Subcategories

   

 

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

Parent material

Mineral or rock material on and/or from which soils are formed during pedogenesis (soil formation process); parent material is one of the five major soil forming factors.

Partial productivity

Productivity as a result of a single input factor.

Pasture

Grassland used for grazing of mainly domestic herbivores.

Peat

Organic soil material with more than 50% of organic matter derived from plant residues with not fully destroyed structure. Peat forms in a wet soil environment or below the water table where mineralisation of organic matter comes close to zero; a peat horizon or layer is normally more than 30cm thick.

Peatland

A generic term for any wetland where partially decayed plant matter accumulates; mire, moor and muskeg are terms used for peatlands in Europe and Canada; see also bog and fen.

Ped

An individual natural soil aggregate, in contrast to a clod caused by disturbance, or a concretion caused by cementation. Described as a range of shapes: platy (laminated), prismatic (vertical axis of aggregates longer than horizontal), columnar (prisms with rounded tops), blocky (angular or subangular) and granular.

Pedo-climatic zone

Zones that are relatively homogeneous concerning climate and soil (e.g., Metzger et al., 2005).

Pedogenesis

Process of soil formation and development by soil forming factors: climate (mainly temperature and precipitation), parent material, living organisms (plants and biota), topography, time, water and Man.

Pedon

The smallest volume that can be called "a soil.'' A pedon is three dimensional and large enough to permit study of all horizons. Its area ranges from about 1 to 10 m2, depending on the variability of the soil.

Pedosphere

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.
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