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an effect, and hard acidic rocks give rise to more acidic soils than do the softer sandstones. The landscapes where these lowland soils occur are typically undulating, and interesting variations in the profiles relate to the slopes where they are found. We think, perhaps of soils as static and unchanging, but in fact they are never stationary. The processes of weathering and plant growth that were responsible for the formation of soils from bare parent materials in the first place are still going on. This is most easily seen on a hill slope. The top of the hill is usually convex, and it is here that most erosion is taking place – upper slopes and summits are more exposed to wind, and rain, and gravity is slowly but surely moving the topsoil down the hill. Thus soils on the brow of the hill tend to be shallower than those in mid-slope positions, where soil is moving down, but being replaced by material from above. At the base of the slope we usually find a concave area where the eroded soil has accumulated. Here the topsoils will be significantly thicker than elsewhere.
205:(well decomposed alkaline organic matter) and mineral matter. It is biologically active with many soil organisms and plant roots mixing the mull humus with mineral particles. As a result, the boundary between the A and B horizons can be ill-defined in unploughed examples. Horizon B is mostly composed of mineral matter which has been weathered from the parent material, but it often contains inclusions of more organic material carried in by organisms, especially earthworms. It is lighter in colour than the A horizon, and is often weakly illuviated (enriched with material from overlying horizons). Due to limited leaching only the more soluble bases are moved down through the profile. Horizon C is made up of the parent material, which is generally
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in the WRB. These are rather similar to brown earths, and some other classifications, including the
British and French, call these soils argillic brown earths (sol brun lessive), because they have an argillic, i.e. clay-enriched horizon at some depth well below the A horizon. The argillic character
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in the topsoil tends to be higher (more alkaline) than in the subsoil as a result of the addition of lime over the years. In general, the wetter the climate, the more acidic the soils. This is because rain tends to wash the "alkaline" bases out of the soil. Of course, the parent material also has
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Brown earths are important, because they are permeable and usually easy to work throughout the year, so they are valued for agriculture. They also support a much wider range of forest trees than can be found on wetter land. They are freely drained soils with well-developed A and B horizons. They
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soil. Brown earths are also classified in the German and
Austrian soil taxonomy as "Braunerde." Braunerden are widespread and frequently occur on unconsolidated parent sand or loess parent materials. "Parabraunerde" is the classification for a brown earth with an eluvial horizon above a slightly
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woodland and grassland. Due to the reasonable natural fertility of brown earths, large tracts of deciduous woodland have been cut down and the land is now used for farming. They are normally located in regions with a humid temperate climate.
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soils in which there is an orange-brown B horizon, but no pale leached horizon between the A and the B horizons. These are called
Umbrisols in the WRB, and are particularly common in western Europe, covering large areas in NW Spain.
240:. The rich colour is the result of iron compounds, mainly complex oxides which, like rust, have a reddish-brown colour. Some of these soils are, in fact, red. For example, in Great Britain reddish brown earths occur on the
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Typically the brown earths have dark brown topsoils with loamy particle size-classes and good structure – especially under grassland. The B horizon lacks the grey colours and mottles characteristic of
288:. In France they have been included with "sol brun acide", although these soils may tend to have more iron and aluminium in the B horizon, and tend to what, in the British classification, is called a
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argillic, clayey illuvial horizon. This gives rise to a universal division of these, generally brown and well drained soils into the weakly leached brown earths - called
256:), and are red because the rocks from which they formed are derived from strongly oxidised deposits that were laid down under desert conditions millions of years ago.
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totals are moderate, usually below 76 cm per year, and temperatures range from 4 °C in the winter to 18 °C in the summer. They are well-drained fertile
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of the UK, and the differences between brown earths proper (cambic brown earths) and argillic yellow earths are not apparent to the general observer.
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A brown earth soil is affected by several different factors. These include: climate, relief, soil drainage, parent material and the
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176:. They are common in lowland areas (below 1,000 feet) on permeable parent material. The most common vegetation types are
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201:: the A, B and C horizon. Horizon A is usually a brownish colour, and over 20 cm in depth. It is composed of mull
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often develop over relatively permeable bedrock of some kind, but are also found over unconsolidated
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140:. The largest expanses cover western and central Europe, large areas of western and trans-Uralian
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and eastern Asia. Here, areas of brown earth soil types are found particularly in
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Brown earths have a long history of being a major grouping in most
136:. Brown earths are mostly located between 35° and 55° north of the
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include well-drained alluvial soils in the brown earths too.
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367:. European Soil Bureau Network, European Commission.
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46:. Unsourced material may be challenged and removed.
363:Jones, A.; Montanarella, L.; Jones, R. (2009).
209:and non- or slightly acidic, for example clay
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106:Learn how and when to remove this message
168:. Brown earths cover 45% of the land in
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299:World Reference Base for Soil Resources
703:Canadian system of soil classification
342:World reference base for soil fertile
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44:adding citations to reliable sources
217:General relations in western Europe
687:Unified Soil Classification System
318:is rather weakly expressed in the
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692:AASHTO Soil Classification System
345:. Cambridge University Department
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309:Further east in Europe, in more
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31:needs additional citations for
708:Australian Soil Classification
699:(French classification system)
276:that live in the soil itself.
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259:In long-cultivated soils the
728:List of vineyard soil types
197:Soils generally have three
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713:Polish Soil Classification
228:like river gravels. Some
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737:Non-systematic soil types
723:List of U.S. state soils
301:(WRB); and more leached
189:of between 5.0 and 6.5.
718:1938 USDA soil taxonomy
697:Référentiel pédologique
681:FAO soil classification
339:Bridges, E. M. (1997).
382:definition of argillic
268:Soil formation factors
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297:in the international
146:east coast of America
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849:Calcareous grassland
426:World Reference Base
365:Soil Atlas of Europe
311:continental climates
286:soil classifications
230:soil classifications
193:Horizontal structure
40:improve this article
418:Soil classification
602:USDA soil taxonomy
428:for Soil Resources
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1001:
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250:New Red Sandstone
242:Old Red Sandstone
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889:Hydrophobic soil
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376:External links
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303:brown podzolic
290:brown podzolic
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280:Classification
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132:is a type of
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57: –
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55:"Brown earth"
52:
51:Find sources:
45:
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35:
34:
29:This article
27:
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18:
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904:Martian soil
843:
364:
358:
347:. Retrieved
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129:
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62:
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38:Please help
33:verification
30:
969:Terra rossa
964:Terra preta
944:Spodic soil
864:Duplex soil
844:Brown earth
824:Alkali soil
814:Rhizosphere
809:Laimosphere
683:(1974–1998)
640:Inceptisols
547:Plinthosols
512:Kastanozems
166:New Zealand
130:Brown earth
1008:Categories
949:Stagnogley
899:Lunar soil
854:Dark earth
839:Brickearth
804:Pedosphere
774:Soil crust
582:Technosols
567:Solonchaks
487:Ferralsols
452:Anthrosols
349:2006-06-09
326:References
274:soil biota
248:) and the
238:gley soils
160:, eastern
125:Brown soil
96:March 2022
66:newspapers
934:Quicksand
879:Fill dirt
819:Bulk soil
665:Vertisols
655:Spodosols
645:Mollisols
635:Histosols
620:Aridisols
592:Vertisols
587:Umbrisols
577:Stagnosol
542:Planosols
537:Phaeozems
517:Leptosols
502:Gypsisols
492:Fluvisols
472:Chernozem
467:Cambisols
462:Calcisols
457:Arenosols
295:cambisols
207:permeable
178:deciduous
162:Australia
118:Soil type
1014:Pedology
919:Paleosol
834:Blue goo
789:Gypcrust
660:Ultisols
630:Gelisols
625:Entisols
615:Andisols
610:Alfisols
572:Solonetz
562:Retisols
557:Regosols
532:Nitisols
527:Luvisols
522:Lixisols
507:Histosol
497:Gleysols
482:Durisols
477:Cryosols
447:Andosols
437:Acrisols
315:luvisols
246:Devonian
199:horizons
183:Rainfall
869:Eluvium
829:Bay mud
794:Caliche
784:Hardpan
779:Claypan
769:Subsoil
764:Topsoil
650:Oxisols
552:Podzols
442:Alisols
430:(1998–)
254:Permian
170:England
138:Equator
80:scholar
979:Yedoma
914:Muskeg
144:, the
142:Russia
82:
75:
68:
61:
53:
959:Takir
894:Loess
203:humus
174:Wales
158:China
154:Korea
150:Japan
87:JSTOR
73:books
924:Peat
759:Loam
754:Clay
749:Silt
744:Sand
211:loam
172:and
164:and
134:soil
59:news
909:Mud
42:by
1010::
261:pH
213:.
156:,
152:,
410:e
403:t
396:v
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252:(
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94:(
84:·
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