Editing Soil formation (section)

===Organisms===
Each soil has a unique combination of microbial, plant, animal and human influences acting upon it. [[Microorganism|Microorganisms]] 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 [[phosphorus]] and increasing [[soil carbon]] levels in the form of [[glomalin]].<ref>{{cite journal |last1=Wang |first1=Wenjie |last2=Zhong |first2=Zhaoliang |last3=Wang |first3=Qiong |last4=Wang |first4=Humei |last5=Fu |first5=Yujie |last6=He |first6=Xingyuan |year=2017 |title=Glomalin contributed more to carbon, nutrients in deeper soils, and differently associated with climates and soil properties in vertical profiles |journal=[[Scientific Reports]] |volume=7 |issue=13003 |page=13003 |doi=10.1038/s41598-017-12731-7 |pmid=29021579 |pmc=5636888 |bibcode=2017NatSR...713003W }}</ref> Plants hold soil against erosion, and accumulated plant material build soil [[humus]] levels. Plant [[Root mucilage|root exudation]] supports microbial activity. Animals serve to decompose plant materials and mix soil through [[bioturbation]].<ref>{{cite book |last1=Van Breemen |first1=Nico |last2=Buurman |first2=Peter |title=Soil formation |year=2003 |edition=Second |publisher=[[Springer Science+Business Media|Kluwer Academic Publishers]] |location=Dordrecht, The Netherlands |url=https://fr1lib.org/book/857347/e9d4a6 |access-date=16 January 2022 }}{{Dead link|date=April 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Soil is the most speciose (species-rich) [[ecosystem]] on Earth, but the vast majority of organisms in soil are microbes, a great many of which have not been described.<ref name="Wall2001">{{cite book |last1=Wall |first1=Diana H. |last2=Adams |first2=Gina |last3=Parsons |first3=Andrew N. |title=Soil biodiversity |series=Ecological Studies |year=2001 |volume=152 |publisher=[[Springer Publishing|Springer]] |location=New York, NY |doi=10.1007/978-1-4613-0157-8 |isbn=978-0-387-95286-4 |s2cid=45261145 |url=https://link.springer.com/content/pdf/10.1007%2F978-1-4613-0157-8.pdf |access-date=16 January 2022 }}</ref><ref name="nature2008">{{cite journal |last=Dance |first=Amber |journal=[[Nature (journal)|Nature]] |title=What lies beneath |year=2008 |volume=455 |issue=7214 |pages=724–25 |pmid=18843336 |doi=10.1038/455724a |s2cid=30863755 |url=http://www.nature.com/news/2008/081008/pdf/455724a.pdf |access-date=16 January 2022 }}</ref> 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.<ref name="Gans2005">{{cite journal |last1=Gans |first1=Jason |last2=Wolinsky |first2=Murray |last3=Dunbar |first3=John |year=2005 |title=Computational improvements reveal great bacterial diversity and high metal toxicity in soil |journal=[[Science (journal)|Science]] |volume=309 |issue=5739 |pages=1387–90 |url=https://www.researchgate.net/publication/7637990 |doi=10.1126/science.1112665 |pmid=16123304 |access-date=16 January 2022 |bibcode=2005Sci...309.1387G |s2cid=130269020 }}</ref><ref name="roesch">{{cite journal |last1=Roesch |first1=Luiz F.W. |last2=Fulthorpe |first2=Roberta R. |last3=Riva |first3=Alberto |last4=Casella |first4=George |last5=Hadwin |first5=Alison K.M. |last6=Kent |first6=Angela D. |last7=Daroub |first7=Samira H. |last8=Camargo |first8=Flavio A.O. |last9=Farmerie |first9=William G. |last10=Triplett |first10=Eric W. |journal=[[The ISME Journal]] |title=Pyrosequencing enumerates and contrasts soil microbial diversity |year=2007 |volume=1 |issue=4 |pages=283–90 |pmc=2970868 |pmid=18043639 |doi=10.1038/ismej.2007.53 |bibcode=2007ISMEJ...1..283R |url=https://art1lib.org/book/10595442/a9ae88 |access-date=16 January 2022 }}</ref> The number of organisms and species can vary widely according to soil type, location, and depth.<ref name="nature2008"/><ref name="roesch"/>

Plants, animals, fungi, bacteria and humans affect soil formation (see [[Soil Biomantle|soil biomantle]] and [[stonelayer]]). Soil animals, including fauna and [[soil mesofauna]], mix soils as they form [[burrow]]s and [[Porosity|pores]], allowing moisture and gases to move about, a process called bioturbation.<ref>{{cite journal |last1=Meysman |first1=Filip J.R. |last2=Middelburg |first2=Jack J. |last3=Heip |first3=Carlo H.R. |year=2006 |title=Bioturbation: a fresh look at Darwin's last idea |journal=[[Trends in Ecology and Evolution]] |volume=21 |issue=12 |pages=688–95 |url=https://www.academia.edu/13631880 |doi=10.1016/j.tree.2006.08.002 |pmid=16901581 |bibcode=2006TEcoE..21..688M |access-date=23 January 2022 }}</ref> In the same way, plant roots penetrate soil horizons and open channels upon decomposition.<ref>{{cite journal |last1=Williams |first1=Stacey M. |last2=Weil |first2=Ray R. |year=2004 |title=Crop cover root channels may alleviate soil compaction effects on soybean crop |journal=[[Soil Science Society of America Journal]] |volume=68 |issue=4 |pages=1403–09 |url=https://www.researchgate.net/publication/240789602 |doi=10.2136/sssaj2004.1403 |access-date=23 January 2022 |bibcode=2004SSASJ..68.1403W }}</ref> Plants with deep [[taproot]]s can penetrate many metres through the different soil layers to bring up nutrients from deeper in the profile.<ref>{{cite journal |last=Lynch |first=Jonathan |year=1995 |title=Root architecture and plant productivity |journal=[[Plant Physiology (journal)|Plant Physiology]] |url=https://art1lib.org/book/64045845/0c6b21 |volume=109 |issue=1 |pages=7–13 |doi=10.1104/pp.109.1.7 |pmid=12228579 |pmc=157559 |access-date=23 January 2022 }}</ref> 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 soil, a process called ''rhizodeposition''.<ref>{{cite journal |last=Nguyen |first=Christophe |year=2003 |title=Rhizodeposition of organic C by plants: mechanisms and controls |journal=[[Agronomy for Sustainable Development|Agronomie]] |volume=23 |issue=5/6 |pages=375–96 |url=https://hal.archives-ouvertes.fr/file/index/docid/886190/filename/hal-00886190.pdf |doi=10.1051/agro:2003011 |bibcode=2003AgSD...23..375N |s2cid=55101606 |access-date=23 January 2022 }}</ref> 

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 [[rhizosphere]].<ref>{{cite thesis |last1=Widmer |first1=Franco |last2=Pesaro |first2=Manuel |last3=Zeyer |first3=Josef |last4=Blaser |first4=Peter |year=2000 |chapter=Preferential flow paths: biological 'hot spots' in soils |doi=10.3929/ethz-a-004036424 |title=Highways through the soil: properties of preferential flow paths and transport of reactive compounds |editor-first=Maya |editor-last=Bundt |publisher=[[ETH]] Library |location=Zurich |pages=53–75 |chapter-url=https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/144808/eth-23683-02.pdf#page=65 |access-date=23 January 2022 |hdl=20.500.11850/144808 }}</ref> The growth of roots through the soil stimulates microbial populations, stimulating in turn the activity of their predators (notably [[amoeba]]), thereby increasing the [[mineralization (soil science)|mineralization rate]], and in last turn root growth, a positive feedback called the soil [[microbial loop]].<ref>{{cite journal |last=Bonkowski |first=Michael |year=2004 |title=Protozoa and plant growth: the microbial loop in soil revisited |journal=[[New Phytologist]] |volume=162 |issue=3 |pages=617–31 |doi=10.1111/j.1469-8137.2004.01066.x |pmid=33873756 |doi-access=free |bibcode=2004NewPh.162..617B }}</ref> Out of root influence, in the [[bulk soil]] most bacteria are in a quiescent stage, forming micro-[[aggregate (composite)|aggregates]], i.e. [[mucilage|mucilaginous]] colonies to which clay particles are glued, offering them a protection against [[desiccation]] and predation by soil [[microfauna]] ([[bacteriophagous]] [[protozoa]] and [[nematodes]]).<ref>{{cite journal |last1=Six |first1=Johan |last2=Bossuyt |first2=Heleen |last3=De Gryze |first3=Steven |last4=Denef |first4=Karolien |year=2004 |title=A history of research on the link between (micro)aggregates, soil biota, and soil organic matter dynamics |journal=Soil and Tillage Research |volume=79 |issue=1 |pages=7–31 |url=https://www.researchgate.net/publication/222426695 |doi=10.1016/j.still.2004.03.008 |bibcode=2004STilR..79....7S |access-date=23 January 2022 }}</ref> Microaggregates (20–250&nbsp;μm) are ingested by soil mesofauna and fauna, and bacterial bodies are partly or totally digested in their guts.<ref>{{cite journal |last1=Saur |first1=Étienne |last2=Ponge |first2=Jean-François |year=1988 |title=Alimentary studies on the collembolan Paratullbergia callipygos using transmission electron microscopy |journal=Pedobiologia |volume=31 |issue=5/6 |pages=355–79 |doi=10.1016/S0031-4056(23)02274-6 |bibcode=1988Pedob..31..355S |url=https://www.academia.edu/52490540 |access-date=23 January 2022 }}</ref>

Humans impact soil formation by removing vegetation cover through [[tillage]], application of [[biocide]]s, fire and leaving soils bare. This can lead to erosion, waterlogging, lateritization or [[Podsolisation|podzolization]] (according to climate and topography).<ref>{{cite book |last=Oldeman |first=L. Roel |date=1992 |chapter=Global extent of soil degradation |title=ISRIC Bi-Annual Report 1991/1992 |publisher=[[ISRIC]] |location=Wageningen, The Netherlands |pages=19–36 |chapter-url=https://library.wur.nl/WebQuery/wurpubs/fulltext/299739 |access-date=23 January 2022 }}</ref> 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.<ref>{{cite journal |last1=Karathanasis |first1=Anastasios D. |last2=Wells |first2=Kenneth L. |year=2004 |title=A comparison of mineral weathering trends between two management systems on a catena of loess-derived soils |journal=[[Soil Science Society of America Journal]] |volume=53 |issue=2 |pages=582–88 |url=https://art1lib.org/book/23110084/bee731 |doi=10.2136/sssaj1989.03615995005300020047x |bibcode=1989SSASJ..53..582K |access-date=23 January 2022 }}</ref>

Earthworms, ants, termites, moles, gophers, as well as some millipedes and tenebrionid beetles, mix the soil as they burrow, significantly affecting soil formation.<ref name="Lee1991">{{cite journal |last1=Lee |first1=Kenneth Ernest |last2=Foster |first2=Ralph C. |year=2003 |title=Soil fauna and soil structure |journal=[[Australian Journal of Soil Research]] |volume=29 |issue=6 |pages=745–75 |doi=10.1071/SR9910745 |url=https://booksc.eu/book/23597797/35b543 |access-date=30 January 2022 }}</ref> Earthworms ingest soil particles and organic residues, enhancing the availability of plant nutrients in the material that passes through their bodies.<ref>{{cite journal |last=Scheu |first=Stefan |year=2003 |title=Effects of earthworms on plant growth: patterns and perspectives |journal=Pedobiologia |volume=47 |issue=5/6 |pages=846–56  |doi=10.1078/0031-4056-00270 |url=https://www.researchgate.net/publication/263041521 |access-date=30 January 2022 }}</ref> 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,<ref>{{cite journal |last1=Zhang |first1=Haiquan |last2=Schrader |first2=Stefan |year=1993 |title=Earthworm effects on selected physical and chemical properties of soil aggregates |journal=Biology and Fertility of Soils |volume=15 |issue=3 |pages=229–34 |doi=10.1007/BF00361617 |bibcode=1993BioFS..15..229Z |s2cid=24151632 |url=https://booksc.eu/book/5958409/e30980 |access-date=30 January 2022 }}</ref> thereby assuring ready infiltration of water.<ref>{{cite journal |last1=Bouché |first1=Marcel B. |last2=Al-Addan |first2=Fathel |year=1997 |title=Earthworms, water infiltration and soil stability: some new assessments |journal=[[Soil Biology and Biochemistry]] |volume=29 |issue=3/4 |pages=441–52 |doi=10.1016/S0038-0717(96)00272-6 |bibcode=1997SBiBi..29..441B |url=https://booksc.eu/book/17640626/e68038 |access-date=30 January 2022 }}</ref> As ants and termites build mounds, earthworms transport soil materials from one horizon to another.<ref>{{cite journal |last=Bernier |first=Nicolas |year=1998 |title=Earthworm feeding activity and development of the humus profile |journal=Biology and Fertility of Soils |volume=26 |issue=3 |pages=215–23 |doi=10.1007/s003740050370 |bibcode=1998BioFS..26..215B |s2cid=40478203 |url=https://www.academia.edu/34816078 |access-date=30 January 2022 }}</ref> Other important functions are fulfilled by earthworms in the soil ecosystem, in particular their intense [[mucus]] production, both within the intestine and as a lining in their galleries,<ref>{{cite journal |last=Scheu |first=Stefan |year=1991 |title=Mucus excretion and carbon turnover of endogeic earthworms |journal=Biology and Fertility of Soils |volume=12 |issue=3 |pages=217–20 |url=https://www.researchgate.net/publication/226748808 |doi=10.1007/BF00337206 |bibcode=1991BioFS..12..217S |s2cid=21931989 |access-date=30 January 2022 }}</ref> exert a [[Organic matter|priming effect]] on soil microflora,<ref>{{cite journal |last=Brown |first=George G. |year=1995 |title=How do earthworms affect microfloral and faunal community diversity? |journal=[[Plant and Soil]] |volume=170 |issue=1 |pages=209–31 |doi=10.1007/BF02183068 |bibcode=1995PlSoi.170..209B |s2cid=10254688 |url=https://booksc.eu/book/6863534/05b1df |access-date=30 January 2022 }}</ref> giving them the status of [[ecosystem engineer]]s, which they share with ants and termites.<ref>{{cite journal |last1=Jouquet |first1=Pascal |last2=Dauber |first2=Jens |last3=Lagerlöf |first3=Jan |last4=Lavelle |first4=Patrick |last5=Lepage |first5=Michel |year=2006 |title=Soil invertebrates as ecosystem engineers: intended and accidental effects on soil and feedback loops |journal=Applied Soil Ecology |volume=32 |issue=2 |pages=153–64 |url=https://www.academia.edu/50439505 |doi=10.1016/j.apsoil.2005.07.004 |bibcode=2006AppSE..32..153J |access-date=30 January 2022 }}</ref>

In general, the mixing of the soil by the activities of animals, sometimes called [[Perturbation (geology)|pedoturbation]], tends to undo or counteract the tendency of other soil-forming processes that create distinct horizons.<ref>{{cite journal |last1=Bohlen |first1=Patrick J. |last2=Scheu |first2=Stefan |last3=Hale |first3=Cindy M. |last4=McLean |first4=Mary Ann |last5=Migge |first5=Sonja |last6=Groffman |first6=Peter M. |last7=Parkinson |first7=Dennis |year=2004 |title=Non-native invasive earthworms as agents of change in northern temperate forests |journal=[[Frontiers in Ecology and the Environment]] |volume=2 |issue=8 |pages=427–35 |url=https://www.researchgate.net/publication/289148663 |doi=10.2307/3868431 |access-date=30 January 2022 |jstor=3868431 }}</ref> 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.<ref>{{cite journal |last1=De Bruyn |first1=Lisa Lobry |last2=Conacher |first2=Arthur J. |year=1990 |title=The role of termites and ants in soil modification: a review |journal=[[Australian Journal of Soil Research]] |volume=28 |issue=1 |pages=55–93 |url=https://www.researchgate.net/publication/248884324 |doi=10.1071/SR9900055 |bibcode=1990SoilR..28...55D |access-date=30 January 2022 }}</ref> Large animals such as gophers, moles, and prairie dogs bore into the lower soil horizons, bringing materials to the surface.<ref>{{cite web |url=https://ufdc.ufl.edu/UFE0017403/00001/pdf |last=Kinlaw |first=Alton Emory |title=Burrows of semi-fossorial vertebrates in upland communities of Central Florida: their architecture, dispersion and ecological consequences |pages=19–45 |year=2006 |access-date=30 January 2022 }}</ref> 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 ''crotovinas''.<ref>{{cite book |last=Borst |first=George |date=1968 |chapter=The occurrence of crotovinas in some southern California soils |title=Transactions of the 9th International Congress of Soil Science, Adelaide, Australia, August 5–15, 1968 |volume=2 |publisher=[[Angus & Robertson]] |location=Sydney, Australia |pages=19–27 |url=https://www.iuss.org/index.php?rex_media_type=download&rex_media_file=9th_international_congress_of_soil_science_transactions_volume_ii_compressed.pdf |access-date=30 January 2022 }}</ref>

Vegetation impacts soils in numerous ways. It can prevent erosion caused by excessive rain that might result from surface runoff.<ref>{{cite journal |last1=Gyssels |first1=Gwendolyn |last2=Poesen |first2=Jean |last3=Bochet |first3=Esther |last4=Li |first4=Yong |year=2005 |title=Impact of plant roots on the resistance of soils to erosion by water: a review |journal=[[Progress in Physical Geography]] |volume=29 |issue=2 |pages=189–217 |url=https://art1lib.org/book/23315291/89ee50 |doi=10.1191/0309133305pp443ra |bibcode=2005PrPG...29..189G |s2cid=55243167 |access-date=6 February 2022 }}</ref> Plants shade soils, keeping them cooler<ref>{{cite journal |last1=Balisky |first1=Allen C. |last2=Burton |first2=Philip J. |year=1993 |title=Distinction of soil thermal regimes under various experimental vegetation covers |journal=[[Canadian Journal of Soil Science]] |volume=73 |issue=4 |pages=411–20 |doi=10.4141/cjss93-043  |doi-access=free |bibcode=1993CaJSS..73..411B }}</ref> and slowing evaporation of [[soil moisture]].<ref>{{cite journal |last1=Marrou |first1=Hélène |last2=Dufour |first2=Lydie |last3=Wery |first3=Jacques |year=2013 |title=How does a shelter of solar panels influence water flows in a soil-crop system? |journal=European Journal of Agronomy |volume=50 |pages=38–51 |doi=10.1016/j.eja.2013.05.004 |bibcode=2013EuJAg..50...38M |url=https://art1lib.org/book/25051533/5113e5 |access-date=6 February 2022 }}</ref> Conversely, by way of [[transpiration]], plants can cause soils to lose moisture, resulting in complex and highly variable relationships between [[leaf area index]] (measuring light interception) and moisture loss: more generally plants prevent soil from [[desiccation]] during driest months while they dry it during moister months, thereby acting as a buffer against strong moisture variation.<ref>{{cite journal |last1=Heck |first1=Pamela |last2=Lüthi |first2=Daniel |last3=Schär |first3=Christoph |year=1999 |title=The influence of vegetation on the summertime evolution of European soil moisture |journal=Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere |volume=24 |issue=6 |pages=609–14 |url=https://art1lib.org/book/14341652/1fc870 |doi=10.1016/S1464-1909(99)00052-0 |bibcode=1999PCEB...24..609H |access-date=6 February 2022 }}</ref> Plants can form new chemicals that can break down minerals, both directly<ref>{{cite journal |last=Jones |first=David L. |year=1998 |title=Organic acids in the rhizospere: a critical review |journal=[[Plant and Soil]] |volume=205 |issue=1 |pages=25–44 |url=https://art1lib.org/book/10990607/f36bb8 |doi=10.1023/A:1004356007312 |bibcode=1998PlSoi.205...25J |s2cid=26813067 |access-date=6 February 2022 }}</ref> and indirectly through [[Mycorrhiza|mycorrhizal]] fungi<ref name="Landeweert2001" /> and rhizosphere bacteria,<ref>{{cite journal |last1=Calvaruso |first1=Christophe |last2=Turpault |first2=Marie-Pierre |last3=Frey-Klett |first3=Pascal |year=2006 |title=Root-associated bacteria contribute to mineral weathering and to mineral nutrition in trees: a budgeting analysis |journal=[[Applied and Environmental Microbiology]] |volume=72 |issue=2 |pages=1258–66  |doi=10.1128/AEM.72.2.1258-1266.2006 |pmid=16461674 |pmc=1392890 |bibcode=2006ApEnM..72.1258C }}</ref> and improve the soil structure.<ref>{{cite journal |last1=Angers |first1=Denis A. |last2=Caron |first2=Jean |year=1998 |title=Plant-induced changes in soil structure: processes and feedbacks |journal=Biogeochemistry |volume=42 |issue=1 |pages=55–72 |url=https://www.researchgate.net/publication/226938344 |doi=10.1023/A:1005944025343 |bibcode=1998Biogc..42...55A |s2cid=94249645 |access-date=6 February 2022 }}</ref> The type and amount of vegetation depend on climate, topography, soil characteristics and biological factors, mediated or not by human activities.<ref>{{cite journal |last1=Dai |first1=Shengpei |last2=Zhang |first2=Bo |last3=Wang |first3=Haijun |last4=Wang |first4=Yamin |last5=Guo |first5=Lingxia |last6=Wang |first6=Xingmei |last7=Li |first7=Dan |year=2011 |title=Vegetation cover change and the driving factors over northwest China |journal=Journal of Arid Land |volume=3 |issue=1 |pages=25–33 |url=https://www.researchgate.net/publication/228841309 |doi=10.3724/SP.J.1227.2011.00025 |doi-broken-date=11 November 2024 |access-date=6 February 2022 |doi-access=free |bibcode=2011JArL....3...25S }}</ref><ref>{{cite journal |last1=Vogiatzakis |first1=Ioannis |last2=Griffiths |first2=Geoffrey H. |last3=Mannion |first3=Antoinette M. |year=2003 |title=Environmental factors and vegetation composition, Lefka Ori Massif, Crete, S. Aegean |journal=[[Global Ecology and Biogeography]] |volume=12 |issue=2 |pages=131–46 |doi=10.1046/j.1466-822X.2003.00021.x  |url=https://art1lib.org/book/60423128/b47af0 |access-date=6 February 2022 |doi-access=free |bibcode=2003GloEB..12..131V }}</ref> Soil factors such as density, depth, chemistry, pH, temperature and moisture greatly 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.<ref>{{cite journal |last1=Brêthes |first1=Alain |last2=Brun |first2=Jean-Jacques |last3=Jabiol |first3=Bernard |last4=Ponge |first4=Jean-François |last5=Toutain |first5=François |year=1995 |title=Classification of forest humus forms: a French proposal |journal=Annales des Sciences Forestières |volume=52 |issue=6 |pages=535–46 |doi=10.1051/forest:19950602 |doi-access=free }}</ref>

The influence of humans, and by association, fire, are state factors placed within the organisms state factor.<ref>{{cite journal |url=https://art1lib.org/book/58287444/7c8785 |title=The place of humans in the state factor theory of ecosystems and their soils |last1=Amundson |first1=Ronald |last2=Jenny |first2=Hans |year=1991 |journal=Soil Science |volume=151 |issue=1 |pages=99–109 |doi=10.1097/00010694-199101000-00012 |bibcode=1991SoilS.151...99A |s2cid=95061311 |access-date=13 February 2022 }}</ref> Humans can import or extract nutrients and energy in ways that dramatically change soil formation. Accelerated soil erosion from [[overgrazing]], and [[Pre-Columbian]] [[terraforming]] the Amazon basin resulting in ''[[terra preta]]'' are two examples of the effects of human management.<ref>{{cite journal |last1=Ponge |first1=Jean-François |last2=Topoliantz |first2=Stéphanie |year=2005 |title=Charcoal consumption and casting activity by Pontoscolex corethurus (Glossoscolecidae) |url=https://www.researchgate.net/publication/44922028 |journal=Applied Soil Ecology |volume=28 |issue=3 |pages=217–24 |doi=10.1016/j.apsoil.2004.08.003 |bibcode=2005AppSE..28..217T |access-date=20 February 2022}}</ref>

It is believed that [[Native Americans in the United States|Native Americans]] regularly set fires to maintain several large areas of [[prairie]] grasslands in [[Indiana]] and [[Michigan]], although climate and mammalian [[Grazing (behaviour)|grazers]] (e.g. [[bisons]]) are also advocated to explain the maintenance of the [[Great Plains]] of North America.<ref>{{cite journal |last=Anderson |first=Roger C. |year=2006 |title=Evolution and origin of the Central Grassland of North America: climate, fire, and mammalian grazers |journal=[[Journal of the Torrey Botanical Society]] |volume=133 |issue=4 |pages=626–47 |url=https://www.academia.edu/6131302 |doi=10.3159/1095-5674(2006)133[626:EAOOTC]2.0.CO;2 |s2cid=13709954 |access-date=13 February 2022 |doi-access=free }}</ref> In more recent times, human destruction of natural vegetation and subsequent tillage of the soil for [[crop]] production has abruptly modified soil formation.<ref>{{cite journal |last1=Burke |first1=Ingrid C. |last2=Yonker |first2=Caroline M. |last3=Parton |first3=William J. |last4=Cole |first4=C. Vernon |last5=Flach |first5=Klaus |last6=Schimel |first6=David S. |year=1989 |title=Texture, climate, and cultivation effects on soil organic matter content in U.S. grassland soils |journal=[[Soil Science Society of America Journal]] |volume=53 |issue=3 |pages=800–05 |url=https://www.researchgate.net/publication/233209856 |doi=10.2136/sssaj1989.03615995005300030029x |access-date=13 February 2022 |bibcode=1989SSASJ..53..800B }}</ref> Likewise, irrigating soil in an arid region drastically influences soil-forming factors,<ref>{{cite journal |last1=Lisetskii |first1=Fedor N. |last2=Pichura |first2=Vitalii I. |year=2016 |title=Assessment and forecast of soil formation under irrigation in the steppe zone of Ukraine |journal=Russian Agricultural Sciences |volume=42 |issue=2 |pages=155–59 |url=http://dspace.bsu.edu.ru/bitstream/123456789/16324/1/Lisetskii_Assessment_Forecast_16_D.pdf |doi=10.3103/S1068367416020075 |bibcode=2016RuAgS..42..155L |s2cid=43356998 |access-date=13 February 2022 }}</ref> as does adding fertilizer and lime to soils of low fertility.<ref>{{cite web |url=https://stud.epsilon.slu.se/3263/1/schon_m_110919.pdf |last=Schön |first=Martina |title=Impact of N fertilization on subsoil properties: soil organic matter and aggregate stability |year=2011 |access-date=13 February 2022 }}</ref>

Distinct ecosystems produce distinct soils, sometimes in easily observable ways. For example, three species of [[land snail]]s in the genus ''[[Euchondrus]]'' in the [[Negev desert]] are noted for eating [[lichen]]s growing under the surface [[limestone]] rocks and slabs ([[endolithic]] lichens). The grazing activity of these ecosystem engineers disrupts the limestone, resulting in the weathering and the subsequent formation of soil.<ref name="Odling-Smee 2003">{{cite book |last1=Odling-Smee |first1=F. John |last2=Laland |first2=Kevin N. |last3=Feldman |first3=Marcus W. |year=2003 |chapter=Introduction |title=Niche construction: the neglected process in evolution |pages=7–8 |publisher=[[Princeton University Press]] |location=Princeton, New Jersey |isbn=978-0691044378 |chapter-url=https://fr.art1lib.org/book/79836470/bdd556 |doi=10.1515/9781400847266 |access-date=20 February 2022 |archive-date=17 June 2006 |archive-url=https://web.archive.org/web/20060617221931/http://www.pupress.princeton.edu/chapters/i7691.pdf |url-status=live }}</ref> 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 limestone in the Negev desert.<ref name="Odling-Smee 2003" />

The effects of ancient ecosystems are not as easily observed, and this challenges the understanding of soil formation. For example, the [[chernozem]]s of the North American tallgrass prairie have a humus fraction nearly half of which is [[charcoal]]. This outcome was not anticipated because the antecedent prairie [[fire ecology]] capable of producing these distinct deep rich black soils is not easily observed.<ref>{{cite journal |last1=Ponomarenko |first1=Elena V. |last2=Anderson |first2=Darwin W. |title=Importance of charred organic matter in Black Chernozem soils of Saskatchewan |year=2001 |journal=[[Canadian Journal of Soil Science]] |volume=81 |issue=3 |pages=285–297 |url=https://cdnsciencepub.com/doi/pdf/10.4141/S00-075 |quote=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 change in conceptual understanding (a paradigm shift) appears imminent. |doi=10.4141/S00-075 |bibcode=2001CaJSS..81..285P |access-date=20 February 2022 }}</ref>