0-9   A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Arable land

Agricultural land that is cultivated by ploughing, usually to 20 or 30 cm depth. More than 30 cm represents deep ploughing.

Available water storage capacity

Corresponds to the water retained in the soil between the states of field capacity (FC) and permanent wilting point (PWP)


The diversity of living organisms in any one place.


A soil formation factor that describes living organisms in a particular region and at a particular time. It includes vegetation, microbes, soil animals, and human beings.

Black Earth

Term synonymous with Chernozem used (e.g. in Australia) to describe self-mulching black clays.


Wetland that has no significant inflows or outflows, supports acidophilic mosses, particularly Sphagnum and in which peat is accumulating. Similar to: fen, marsh, pocosin, swamp, and wetland.

Boulder clay

Unstratified glacial deposits laid down directly beneath the ice or dropped from the surface as the ice melted; boulder clay and till are synonymous terms for this unsorted material which ranges from rock flour to rocks and boulders of great size, according to the nature of the bedrock.


Process whereby the soil is kept sufficiently supplied with calcium to saturate the soil cation exchange sites.

Capillary water

Water in capillary pores influenced by forces that hold water in soils against a tension usually greater than 60cm. Capillary water can move upwards against gravity.

Carbon cycle

Sequence of transformations whereby carbon dioxide is converted to organic forms by photosynthesis or chemosynthesis, recycled through the biosphere (with partial incorporation into sediments), and ultimately returned to its original state through respiration or combustion.

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