Soil formation - Knowledge

1120:, tends to undo or counteract the tendency of other soil-forming processes that create distinct horizons. Termites and ants may also retard soil profile development by denuding large areas of soil around their nests, leading to increased loss of soil by erosion. Large animals such as gophers, moles, and prairie dogs bore into the lower soil horizons, bringing materials to the surface. Their tunnels are often open to the surface, encouraging the movement of water and air into the subsurface layers. In localized areas, they enhance mixing of the lower and upper horizons by creating and later refilling the tunnels. Old animal burrows in the lower horizons often become filled with soil material from the overlying A horizon, creating profile features known as 1275:

being in a constant state-of-change under the influence of fluctuating soil-forming factors. That time period depends strongly on climate, parent material, relief, and biotic activity. For example, recently deposited material from a flood exhibits no soil development as there has not been enough time for the material to form a structure that further defines soil. The original soil surface is buried, and the formation process must begin anew for this deposit. Over time the soil will develop a profile that depends on the intensities of biota and climate. While a soil can achieve relative stability of its properties for extended periods, the soil life cycle ultimately ends in soil conditions that leave it vulnerable to erosion. Despite the inevitability of

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generally decrease with depth. Physical disintegration begins as rocks that have solidified deep in the Earth are exposed to lower pressure near the surface and swell and become mechanically unstable. Chemical decomposition is a function of mineral solubility, the rate of which doubles with each 10 °C rise in temperature but is strongly dependent on water to effect chemical changes. Rocks that will decompose in a few years in tropical climates will remain unaltered for millennia in deserts. Structural changes are the result of

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their bodies. They aerate and stir the soil and create stable soil aggregates, after having disrupted links between soil particles during the intestinal transit of ingested soil, thereby assuring ready infiltration of water. As ants and termites build mounds, earthworms transport soil materials from one horizon to another. Other important functions are fulfilled by earthworms in the soil ecosystem, in particular their intense

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affecting the movement of ions and particles through the soil, and aid in the development of different soil profiles. Soil profiles are more distinct in wet and cool climates, where organic materials may accumulate, than in wet and warm climates, where organic materials are rapidly consumed. The effectiveness of water in weathering parent rock material depends on seasonal and daily temperature fluctuations, which favour

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the rock, while temperature gradients within the rock can cause exfoliation of "shells". Cycles of wetting and drying cause soil particles to be abraded to a finer size, as does the physical rubbing of material as it is moved by wind, water, and gravity. Organisms may reduce parent material size and create crevices and pores through the mechanical action of plant roots and the digging activity of animals.

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can be defined by varying a single factor and keeping the other factors constant. This had led to the development of empirical models to describe pedogenesis, such as climofunctions, biofunctions, topofunctions, lithofunctions, and chronofunctions. Since Jenny published his formulation in 1941, it has been used by innumerable

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there is less plant contribution to soil formation. For all of these reasons, steep slopes prevent the formation of soil from getting very far ahead of soil destruction. Therefore, soils on steep terrain tend to have rather shallow, poorly developed profiles in comparison to soils on nearby, more level sites.

713:: the colder or drier the climate the lesser atmospheric carbon is fixed as organic matter while the lesser organic matter is decomposed. Climate also indirectly influences soil formation through the effects of vegetation cover and biological activity, which modify the rates of chemical reactions in the soil. 1149:

affect the type of plants that can grow in a given location. Dead plants and fallen leaves and stems begin their decomposition on the surface. There, organisms feed on them and mix the organic material with the upper soil layers; these added organic compounds become part of the soil formation process.

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Earthworms, ants, termites, moles, gophers, as well as some millipedes and tenebrionid beetles, mix the soil as they burrow, significantly affecting soil formation. Earthworms ingest soil particles and organic residues, enhancing the availability of plant nutrients in the material that passes through

649:, the opposite of oxidation, means the removal of oxygen, hence the oxidation number of some part of the mineral is reduced, which occurs when oxygen is scarce. The reduction of minerals leaves them electrically unstable, more soluble and internally stressed and easily decomposed. It mainly occurs in 6592:

The present paradigm views humus as a system of heteropolycondensates, largely produced by the soil microflora, in varying associations with clay (Anderson 1979). Because this conceptual model, and simulation models rooted within the concept, do not accommodate a large char component, a considerable

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Likewise, a deficiency of water is a major factor in determining the characteristics of soils of dry regions. Soluble salts are not leached from these soils, and in some cases they build up to levels that curtail plant and microbial growth. Soil profiles in arid and semi-arid regions are also apt to

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is the first stage in the transformation of parent material into soil. Temperature fluctuations cause expansion and contraction of the rock, splitting it along lines of weakness. Water may then enter the cracks and freeze and cause the physical splitting of material along a path toward the center of

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There are two principal methods by which the state equation may be solved: first in a theoretical or conceptual manner by logical deductions from certain premises, and second empirically by experimentation or field observation. The empirical method is still mostly employed today, and soil formation

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lichens). The grazing activity of these ecosystem engineers disrupts the limestone, resulting in the weathering and the subsequent formation of soil. They have a significant effect on the region: the population of snails is estimated to process between 0.7 and 1.1 metric ton per hectare per year of

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on Earth, but the vast majority of organisms in soil are microbes, a great many of which have not been described. There may be a population limit of around one billion cells per gram of soil, but estimates of the number of species vary widely from 50,000 per gram to over a million per gram of soil.

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Steep slopes encourage rapid soil loss by erosion and allow less rainfall to enter the soil before running off and hence, little mineral deposition in lower profiles (illuviation). In semiarid regions, the lower effective rainfall on steeper slopes also results in less complete vegetative cover, so

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marks the development of a soil or pedogenesis. With time, soils will evolve features that depend on the interplay of the prior listed soil-forming factors. It takes decades to several thousand years for a soil to develop a profile, although the notion of soil development has been criticized, soil

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is a particular example of a residual soil formed from the transformation of granite, metamorphic and other types of bedrock into clay minerals. Often called weathered granite, saprolite is the result of weathering processes that include: hydrolysis, chelation from organic compounds, hydration and

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The weathering of parent material takes the form of physical weathering (disintegration), chemical weathering (decomposition) and chemical transformation. Weathering is usually confined to the top few meters of geologic material, because physical, chemical, and biological stresses and fluctuations

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can penetrate many metres through the different soil layers to bring up nutrients from deeper in the profile. Plants have fine roots that excrete organic compounds (sugars, organic acids, mucilage), slough off cells (in particular at their tip), and are easily decomposed, adding organic matter to

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interact to determine how effectively precipitation can influence soil formation. The greater the depth of water penetration, the greater the depth of weathering of the soil and its development. Surplus water percolating through the soil profile transports soluble and suspended materials from the

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and depressions where runoff water tends to concentrate, the regolith is usually more deeply weathered, and soil profile development is more advanced. However, in the lowest landscape positions, water may saturate the regolith to such a degree that drainage and aeration are restricted. Here, the

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Topography determines exposure to weather, fire, and other forces of man and nature. Mineral accumulations, plant nutrients, type of vegetation, vegetation growth, erosion, and water drainage are dependent on topographic relief. Soils at the bottom of a hill will get more water than soils on the

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fungi and rhizosphere bacteria, and improve the soil structure. The type and amount of vegetation depend on climate, topography, soil characteristics and biological factors, mediated or not by human activities. Soil factors such as density, depth, chemistry, pH, temperature and moisture greatly

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Soil-forming factors continue to affect soils during their existence, even on stable landscapes that are long-enduring, some for millions of years. Materials are deposited on top or are blown or washed from the surface. With additions, removals and alterations, soils are always subject to new

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Climate directly affects the rate of weathering and leaching. Wind moves sand and smaller particles (dust), especially in arid regions where there is little plant cover, depositing it close to or far from the entrainment source. The type and amount of precipitation influence soil formation by

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Soil formation is influenced by at least five classic factors that are intertwined in the evolution of a soil. They are: parent material, climate, topography (relief), organisms, and time. When reordered to climate, organisms, relief, parent material, and time, they form the acronym CLORPT.

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The idea that climate, vegetation, topography, parent material, and time control soils occurs in the writings of early naturalists. An explicit formulation was performed by Dokuchaev in 1898 in an obscure Russian journal unknown to western writers. He set down: soil = f(cl, o, p)

1097:(according to climate and topography). Tillage mixes the different soil layers, restarting the soil formation process as less weathered material is mixed with the more developed upper layers, resulting in net increased rate of mineral weathering. 676:

and degree of consolidation), and the rate and type of weathering transforms the parent material into a different mineral. The texture, pH and mineral constituents of saprolite are inherited from its parent material. This process is also called

1319:, commonly regarded as the father of pedology, determined in 1883 that soil formation occurs over time under the influence of climate, vegetation, topography, and parent material. He demonstrated this in 1898 using the soil forming equation: 1152:

The influence of humans, and by association, fire, are state factors placed within the organisms state factor. Humans can import or extract nutrients and energy in ways that dramatically change soil formation. Accelerated soil erosion from

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in which they form, with a feedback to climate through transfer of carbon stocked in soil horizons back to the atmosphere. If warm temperatures and abundant water are present in the profile at the same time, the processes of weathering,

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during driest months while they dry it during moister months, thereby acting as a buffer against strong moisture variation. Plants can form new chemicals that can break down minerals, both directly and indirectly through

705:) and temperature, both of which affect the rates of chemical, physical, and biological processes. Temperature and moisture both influence the organic matter content of soil through their effects on the balance between 3937: 967:

are particularly influential in the mineral transformations critical to the soil forming process. Additionally, some bacteria can fix atmospheric nitrogen, and some fungi are efficient at extracting deep soil

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weathering of some minerals and the decomposition of organic matter are retarded, while the loss of iron and manganese is accelerated. In such low-lying topography, special profile features characteristic of

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Roesch, Luiz F.W.; Fulthorpe, Roberta R.; Riva, Alberto; Casella, George; Hadwin, Alison K.M.; Kent, Angela D.; Daroub, Samira H.; Camargo, Flavio A.O.; Farmerie, William G.; Triplett, Eric W. (2007).

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production has abruptly modified soil formation. Likewise, irrigating soil in an arid region drastically influences soil-forming factors, as does adding fertilizer and lime to soils of low fertility.

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Vegetation impacts soils in numerous ways. It can prevent erosion caused by excessive rain that might result from surface runoff. Plants shade soils, keeping them cooler and slowing evaporation of

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Luehmann, Michael D.; Peter, Brad G.; Connallon, y Christopher B.; Schaetz, Randall J.; Smidt, Samuel J.; Liu, Wei; Kincare, Kevin A.; Walkowiak, Toni A.; Thorlund, Elin; Holler, Marie S. (2016).

661:. Chemical weathering becomes more effective as the surface area of the rock increases, thus is favoured by physical disintegration. This stems in latitudinal and altitudinal climate gradients in 5772: 3853:"The mechanics and geological implications of dust transport and deposition in deserts with particular reference to loess formation and dune sand diagenesis in the northern Negev, Israel" 1023:, allowing moisture and gases to move about, a process called bioturbation. In the same way, plant roots penetrate soil horizons and open channels upon decomposition. Plants with deep 6695: 533:

result when minerals are made soluble by water or are changed in structure. The first three of the following list are solubility changes, and the last three are structural changes.

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and base content at the foot of hills and mountains. However, many other factors like drainage and erosion interact with slope position, blurring its expected influence on

3034: 368:. Transported materials are those that have been deposited by water, wind, ice or gravity. Cumulose material is organic matter that has grown and accumulates in place. 2606: 7070: 4248: 1035:

Microorganisms, including fungi and bacteria, effect chemical exchanges between roots and soil and act as a reserve of nutrients in a soil biological hotspot called

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Pimentel, David; Harvey, Celia; Resosudarmo, Pradnja; Sinclair, Kevin; Kurz, D.; McNair, M.; Crist, S.; Shpritz, Lisa; Fitton, L.; Saffouri, R.; Blair, R. (1995).

4146:"The effects of topography on forest soil characteristics in the Oregon Cascade Mountains (USA): implications for the effects of climate change on soil properties" 672:

physical processes that include freezing and thawing. The mineralogical and chemical composition of the primary bedrock material, its physical features (including

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Parent materials are classified according to how they came to be deposited. Residual materials are mineral materials that have weathered in place from primary

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Dere, Ashlee L.; White, Timothy S.; April, Richard H.; Reynolds, Bryan; Miller, Thomas E.; Knapp, Elizabeth P.; McKay, Larry D.; Brantley, Susan L. (2013).

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A System of Quantitative Pedology. New York: Dover Press. (Reprint, with foreword by R. Amundson, of the 1941 McGraw-Hill publication). pdf file format.

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and swell due to the relatively large size of oxygen, leaving it stressed and more easily attacked by water (hydrolysis) or carbonic acid (carbonation).

7252: 4050:"Surface temperature differences between minerals in crystalline rocks: implications for granular disaggregation of granites through thermal fatigue" 3433: 2276: 1954: 6727:

Crews, Timothy E.; Kitayama, Kanehiro; Fownes, James H.; Riley, Ralph H.; Herbert, Darrell A.; Mueller-Dombois, Dieter; Vitousek, Peter M. (1995).

4537:"Glomalin contributed more to carbon, nutrients in deeper soils, and differently associated with climates and soil properties in vertical profiles" 681:, resulting in the formation of sandy soils, thanks to the much higher resistance of quartz compared to other mineral components of granite (e.g., 141:) released by weathering and produce organic acids and specialized proteins which contribute in turn to mineral weathering. They also leave behind 8502: 1082:). Microaggregates (20–250 μm) are ingested by soil mesofauna and fauna, and bacterial bodies are partly or totally digested in their guts. 371:

Residual soils are soils that develop from their underlying parent rocks and have the same general chemistry as those rocks. The soils found on

8538: 6917: 2222: 2168: 8757: 7414: 3326: 3116:"Soil phosphorus fractionation and phosphorus-use efficiencies of tropical rainforests along altitudinal gradients of Mount Kinabalu, Borneo" 1511:

all over the world as a qualitative list for understanding the factors that may be important for producing the soil pattern within a region.

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soils may develop. Depressions allow the accumulation of water, minerals and organic matter, and in the extreme, the resulting soils will be

5750:"Burrows of semi-fossorial vertebrates in upland communities of Central Florida: their architecture, dispersion and ecological consequences" 3933:"Long-range transport of mineral dust in the global atmosphere: impact of African dust on the environment of the southeastern United States" 2365: 5072: 2169:"The fractionation of soil aggregates associated with primary particles influencing wind erosion rates in arid to semiarid environments" 1238:

The effects of ancient ecosystems are not as easily observed, and this challenges the understanding of soil formation. For example, the

1923: 1039:. The growth of roots through the soil stimulates microbial populations, stimulating in turn the activity of their predators (notably 1636:

Samuels, Toby; Bryce, Casey; Landenmark, Hanna; Marie-Loudon, Claire; Nicholson, Natasha; Stevens, Adam H.; Cockell, Charles (2020).

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Of the above, hydrolysis and carbonation are the most effective, in particular in regions of high rainfall, temperature and physical

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compounds producing a solution of ions and water, removing those minerals and reducing the rock's integrity, at a rate depending on

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Bormann, Bernard T.; Spaltenstein, Henri; McClellan, Michael H.; Ugolini, Fiorenzo C.; Cromack, Kermit Jr; Nay, Stephan M. (1995).

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Bohlen, Patrick J.; Scheu, Stefan; Hale, Cindy M.; McLean, Mary Ann; Migge, Sonja; Groffman, Peter M.; Parkinson, Dennis (2004).

5276: 4920: 4376: 3041: 2269:"Loamy, two-storied soils on the outwash plains of southwestern lower Michigan: pedoturbation of loess with the underlying sand" 748:

Water is essential for all the major chemical weathering reactions. To be effective in soil formation, water must penetrate the

8590: 8051: 6024: 4123: 2985:"Erosional and climatic effects on long-term chemical weathering rates in granitic landscapes spanning diverse climate regimes" 2717: 6429: 797:

movement of water, which has dissolved iron and aluminum salts, is responsible for the formation of a superficial hard pan of

6942: 6842: 6823: 4648: 4428: 4102: 3880: 3837: 2672: 2653: 2429: 2153: 2134: 2044: 1661: 1605: 1571: 1174: 7209: 1744:"The role of pedogenic overprinting in the obliteration of parent material in some polygenetic landscapes of Sicily (Italy)" 8528: 7349:

Stanley W. Buol, F.D. Hole and R.W. McCracken. 1997. Soil Genesis and Classification, 4th ed. Iowa State Univ. Press, Ames

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of North America. In more recent times, human destruction of natural vegetation and subsequent tillage of the soil for

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Burke, Ingrid C.; Yonker, Caroline M.; Parton, William J.; Cole, C. Vernon; Flach, Klaus; Schimel, David S. (1989).

8583: 8523: 8507: 7170: 6567: 6020:"Root-associated bacteria contribute to mineral weathering and to mineral nutrition in trees: a budgeting analysis" 5857: 4601: 2984: 2067: 1781: 4419: 4185: 2937:

Favre, Fabienne; Tessier, Daniel; Abdelmoula, Mustapha; Génin, Jean-Marie; Gates, Will P.; Boivin, Pascal (2002).

2546:"Soil CO2 dynamics, acidification, and chemical weathering in a temperate forest with experimental CO2 enrichment" 8793: 8561: 6169: 4872: 3618: 3072: 2844: 2748: 2692: 2502: 437: 8045: 9002: 8803: 8566: 8550: 8056: 7439: 7215: 6350: 5809: 2063: 1491:

Jenny's state equation in Factors of Soil Formation differs from the Vasily Dokuchaev equation, treating time (

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Distinct ecosystems produce distinct soils, sometimes in easily observable ways. For example, three species of

30:"Pedogenesis" redirects here. For the reproduction by an organism that has not achieved physical maturity, see 386:

Most soils derive from transported materials that have been moved many miles by wind, water, ice and gravity:

7577: 5448: 5272:"A comparison of mineral weathering trends between two management systems on a catena of loess-derived soils" 4150: 3494: 3486: 2095: 1290:, in which soils of different ages but with minor differences in other soil-forming factors can be compared. 1258:

Time is a factor in the interactions of all the above. While a mixture of sand, silt and clay constitute the

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conditions. Whether these are slow or rapid changes depends on climate, topography and biological activity.

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Very intense chemical weathering, leaching, and erosion in warm and humid regions where soil does not freeze

8743: 7400: 5165:"A history of research on the link between (micro)aggregates, soil biota, and soil organic matter dynamics" 4432: 4284:"Relations of soil properties to topography and vegetation in a subtropical rain forest in southern Taiwan" 3750: 1698: 7364: 2268: 1135:, plants can cause soils to lose moisture, resulting in complex and highly variable relationships between 8518: 8076: 6971: 4455:"Effect of soil and topographic properties on crop yield in a North-Central corn–soybean cropping system" 621:

is the inclusion of water in a mineral structure, causing it to swell and leaving it stressed and easily

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in the case of stationary glaciers. Retreating glaciers leave smoother ground moraines, and in all cases

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Francis D. Hole and J.B. Campbell. 1985. Soil landscape analysis. Totowa Rowman & Allanheld, 214 p.

5203:"Alimentary studies on the collembolan Paratullbergia callipygos using transmission electron microscopy" 4623: 777:

waters. Thus, percolating water stimulates weathering reactions and helps differentiate soil horizons.

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Climate is the dominant factor in soil formation, and soils show the distinctive characteristics of the

8697: 8533: 8061: 7500: 6514: 5624:"Soil invertebrates as ecosystem engineers: intended and accidental effects on soil and feedback loops" 4968: 4493:

Thelemann, Ryan; Johnson, Gregg; Sheaffer, Craig; Banerjee, Sudipto; Cai, Haowen; Wyse, Donald (2010).

3798: 3568:"Fluxes and concentrations of dissolved organic carbon and nitrogen: a synthesis for temperate forests" 734: 733:, humid climates favor the growth of trees. In contrast, grasses are the dominant native vegetation in 650: 6332:"Evolution and origin of the Central Grassland of North America: climate, fire, and mammalian grazers" 5774:

Transactions of the 9th International Congress of Soil Science, Adelaide, Australia, August 5–15, 1968

3322:"The role of plants in controlling rates and products of weathering: importance of biological pumping" 939:, and exposure to the elements. Gravity transports water downslope, together with mineral and organic 8808: 7505: 6205:

Brêthes, Alain; Brun, Jean-Jacques; Jabiol, Bernard; Ponge, Jean-François; Toutain, François (1995).

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Highways through the soil: properties of preferential flow paths and transport of reactive compounds

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Each soil has a unique combination of microbial, plant, animal and human influences acting upon it.

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Cumulose parent material is not moved but originates from deposited organic material. This includes

8655: 8449: 8071: 2887: 770: 406: 165: 6382:"Texture, climate, and cultivation effects on soil organic matter content in U.S. grassland soils" 6123:

Dai, Shengpei; Zhang, Bo; Wang, Haijun; Wang, Yamin; Guo, Lingxia; Wang, Xingmei; Li, Dan (2011).

3220: 3180:"Weathering of granites in a temperate climate (NW Portugal): granitic saprolites and arenization" 2496:

Landeweert, Renske; Hoffland, Ellis; Finlay, Roger D.; Kuyper, Thom W.; Van Breemen, Nico (2001).

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Scalenghe, Riccardo; Territo, Claudio; Petit, Sabine; Terribile, Fabio; Righi, Dominique (2016).

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The number of organisms and species can vary widely according to soil type, location, and depth.

234: 1868:"Exploring pedogenesis via nuclide-based soil production rates and OSL-based bioturbation rates" 1783:

Soil development and ecological succession in a deglaciated area of Muir Inlet, Southeast Alaska

1531:, where change in an ancient river course led to millennia of salinity buildup and formation of 101:. The study of pedogenesis is important to understanding soil distribution patterns in current ( 8343: 7717: 6980: 3566:

Michalzik, Beate; Kalbitz, Karsten; Park, Ji-Hyung; Solinger, Stephan; Matzner, Egbert (2001).

2744:"Experimental study of anorthite dissolution and the relative mechanism of feldspar hydrolysis" 2451: 1117: 722: 622: 383:

are residual soils. In the United States as little as three percent of the soils are residual.

193: 7335: 6729:"Changes in soil phosphorus and ecosystem dynamics along a long term chronosequence in Hawaii" 6479:"Impact of N fertilization on subsoil properties: soil organic matter and aggregate stability" 4098:"Physical deterioration of sedimentary rocks subjected to experimental freeze–thaw weathering" 168:

rate due to weathering is approximately 1/10 mm per year. New soils can also deepen from

8714: 8398: 4743:"Computational improvements reveal great bacterial diversity and high metal toxicity in soil" 4349: 1790: 1056: 988:

supports microbial activity. Animals serve to decompose plant materials and mix soil through

177: 6407: 5297: 4397: 3005: 93:, the study of soil in its natural environment. Other branches of pedology are the study of 8920: 8877: 8788: 8479: 8373: 8197: 7111: 7038: 6395: 6251: 6033: 5937: 5781: 5285: 4929: 4756: 4550: 4385: 4111: 4063: 4007: 3946: 3860: 3759: 3383: 3335: 3129: 3081: 3001: 2939:"Iron reduction and changes in cation exchange capacity in intermittently waterlogged soil" 2896: 2853: 2757: 2701: 2557: 2445:

Uroz, Stéphane; Calvaruso, Christophe; Turpault, Marie-Pierre; Frey-Klett, Pascale (2009).

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from the Global Change 1 Lectures. University of Michigan. Url last accessed on 2007-03-31

6430:"Assessment and forecast of soil formation under irrigation in the steppe zone of Ukraine" 5240: 4535:

Wang, Wenjie; Zhong, Zhaoliang; Wang, Qiong; Wang, Humei; Fu, Yujie; He, Xingyuan (2017).

4372:"Soil-geomorphic relations on the Blue Ridge Front. I. Regolith types and slope processes" 4282:

Chen, Zueng-Sang; Hsieh, Chang-Fu; Jiang, Feei-Yu; Hsieh, Tsung-Hsin; Sun, I-Fang (1997).

3274:"Regional patterns of decomposition and primary production rates in the U.S. Great Plains" 1139:(measuring light interception) and moisture loss: more generally plants prevent soil from 852:

cycles are an effective mechanism which breaks up rocks and other consolidated materials.

8: 7766: 7707: 7668: 6862: 4683: 4632: 3487:"Rock to regolith conversion: producing hospitable substrates for terrestrial ecosystems" 1190: 1093:, fire and leaving soils bare. This can lead to erosion, waterlogging, lateritization or 610: 585: 98: 7331: 7115: 7042: 6478: 6399: 6294:"Charcoal consumption and casting activity by Pontoscolex corethurus (Glossoscolecidae)" 6255: 6037: 5941: 5771:

Borst, George (1968). "The occurrence of crotovinas in some southern California soils".

5289: 4933: 4760: 4554: 4389: 4115: 4067: 4011: 3950: 3864: 3763: 3631: 3387: 3339: 3133: 3085: 2900: 2857: 2792:"Carbonic acid: an important intermediate in the surface chemistry of calcium carbonate" 2761: 2705: 2561: 2238: 2223:"Rates and processes of soil evolution on uplifted marine terraces, northern California" 2184: 1829: 444:

of California are the beds of ancient seas that have been revealed as the land uplifted.

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Jouquet, Pascal; Dauber, Jens; Lagerlöf, Jan; Lavelle, Patrick; Lepage, Michel (2006).

5597: 5549: 5503: 5417: 5046: 4836: 4780: 4716: 4654: 4571: 4541: 4536: 4305: 4216: 4023: 3905: 3886: 3711: 3587: 3455: 3409: 3295: 3243: 3153: 3068:"Climate dependence of feldspar weathering in shale soils along a latitudinal gradient" 2958: 2912: 2623: 2575: 2339: 2293: 2196: 1971: 1841: 1717: 1667: 1110: 873: 706: 702: 617: 492: 258: 6858:"Fifteen years of vegetation and soil development after brackish-water marsh creation" 6797: 6165:"Environmental factors and vegetation composition, Lefka Ori Massif, Crete, S. Aegean" 5949: 5461: 5218: 4990: 3992:

Post, Wilfred M.; Emanuel, William R.; Zinke, Paul J.; Stangerberger, Alan G. (1999).

3545: 3370:"Temperature sensitivity of soil carbon decomposition and feedbacks to climate change" 3198: 2515: 1242:

of the North American tallgrass prairie have a humus fraction nearly half of which is

172:. Gradually soil is able to support higher forms of plants and animals, starting with 8997: 8948: 8925: 8857: 8363: 8232: 7623: 7470: 7369: 7350: 7295: 7265: 7219: 7174: 7123: 7054: 7029: 7002: 6966: 6938: 6875: 6733: 6728: 6526: 6381: 6263: 6183: 6124: 6078: 6059: 5709: 5661: 5529: 5359: 5164: 5145: 5140: 5121: 4995: 4915: 4889: 4841: 4784: 4772: 4747: 4708: 4644: 4576: 4494: 4283: 4242: 3974: 3969: 3932: 3890: 3876: 3852: 3793: 3707: 3691: 3567: 3460: 3401: 3321: 3278: 3273: 3145: 2954: 2916: 2908: 2882: 2813: 2769: 2687: 2627: 2579: 2545: 2519: 2468: 2425: 2343: 2297: 2246: 2200: 2012: 2008: 1967: 1845: 1813: 1721: 1693: 1671: 1657: 1637: 1601: 1567: 884:. The topographical setting may either hasten or retard the work of climatic forces. 789:

horizons). In tropical soils, when the soil has been deprived of vegetation (e.g. by

757: 738: 726: 565: 512: 390: 169: 8735: 7273: 7066: 6914:"Chapter 10: Quantifying the effects of earthworms on soil aggregation and porosity" 6913: 6883: 6643: 6562: 6456: 6359: 6293: 6271: 6102: 6045: 5997: 5830: 5601: 5553: 5507: 5421: 5050: 4720: 4658: 3715: 3591: 3247: 3157: 2962: 2838:

Jiménez-González, Inmaculada; Rodríguez-Navarro, Carlos; Scherer, George W. (2008).

2619: 2058: 1975: 1556:

Buol, Stanley W.; Southard, Randal J.; Graham, Robert C.; McDaniel, Paul A. (2011).

478:

and results from preservation of plant residues by the low oxygen content of a high

8813: 8544: 8237: 7700: 7261: 7119: 7046: 6994: 6990: 6930: 6871: 6793: 6742: 6679: 6666:"Soil development in relation to vegetation and surface age at Glacier Bay, Alaska" 6623: 6576: 6518: 6444: 6403: 6345: 6305: 6259: 6218: 6178: 6136: 6090: 6049: 6041: 5985: 5945: 5926:"The influence of vegetation on the summertime evolution of European soil moisture" 5899: 5866: 5818: 5723: 5675: 5635: 5589: 5541: 5495: 5457: 5409: 5398:"Earthworm effects on selected physical and chemical properties of soil aggregates" 5371: 5333: 5293: 5214: 5176: 5135: 5095: 5087: 5038: 4985: 4977: 4937: 4881: 4831: 4823: 4814: 4764: 4742: 4700: 4691: 4636: 4566: 4558: 4508: 4499: 4468: 4459: 4393: 4345: 4336: 4309: 4297: 4257: 4208: 4200: 4159: 4119: 4075: 4071: 4027: 4015: 3998: 3964: 3954: 3868: 3807: 3767: 3703: 3665: 3627: 3579: 3541: 3503: 3450: 3442: 3428: 3413: 3391: 3374: 3347: 3343: 3287: 3235: 3194: 3137: 3089: 3009: 2950: 2904: 2861: 2805: 2765: 2709: 2615: 2565: 2511: 2460: 2331: 2285: 2242: 2192: 2188: 2167:

Shahabinejad, Nader; Mahmoodabadi, Majid; Jalalian, Ahmad; Chavoshi, Elham (2019).

2104: 1963: 1879: 1833: 1755: 1707: 1649: 1524: 1316: 900: 806: 794: 638: 230: 226: 7145: 7050: 5853:"Distinction of soil thermal regimes under various experimental vegetation covers" 5662:"Non-native invasive earthworms as agents of change in northern temperate forests" 3872: 2392: 2289: 1250:

capable of producing these distinct deep rich black soils is not easily observed.

1116:

In general, the mixing of the soil by the activities of animals, sometimes called

1105:

production, both within the intestine and as a lining in their galleries, exert a

8910: 8900: 8665: 8645: 8640: 8469: 8403: 8388: 8368: 8302: 8287: 8147: 7643: 7572: 7540: 6309: 6141: 5888:"How does a shelter of solar panels influence water flows in a soil-crop system?" 5639: 5126: 4163: 3669: 2688:"Scale dependence of mineral dissolution rates within single pores and fractures" 2498:"Linking plants to rocks: ectomycorrhizal fungi mobilize nutrients from minerals" 2108: 1759: 1645: 1563: 1528: 1500: 1136: 1072: 845: 545: 447:

Ice moves parent material and makes deposits in the form of terminal and lateral

441: 429: 218: 189: 173: 142: 122: 94: 79: 51: 5805:"Impact of plant roots on the resistance of soils to erosion by water: a review" 5180: 4916:"Crop cover root channels may alleviate soil compaction effects on soybean crop" 3811: 805:, respectively, which is improper for cultivation, a known case of irreversible 424:, or marine. Alluvial materials are those moved and deposited by flowing water. 8977: 8905: 8847: 8842: 8674: 8597: 8277: 8222: 7685: 7658: 7638: 7495: 7490: 6780:"Soil chronosequences, soil development, and soil evolution: a critical review" 6563:"Importance of charred organic matter in Black Chernozem soils of Saskatchewan" 5976: 5580: 5099: 4885: 4562: 3938:

Proceedings of the National Academy of Sciences of the United States of America

3013: 1385:

published in 1941 a state equation for the factors influencing soil formation:

1287: 1106: 1063:

colonies to which clay particles are glued, offering them a protection against

1048: 1012: 1004: 924: 877: 841: 837: 742: 598: 154: 67: 6665: 6506: 6448: 6240:"The place of humans in the state factor theory of ecosystems and their soils" 6223: 6206: 6094: 5989: 5903: 5822: 4640: 4301: 3583: 3179: 3093: 2713: 2464: 2089:

Rahardjo, Harianto; Aung, K. K.; Leong, Eng Choon; Rezaur, R. Bhuiyan (2004).

1837: 1653: 980:. Plants hold soil against erosion, and accumulated plant material build soil 200:

as organic matter accumulates and mineral weathering and leaching take place.

8991: 8892: 8852: 8708: 8611: 8604: 8444: 8413: 8322: 8207: 7712: 7589: 7545: 7247: 6857: 6784: 6163:

Vogiatzakis, Ioannis; Griffiths, Geoffrey H.; Mannion, Antoinette M. (2003).

5091: 3654:"Microbial biomass and activity in salt affected soils under arid conditions" 2417: 1158: 1132: 1128: 1094: 985: 964: 928: 923:. These patterns emerge from topographic differences in erosion, deposition, 920: 790: 710: 698: 602: 504: 452: 181: 106: 59: 5930:

Physics and Chemistry of the Earth, Part B, Hydrology, Oceans and Atmosphere

5749: 5375: 4768: 4513: 4472: 1712: 1302: 58:) within soils. These alterations lead to the development of layers, termed 8958: 8882: 8775: 8464: 8459: 8434: 8307: 8252: 7680: 7653: 7628: 7584: 7557: 7485: 7480: 7475: 7465: 7423: 7058: 7025:"Environmental and economic cost of soil erosion and conservation benefits" 6239: 6164: 6063: 5971: 5925: 5887: 5804: 5271: 5149: 5042: 4999: 4963: 4941: 4893: 4845: 4809: 4776: 4712: 4580: 4454: 4371: 4331: 4145: 3993: 3978: 3959: 3771: 3653: 3613: 3529: 3464: 3446: 3405: 3269: 3149: 2840:"Role of clay minerals in the physicomechanical deterioration of sandstone" 2817: 2791: 2743: 2601: 2523: 2472: 2446: 2367:

Peat muck and mud deposits: their nature, composition and agricultural uses

2002: 1867: 1743: 1640:. In Dontsova, Katerina; Balogh-Brunstad, Zsuzsanna; Le Roux, Gaël (eds.). 1557: 1259: 1247: 1219: 1198: 1161: 989: 948: 936: 932: 909: 881: 717: 458:

Parent material moved by gravity is obvious at the base of steep slopes as

410: 222: 197: 71: 31: 8823: 6934: 6522: 6018:

Calvaruso, Christophe; Turpault, Marie-Pierre; Frey-Klett, Pascal (2006).

5499: 4827: 3652:

Yuan, Bing-Cheng; Li, Zi-Zhen; Liu, Hua; Gao, Meng; Zhang, Yan-Yu (2007).

3239: 3141: 2938: 1979: 1595: 697:

The principal climatic variables influencing soil formation are effective

86:

distribution, forming in response to differences in soil forming factors.

8660: 8474: 8408: 8378: 8312: 8292: 8212: 8192: 8172: 8162: 8157: 7690: 7613: 7594: 7164: 5444:"Earthworms, water infiltration and soil stability: some new assessments" 5443: 5319: 4097: 3067: 2866: 2839: 2570: 2319: 1919: 1508: 1166: 1154: 1140: 1064: 1036: 973: 849: 766: 593: 568:

molecules by the splitting of intervening water. This results in soluble

479: 475: 433: 250: 196:

of organic matter with weathered minerals. As soils mature, they develop

102: 6607:"Rapid soil development after windthrow disturbance in pristine forests" 5575: 5397: 4595: 4261: 4212: 3692:"Carbon storage in the caliche of arid soils: a case study from Arizona" 3396: 3369: 3115: 2837: 2373:. Ottawa, Ontario, Canada: Dominion of Canada, Department of Agriculture 2166: 2091:"Characteristics of residual soils in Singapore as formed by weathering" 1694:"When plants eat rocks: functional adaptation of roots on rock outcrops" 50:

genesis as regulated by the effects of place, environment, and history.

8915: 8872: 8862: 8650: 8393: 8297: 8247: 8202: 8187: 8152: 8122: 7988: 7895: 7860: 7835: 7675: 7648: 7633: 7535: 7460: 6754: 6691: 6635: 6593:

change in conceptual understanding (a paradigm shift) appears imminent.

5871: 5852: 5687: 5593: 5545: 5413: 5163:

Six, Johan; Bossuyt, Heleen; De Gryze, Steven; Denef, Karolien (2004).

4981: 4220: 3299: 3178:

Sequeira Braga, Maria Amália; Paquet, Hélène; Begonha, Arlindo (2002).

2660: 2641: 2335: 2320:"Formation, morphology and classification of colluvial soils: a review" 2221:

Merritts, Dorothy J.; Chadwick, Oliver A.; Hendricks, David M. (1991).

2032: 1231: 1214: 1209: 1145: 1068: 1008: 1003:

Plants, animals, fungi, bacteria and humans affect soil formation (see

969: 952: 762: 753: 673: 573: 560: 553: 549: 254: 188:

deepen with the accumulation of humus originating from dead remains of

160:

New soils increase in depth by a combination of weathering and further

150: 118: 63: 55: 8972: 7735: 6125:"Vegetation cover change and the driving factors over northwest China" 5727: 5576:"How do earthworms affect microfloral and faunal community diversity?" 5337: 4124:

10.1002/1096-9837(200011)25:12<1295::AID-ESP138>3.0.CO;2-E

3507: 2809: 8834: 8679: 8454: 8439: 8383: 8282: 8227: 8167: 7930: 7925: 7915: 7850: 7820: 7800: 7729: 7618: 6926: 6830: 4332:"Soil available water as influenced by landscape position and aspect" 4144:

Griffiths, Robert P.; Madritch, Michael D.; Swanson, Alan K. (2009).

4019: 3746:"Improvement of calcareous expansive soils in semi-arid environments" 3120: 1520: 1271: 1239: 1227: 1079: 1052: 996: 869: 686: 668: 629: 569: 508: 482:. While peat may form sterile soils, muck soils may be very fertile. 463: 138: 83: 75: 6965:

He, Changling; Breuning-Madsen, Henrik; Awadzi, Theodore W. (2007).

6746: 6683: 6627: 6580: 5679: 5623: 5483: 5202: 5071:

Widmer, Franco; Pesaro, Manuel; Zeyer, Josef; Blaser, Peter (2000).

4867: 4704: 4330:

Hanna, Abdulaziz Yalda; Harlan, Phillip W.; Lewis, David T. (1982).

4204: 4049: 3825: 3291: 2497: 2141: 2122: 2090: 1883: 1638:"Microbial weathering of minerals and rocks in natural environments" 1047:, and in last turn root growth, a positive feedback called the soil 455:

are left as alluvial deposits are moved downstream from the glacier.

436:

are examples. Marine deposits, such as soils along the Atlantic and

233:, is the source of all soil mineral materials and the origin of all 8635: 8484: 8267: 8182: 8137: 8013: 7993: 7983: 7968: 7940: 7935: 7920: 7890: 7885: 7865: 7855: 7840: 7825: 7815: 7810: 7805: 7695: 7455: 7024: 6967:"Mineralogy of dust deposited during the Harmattan season in Ghana" 6779: 6604: 6505:

Odling-Smee, F. John; Laland, Kevin N.; Feldman, Marcus W. (2003).

6331: 5803:

Gyssels, Gwendolyn; Poesen, Jean; Bochet, Esther; Li, Yong (2005).

4866:

Meysman, Filip J.R.; Middelburg, Jack J.; Heip, Carlo H.R. (2006).

3434:

Philosophical Transactions of the Royal Society of London, Series B

3114:

Kitayama, Kanehiro; Majalap-Lee, Noreen; Aiba, Shin-ichiro (2000).

1948:

Johnson, Donald Lee; Domier, Jane E. J.; Johnson, Diana N. (2005).

1536: 1532: 1485: 1291: 1286:

Time as a soil-forming factor may be investigated by studying soil

1243: 1186: 1075: 1060: 1020: 977: 913: 893: 798: 782: 774: 749: 662: 581: 577: 425: 417: 294: 242: 238: 126: 90: 7246:

Johnson, Donald L.; Domier, Jane E. J.; Johnson, Diana N. (2005).

6079:"Plant-induced changes in soil structure: processes and feedbacks" 5360:"Effects of earthworms on plant growth: patterns and perspectives" 4810:"Pyrosequencing enumerates and contrasts soil microbial diversity" 2983:

Riebe, Clifford S.; Kirchner, James W.; Finkel, Robert C. (2004).

1642:

Biogeochemical cycles: ecological drivers and environmental impact

1635: 1246:. This outcome was not anticipated because the antecedent prairie 1085:

Humans impact soil formation by removing vegetation cover through

8953: 8943: 8766: 8429: 8217: 8177: 8142: 8132: 8127: 8117: 8112: 8008: 7978: 7973: 7963: 7958: 7910: 7905: 7880: 7875: 7870: 7845: 7830: 7795: 7790: 7785: 7601: 7022: 5484:"Earthworm feeding activity and development of the humus profile" 5122:"Protozoa and plant growth: the microbial loop in soil revisited" 5022:"Rhizodeposition of organic C by plants: mechanisms and controls" 4370:

Graham, Robert C.; Daniels, Raymond B.; Buol, Stanley W. (1990).

2883:"Effect of oxygen penetration in silicon due to nano-indentation" 2602:"Influence of climatically induced cycles in physical weathering" 1182: 1178: 1090: 1086: 1024: 944: 905: 861: 817: 802: 786: 658: 606: 448: 376: 365: 352: 285: 185: 130: 117:

Soil develops through a series of changes. The starting point is

4492: 4186:"Factors influencing infiltrability of semiarid mountain slopes" 2447:"Mineral weathering by bacteria: ecology, actors and mechanisms" 1814:"Soil development on the Crimean Peninsula in the Late Holocene" 8327: 8262: 8003: 7998: 7900: 7515: 7392: 6856:

Craft, Christopher; Broome, Stephen; Campbell, Carlton (2002).

2444: 1499:), and pointedly leaving the ellipsis "open" for more factors ( 1223: 1194: 1040: 1016: 752:. The seasonal rainfall distribution, evaporative losses, site 730: 634: 356:

Soil, on an agricultural field in Germany, which has formed on

276: 246: 134: 5710:"The role of termites and ants in soil modification: a review" 3485:

Graham, Robert C.; Rossi, Ann M.; Hubbert, Kenneth R. (2010).

2495: 1741: 793:) and thereby is submitted to intense evaporation, the upward 729:

will be maximized. According to the climatic determination of

8242: 5248: 4184:

Wilcox, Bradford P.; Wood, M. Karl; Tromble, John M. (1988).

4048:

Gómez-Heras, Miguel; Smith, Bernard J.; Fort, Rafael (2006).

3991: 2266: 1102: 981: 865: 741:

regions, while shrubs and brush of various kinds dominate in

645: 500: 496: 459: 413:. Clay is seldom moved by wind as it forms stable aggregates. 402: 380: 357: 146: 7211:

Factors of soil formation: a system of quantitative pedology

5621: 5530:"Mucus excretion and carbon turnover of endogeic earthworms" 3565: 3427:

Woodward, F. Ian; Lomas, Mark R.; Kelly, Colleen K. (2004).

1912:

Factors of soil formation: a system of qunatitative pedology

1597:

Factors of soil formation: a system of quantitative pedology

919:

Recurring patterns of topography result in toposequences or

781:

accumulate carbonates and certain types of expansive clays (

8272: 8107: 8102: 8097: 8092: 7530: 6162: 6017: 3177: 2936: 1456:

organisms (soil microbiology, soil mesofauna, soil biology)

1202: 682: 511:

compounds by bacteria and fungi, thought to increase under

503:. Chemical weathering mainly results from the excretion of 471: 421: 398: 394: 372: 307: 47: 6811: 6351:

10.3159/1095-5674(2006)133[626:EAOOTC]2.0.CO;2

5073:"Preferential flow paths: biological 'hot spots' in soils" 4807: 1692:

Augusto, Laurent; Fanin, Nicolas; Bakker, Mark R. (2019).

1555: 1294:

are soils formed during previous soil forming conditions.

773:. It may also carry away soluble materials in the surface 8257: 7296:"Makgadikgadi: ancient Village or settlement in Botswana" 6841: