Biodiversity

Soil biodiversity refers to the diversity of living organisms in the soil. The most biologically diverse part of the earth is the soil. The soil has a vast biological web of interactions between organisms, plants, and small animals. Bacteria, fungi, worms, spiders, springtails, ants, and countless other organisms make up the diversity of the soil. These organisms are important to the flow of nutrients through the soil. Below is a picture of a

Citations

1 - Amundson, R., Guo, Y. & Gong, P. Ecosystems (2003) 6: 470.

2 - Bailey, Robert G. Description of the ecoregions of the United States. U.S. Dept. of Agriculture, Forest Service, 1995

3 - Guo, Yinyan, et al. “Pedodiversity in the United States of America.” Geoderma, vol. 117, no. 1-2, 2003, pp. 99–115.