Structure (pedology)
The structure is in Pédologie the way according to which arranges itself naturally and durably the elementary particles by forming or not Agrégat S.
The aggregate is the result of the natural organization of the components, it in what it is basically different from a fragment which results from the crack of a preexistent object. All the mechanisms and processes of the pedogenesis (physical, chemical and biological actions) contribute to transform materials with lithological structure (rock and deposits) into materials with pedological structure .
Great types of structures are preset:
No visible aggregation nor provision ordered and defined around the natural lines of weak résitance.
- lithic Structure or lithological
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Absence of aggregates, nonpedological structures inherited the bed rock.
Absence of aggregates, coherent horizon, being able to be more or less hardened by cements.
Absence of aggregates, non-cohesive horizon, made up of particles (mineral or organic) individualized and free.
Aggregates with forms definitely round, more or less spherical, little or not porous, with curved faces, without edges nor preferential orientation.
Aggregates with definitely round forms, porous, presenting a unit complexes dominant curved faces and plane faces on irregular surfaces; irregular and mamelonnés aggregates; these “grumeaux” is often more or less agglomerated between them.
friable Structure whose elements have a dimension lower than the millimetre.
Aggregates with definitely angular edges and/or plane faces, with horizontal preferential orientation, in general much broader than thick.
Aggregates with definitely angular edges and/or plane faces, lengthened according to a vertical preferential orientation.
prismatic Structure at round top.
Aggregates with plane faces clear and very few, edges (vertical and horizontal) sharp and all appreciably of the same dimension.
preferential Orientation obliques (neither vertical, nor horizontal); faces generally plane, sometimes warped, almost always smooth and often striated; arrises.
Aggregates without preferential orientation, plane faces, angular edges and sharp.
Aggregates with several types of faces or edges, or with badly defined forms, often blunted edges.
Material especially made up of fibrous organic residues (foams, ferns).
Material mainly made up of globular millimetre-length clusters (dejection of the mésofaune of the ground) more or less altered but always individualized.