Volcanic materials of soil

Volcanic materials

Volcanic soils are developed from volcanic materials, which have a glassy, or non-crystalline, structure. As a result, volcanic soils largely consist of amorphous materials that lack a crystalline structure.

Three types of identifies amorphous minerals in volcanic soils:

• Allophone
• Imogolite
• Ferrihydride

On Maui, most volcanic soils consist of materials that are indistinguishable.

Amorphous materials generally have a great surface area; and so, they may absorb a lot of water. However, due to its high AEC, amorphous materials have a low ability to retain and supply nutrients under acidic conditions.

CATION EXCHANGE CAPACITY OR ANION EXCHANGE CAPACITY?

Amorphous materials have a high AEC under acidic conditions.

MANAGEMENT

The ability to supply nutrients can be improved in soils containing amorphous materials through the addition of organic matter. Since organic matter has a large CEC under most soil conditions, additions of organic matter enhances the CEC of the soil.