Lab 4 Part 2 - Soil Orders of the World

The different soils of the world are classified into twelve types, or orders, which are:

• Gelisols
• Histosols
• Spodosols
• Andisols
• Oxisols
• Vertisols
• Aridisols
• Ultisols
• Alfisols
• Inceptisols
• Entisols

Besides the soil order discussed below, more information on all of these soil orders can be found at: Soil Taxonomy

Andisols -
Andisols are formed from volcanic material (mainly ash), and contain a large quantity of glassy material (also volcanic). Because they form only in volcanic environments, andisols are not very common. The photo below shows the worldwide distribution of andisols.

Andisols are usually young, very fertile soils that have unique physical properties including the capacity to hold a large of amount of water. Another interesting property is the andisols ability to retain more phosphorous than usual in the soil, making it unavaible to plants. Andisols are further divided up into eight sub-orders, which are listed and briefly described here. Because of their fertility, andisols often support intensive farming for crops such as coffee, tea, and fruit. A profile of an andisol is shown below with measurements.