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Soil (the pedosphere) represents the critical zone of the earth where life (the biosphere), water (the hydrosphere), minerals (the lithosphere), and air (the atmosphere) intersect and interact.

Pedotransfer function (PTF)

A mathematical relationship between two or more soil properties that shows a reasonably high level of statistical confidence. PTF

Penetration resistance or penetrability

The ease with which a probe can be pushed into the soil.


Pertaining to processes, conditions, areas, climates and topographic features occurring at the immediate margins of glaciers and ice sheets and influenced by cold temperature of the ice.


(i) permanently frozen subsurface material underlying the solum; (ii) perennially frozen soil horizon where temperature remains below 0

Permanent grassland

Natural (mainly steppe areas) or agricultural soils with grass cover not normally ploughed.


The quality of the soil that enables water (or fluids or plant roots) to move downward through the profile. Permeability is measured as the distance per unit time that water moves downward through the saturated soil. Terms describing permeability are: very slow: <0.15 cm/hr, slow: 0.15-0.5 cm/hr, moderately slow: 0.15-1.5 cm/hr, moderate: 1.5-5 cm/hr, moderately rapid: 5-15 cm/hr, rapid: 15-50 cm/hr, rapid: > 50 cm/hr.

Pest management

The way in which pests are controlled.


Synthetic biocide directed at destroying insects, nematodes, molluscs, mammals, plants, fungi or bacteria.


Measure of acidity, measured from 1 (acid) through 7 (neutral) to 14 (alkaline) expressed on a logarithmic scale. Most soils have a pH 3 to 9.

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