Solum

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Solum and soils are not synonymous. Some soils include layers that are not affected by soil formation. These layers are not part of the solum. The number of genetic horizons ranges from one to many. A surface layer that is 10 cm thick overlying bedrock can be by itself the solum. A soil that consists only of recently deposited alluvium or recently exposed soft sediment does not have a solum.

In terms of soil horizon designations, a solum consists of A, E, and B horizons and their transitional horizons and some O horizons. Included are horizons with an accumulation of carbonates or more soluble salts if they are either within, or contiguous, to other genetic horizons and are at least partly produced in the same period of soil formation. The solum of a soil presently at the surface, for example, includes all horizons now forming. The solum of a soil is not necessarily confined to the zone of major biological activity. A solum does not have a maximum or a minimum thickness.

The lower limit should relate to the depth of rooting to be expected for perennial plants assuming that soil moisture conditions and soil chemistry are not limiting. In some soils the lower limit of the solum can be set only arbitrarily and needs to be defined in relation to the particular soil. For example, horizons of carbonate accumulation are easily visualized as part of the solum in many soils in arid and semiarid environments. To conceive of hardened carbonate accumulations extending for 5 meters or more below the B horizon as part of the solum is more difficult. Gleyed soil material begins in some soils a few centimeters below the surface and continues practically unchanged to a depth of many meters. Gleying immediately below the A horizon is likely to be related to the processes of soil formation in the modern soil. At great depth, gleying is likely to be relict or related to processes that are more geological than pedological. Much the same kind of problem exists in some deeply weathered soils in which the deepest material penetrated by roots is very similar to the weathered material at much greater depth. [cite web | url = http://soils.usda.gov/technical/manual/print_version/complete.html | title = Soil Survey Manual | author = Soil Survey Staff | date = 1993 | publisher = Soil Conservation Service. U.S. Department of Agriculture Handbook 18. | accessdate = 2006-07-02]

References


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Look at other dictionaries:

  • şolum — şolúm, şolúmi, s.m. (reg.) persoană şchioapă; şchiop. Trimis de blaurb, 14.02.2007. Sursa: DAR …   Dicționar Român

  • solum — Latin, “ground, soil,” of unknown origin …   Etymology dictionary

  • solum — [sō′ləm] n. pl. solums or sola [sō′lə] [ModL < L, base, soil] the altered soil or material overlying the parent material, often including the A horizon and the B horizon …   English World dictionary

  • Solum — Profil de sol Les différents horizons d un profil de sol Le profil de sol est l ensemble des horizons d un sol donné ; chaque horizon étant une couche repérable et distincte de ce sol. On parle aussi de solum ou des horizons du sol. Ces… …   Wikipédia en Français

  • Solum — Das Solum (lat. Boden) ist ein Begriff aus der Bodenkunde und bezeichnet einen Bodenkörper ohne die Streuschicht (L) und das Ausgangsgestein (C) mit einzubeziehen. Werden diese mit einbezogen, spricht man vom Pedon. Literatur Blum, Winfried E.H.; …   Deutsch Wikipedia

  • solum — so̱lum [lat.]: Adverb mit der Bedeutung „nur, ausschließlich“; z. B. in der Fügung ↑Albinismus solum bulbi …   Das Wörterbuch medizinischer Fachausdrücke

  • solum — /ˈsoʊləm/ (say sohluhm) noun (plural solums or sola / la/) the upper layers of a soil profile in which topsoil formation occurs in response to climate and vegetation. {New Latin, from Latin solum ground} …   Australian English dictionary

  • solum — noun (plural sola or solums) Etymology: New Latin, from Latin, ground, soil Date: 1928 the altered layer of soil above the parent material that includes the A and B horizons …   New Collegiate Dictionary

  • solum — /soh leuhm/, n., pl. sola / leuh/, solums. the upper part of the soil profile, which is influenced by plant roots; the A horizon and the B horizon. [1820 30; < L: base, bottom; see SOLE2] * * * …   Universalium

  • solum — noun Within a soil profile, a set of related soil horizons that share the same cycle of pedogenic processes …   Wiktionary

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