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Soils of the World

Themes: Soil classification | Climate influenced soils | Other worldwide soils | Quiz

Soils form through a combination of influences, the most important of which are parent rock, climate, relief, vegetation and organisms, time and the influence of human beings over the centuries. This combination of influences varies greatly throughout the world so it should not be a surprise that there are many thousands of different soils in the world. Just as the members of the plant and animal kingdom have been classified, there have been several attempts in the past 150 years to classify soils and give names to them.

Unlike plants and animals, which are discrete entities and have recognisable features on which to base their classification, the classification of soils is much more complex because soils are a continuum across the landscape and grade into one another. Furthermore the features and characteristics of the soil which need to be used in classification are mainly below ground and largely out of sight unless you dig a hole. Soil classification has thus been difficult and remains so.

There have been three major classifications of world soils: the US Soil Taxonomy, the Food and Agriculture Organisation (FAO) classification, and more recently the FAO-UNESCO World Reference Base (WRB) for Soil Resources. Rather than make things complicated for you with the difficult terminology of these soil classifications, we shall take a simpler look at how soils are distributed around the world. We shall also give some examples of where factors such as relief, geology and human activity have been a stronger influence on world soils than that of climate.

Themes: Soil classification | Climate influenced soils | Other worldwide soils | Quiz