Soil Ecology Wiki - User contributions [en]

Aggregate formation

2018-05-09T14:00:20Z

Amyschme: /* Microaggregates */

== '''Soil Aggregates''' ==

Soil aggregates are pieces or chunks of [[soil]] that bind together more tightly to one another due to a variety of factors. Certain soil particles bind together due to the activity of earthworms, fungal hyphae root exudes, and bacterial and fungal debris [1].[[File:aggregates.png|300px|thumb|left|Figure 1 [9] - soil aggregates attached to plant roots.]] The size of soil aggregates can vary across five degrees of magnitude [1], and the size of these aggregates affect porosity, water retention, soil organic material content, erosion, and available resources for microorganisms living in the soil [2].

[[File:aggregate-sizes.png|250px|thumb|right|Figure 2 - adapted from Fig. 1.9 [1] - soil aggregate sizing.]]

== Microaggregates ==

Microaggregates (< 250 um) are predominantly made from [[silt]] and [[clay]] and are held together by chemical charges (in the case of clay [3]) bacterial byproducts, and root exudes [4]. Earthworms have a large part in producing microaggregates through digestion of soil. They also unknowingly prepare these microaggregates to bind together via mucus from their gut to form macro aggregates [8]. Soil organic matter (vegetation), climate, composition, and management practices are responsible for forming macroaggregates [5].

== Macroaggregates ==

When plant roots penetrate the soil, they anchor chunks of soil together and help form macroaggregates. Macroaggregates (> 250 um) are typically formed in soils with high volumes of soil organic matter (SOM). [[File:Rootz.png|150px|thumb|left|Figure 3 [11] - Plant roots contribute to macroaggregate formation. ]] The breakdown of different types of detritus leads to a high diversity in the stages of SOM decomposition, which impacts the way aggregates form.[[File:USDA_aggregates.png|180px|thumb|right|Figure 4 [10] - the United States Department of Agriculture measures soil aggregate strength by placing aggregates in water held by metal mesh to determine how it will hold up in heavy rainfall. The soil aggregates to the left are more stable than the ones on the right. ]] Waxy organic material like pine needles, or OM that is high in lignin like oak leaves decompose slowly because of the complexity of their composition. In general, waxy detritus takes more time to form stable macroaggregates in comparison to litter that contains predominantly simpler compounds. The higher the level of organic matter decomposition, the larger and more stable the aggregates [4], and the more fertile the soil is. In general, soils with high SOM yield larger aggregates, which are more stable and less susceptible to erosion than smaller aggregates [6].

== Soil Moisture and Aggregate Stability ==

Environments with longer periods of time between drying and wetting tend to yield finer soil aggregates [7]. These soils are usually not as consistently productive as those found in locations with regular rainfall.
While the surface area of microaggregates is extensive, they are also more unstable than macroaggregates, and both are needed to maintain a healthy and productive soil. Microaggregates in topsoil are more prone to runoff in heavy rainfalls, while macroaggregates maintain soil stability [6]. Stable soils make for good agricultural yields because they do not crumble under rainfall, and instead retain water so that it is more available for root uptake [4]. The USDA measures soil stability by suspending aggregates in water for a certain length of time and observing if the aggregates maintain their structure or crumble after being submerged as shown in Figure 4 [10]. If they maintain their shape, it indicates a high level of soil organic matter and nutrient content and subsequent higher level of stability in agriculture [4]. Less stable (crumbly) soils are prone to erosion from wind and rainfall and do not usually maintain high levels of plant diversity.

==References==
[1] Coleman, David C., et al. ''Fundamentals of Soil Ecology''. Elsevier Academic Press, 2004.

[2] Spohn, Marie, and Luise Giani. “Impacts of Land Use Change on Soil Aggregation and Aggregate Stabilizing Compounds as Dependent on Time.” Soil Biology and Biochemistry, vol. 43, no. 5, 2011, pp. 1081–1088., doi:10.1016/j.soilbio.2011.01.029.

[3] Regelink, Inge C., et al. “Linkages between Aggregate Formation, Porosity and Soil Chemical Properties.” Geoderma, vol. 247-248, 2015, pp. 24–37., doi:10.1016/j.geoderma.2015.01.022.

[4] United States Department of Agriculture, and National Resource Conservation Service. “Soil Quality Indicators: Aggregate Stability.” Apr. 1996.

[5] Jastrow, J.d. “Soil Aggregate Formation and the Accrual of Particulate and Mineral-Associated Organic Matter.” Soil Biology and Biochemistry, vol. 28, no. 4-5, 1996, pp. 665–676., doi:10.1016/0038-0717(95)00159-x.

[6] Bensard, E., et al. “Fate of Particulate Organic Matter in Soil Aggregates during Cultivation.” European Journal of Soil Science, Wiley/Blackwell (10.1111), 10 Aug. 2005, onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.1996.tb01849.x/abstract.

[7] Semmel, H., et al. “The Dynamics of Soil Aggregate Formation and the Effect on Soil Physical Properties.” Soil Technology, vol. 3, no. 2, 1990, pp. 113–129., doi:10.1016/s0933-3630(05)80002-9.

[8] Six, Johan, and Keith Paustian. “Aggregate-Associated Soil Organic Matter as an Ecosystem Property and a Measurement Tool.” Soil Biology and Biochemistry, vol. 68, 2014, doi:10.1016/j.soilbio.2013.06.014.

[9] Jordan, Antonio. “Soil Aggregation - What Is Soil Structure?” Soil System Sciences, The European Geosciences Union, 19 Aug. 2013, blogs.egu.eu/divisions/sss/tag/soil-aggregation/.

[10]“Soil Organic Matter (Aggregate Stability).” USDA / NRCS, Natural Resources Conservation Service, www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054302.

[11] “Dave Leonard Tree Specialists.” Lexington Tree Service by Dave Leonard Tree Specialists - Emerald Ash Borer Treatment Experts, www.dlarborist.com/lawn-care.php.

Aggregate formation

2018-05-09T13:59:38Z

Amyschme: /* Soil Aggregates */

== '''Soil Aggregates''' ==

Soil aggregates are pieces or chunks of [[soil]] that bind together more tightly to one another due to a variety of factors. Certain soil particles bind together due to the activity of earthworms, fungal hyphae root exudes, and bacterial and fungal debris [1].[[File:aggregates.png|300px|thumb|left|Figure 1 [9] - soil aggregates attached to plant roots.]] The size of soil aggregates can vary across five degrees of magnitude [1], and the size of these aggregates affect porosity, water retention, soil organic material content, erosion, and available resources for microorganisms living in the soil [2].

[[File:aggregate-sizes.png|250px|thumb|right|Figure 2 - adapted from Fig. 1.9 [1] - soil aggregate sizing.]]

== Microaggregates ==

Microaggregates (< 250 um) are predominantly made from silt and clay and are held together by chemical charges (in the case of clay [3]) bacterial byproducts, and root exudes [4]. Earthworms have a large part in producing microaggregates through digestion of soil. They also unknowingly prepare these microaggregates to bind together via mucus from their gut to form macro aggregates [8]. Soil organic matter (vegetation), climate, composition, and management practices are responsible for forming macroaggregates [5].

== Macroaggregates ==

When plant roots penetrate the soil, they anchor chunks of soil together and help form macroaggregates. Macroaggregates (> 250 um) are typically formed in soils with high volumes of soil organic matter (SOM). [[File:Rootz.png|150px|thumb|left|Figure 3 [11] - Plant roots contribute to macroaggregate formation. ]] The breakdown of different types of detritus leads to a high diversity in the stages of SOM decomposition, which impacts the way aggregates form.[[File:USDA_aggregates.png|180px|thumb|right|Figure 4 [10] - the United States Department of Agriculture measures soil aggregate strength by placing aggregates in water held by metal mesh to determine how it will hold up in heavy rainfall. The soil aggregates to the left are more stable than the ones on the right. ]] Waxy organic material like pine needles, or OM that is high in lignin like oak leaves decompose slowly because of the complexity of their composition. In general, waxy detritus takes more time to form stable macroaggregates in comparison to litter that contains predominantly simpler compounds. The higher the level of organic matter decomposition, the larger and more stable the aggregates [4], and the more fertile the soil is. In general, soils with high SOM yield larger aggregates, which are more stable and less susceptible to erosion than smaller aggregates [6].

== Soil Moisture and Aggregate Stability ==

Environments with longer periods of time between drying and wetting tend to yield finer soil aggregates [7]. These soils are usually not as consistently productive as those found in locations with regular rainfall.
While the surface area of microaggregates is extensive, they are also more unstable than macroaggregates, and both are needed to maintain a healthy and productive soil. Microaggregates in topsoil are more prone to runoff in heavy rainfalls, while macroaggregates maintain soil stability [6]. Stable soils make for good agricultural yields because they do not crumble under rainfall, and instead retain water so that it is more available for root uptake [4]. The USDA measures soil stability by suspending aggregates in water for a certain length of time and observing if the aggregates maintain their structure or crumble after being submerged as shown in Figure 4 [10]. If they maintain their shape, it indicates a high level of soil organic matter and nutrient content and subsequent higher level of stability in agriculture [4]. Less stable (crumbly) soils are prone to erosion from wind and rainfall and do not usually maintain high levels of plant diversity.

==References==
[1] Coleman, David C., et al. ''Fundamentals of Soil Ecology''. Elsevier Academic Press, 2004.

[2] Spohn, Marie, and Luise Giani. “Impacts of Land Use Change on Soil Aggregation and Aggregate Stabilizing Compounds as Dependent on Time.” Soil Biology and Biochemistry, vol. 43, no. 5, 2011, pp. 1081–1088., doi:10.1016/j.soilbio.2011.01.029.

[3] Regelink, Inge C., et al. “Linkages between Aggregate Formation, Porosity and Soil Chemical Properties.” Geoderma, vol. 247-248, 2015, pp. 24–37., doi:10.1016/j.geoderma.2015.01.022.

[4] United States Department of Agriculture, and National Resource Conservation Service. “Soil Quality Indicators: Aggregate Stability.” Apr. 1996.

[5] Jastrow, J.d. “Soil Aggregate Formation and the Accrual of Particulate and Mineral-Associated Organic Matter.” Soil Biology and Biochemistry, vol. 28, no. 4-5, 1996, pp. 665–676., doi:10.1016/0038-0717(95)00159-x.

[6] Bensard, E., et al. “Fate of Particulate Organic Matter in Soil Aggregates during Cultivation.” European Journal of Soil Science, Wiley/Blackwell (10.1111), 10 Aug. 2005, onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.1996.tb01849.x/abstract.

[7] Semmel, H., et al. “The Dynamics of Soil Aggregate Formation and the Effect on Soil Physical Properties.” Soil Technology, vol. 3, no. 2, 1990, pp. 113–129., doi:10.1016/s0933-3630(05)80002-9.

[8] Six, Johan, and Keith Paustian. “Aggregate-Associated Soil Organic Matter as an Ecosystem Property and a Measurement Tool.” Soil Biology and Biochemistry, vol. 68, 2014, doi:10.1016/j.soilbio.2013.06.014.

[9] Jordan, Antonio. “Soil Aggregation - What Is Soil Structure?” Soil System Sciences, The European Geosciences Union, 19 Aug. 2013, blogs.egu.eu/divisions/sss/tag/soil-aggregation/.

[10]“Soil Organic Matter (Aggregate Stability).” USDA / NRCS, Natural Resources Conservation Service, www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054302.

[11] “Dave Leonard Tree Specialists.” Lexington Tree Service by Dave Leonard Tree Specialists - Emerald Ash Borer Treatment Experts, www.dlarborist.com/lawn-care.php.

Soil organisms

2018-05-08T23:59:13Z

Amyschme: /* Microfauna */

= '''Microfauna''' =
[[File: Protists.png|280px|thumb|left|Figure 1 [1] - adapted from Figure 4.5 - "Morphology of four types of soil protozoa: (a) flagellate (Bodo); (b) naked amoeba (Naegleria); (c) testacean (Hyalosphenia); (d) ciliate (Oxytricha) (from Lousier and Bamforth, 1990)."]]
Microfauna are organisms that are microscopic in size, and a high-power microscope is needed to observe and identify them. Protists are predominantly unicellular organisms that are the most abundant of the microfauna in soils. There are four main types of soil proists: flagellates, naked amoeba, ciliates and testacea (Figure 1).
===Flagellates===
Flagellates can be identified by their flagella (a whip-like swimming appendage) and prey mostly on bacteria. Because of their diet, flagellates play a large role in nutrient turnover [1].
[[File:Naked_amoeba.jpg|200px|thumb|right|Figure 2 [2] - a naked amoeba engulfing its prey (phagocytosis)]]

===Naked Amoebae===
Naked amoebae are phagotrophic, meaning they engulf their prey (Figure 2) including bacteria, fungi, algae, and other organic particulates [1].

===Testacea===
Testacea, or testate amoebae, are similar to naked amoeba but less abundant and have a shell called a “test” giving it its name. Although most protists are considered cosmopolitan, testate amoebae vary widely by geographical region [3].

===Ciliates===
[[Ciliates]] are organisms that are covered with cilia, a mechanism for transportation. They are found in exclusively moist environments, but this can range from Antarctic ice to hot springs to wetlands [4].

='''Mesofauna and Macrofauna'''=
==''Lophotrochozoa''==
Lophotrochozoans are protostomes that have a lophophore, or a "mouth" surrounded by cilia for feeding. Lophotrochozoans include flatworms, [[rotifers]], [[annelids]], and mollusks.
[[File:Rotifera.png|220px|thumb|right|Figure 3 [6] - Rotifera]]

===Rotifera===
[[rotifers|Rotifera]] are microscopic (or nearly microscopic) organisms that exist in predominantly wet environments. In soils, they inhabit thin films of water surrounding soil particles and [[aggregate formation| aggregates]]. They can also be found in puddles and on mosses surrounding decomposing trees [5]. Rotifers feed on bacteria, algae, and other protists by using the cilia near their mouths to create a water current in which prey is caught (Figure 3), making them important bottom-level consumers.

===Annelida===
[[Annelids]] are a phyla of segmented worms divided traditionally into Clitellata (including earthworms and leeches) and Polychaeta (mostly marine worms)[12]. Polychaetes, or bristle worms, have multiple "hairs" (chetae) made from chitin on their segments. Clitellata are hermaphroditic segmented worms that have a reproductive organ which wraps around their bodies called the clitellum. This organ holds and nourishes fertilized eggs until they hatch.
[[File:Nematoda.png|150px|thumb|left|Figure 4 [9] - Nematoda ]]

==''Ecdysozoa''==
Ecysozoans are organisms that have a chitin exoskeleton, including [[nematodes|roundworms]], [[tardigrades]] and arthropods.

===Nematoda===
[[Nematodes]], also known as roundworms, are perhaps the most abundant of the mesofauna in soils. The invertibrates have an overall tube-like cylindrical shape which tapers at both ends (Figure 4) [1]. Nematodes can consume prey up to ten times the size of their mouths. They predominantly prey on root hairs, roots, and fungal hyphae [7]. Some entomopathogenic nematodes (those which act as insect parasites) can infect and kill a root-feeding host while producing more than 400,000 offspring (in the case of the large ghost mouth caterpillar) (Figure 4) [1,8].

===Tardigrada===
[[Tardigrades]] are small (500um) organisms that can exist in nearly any environment. [[File:Tardigrade.JPG|200px|thumb|right|Figure 5 [10] - Tardigrade ]] Colloquially called "water bears" for their resemblance to the land-dwelling mammal, these organisms possess the ability to enter a cryptobiotic (near lifeless) state if conditions are unfavorable [10]. Tardigrades serve as a warning sign for environmental stress [1]. These organisms feed on bits of algae and particulate organic matter.

===Arthropoda===
[[File:Millipedes.png|200px|thumb|left|Figure 7 [1] - millipedes - adapted from Figure 4.42 ]]
Arthropods, like all ecysozoans, are organisms with a hard exoskeleton and encompass [[isopods]], myriapods, [[springtail|collembola]], and [[mites]]. Isopods are wide, flat organisms with segmented bodies that feeds on roots, leaves, and detritus. They have jointed appendages and a mandible built to cut leaves for consumption. Due to their susceptibility to desiccation, many have adapted by developing the capability to purify their own urine to reabsorb it [1]. They may also roll into a ball if threatened, which allows them to capitalize on their hard exterior, giving them their more common name, "rolly pollies" or "pill bugs." (Figure 6) [[File:Isopods.png|150px|thumb|right|Figure 6 [1] - isopods - adapted from Figure 4.40]]

Myriapoda include all mesofauna with long bodies and many legs like millipedes (Diplopoda) and centipedes (Chilopoda)[11]. While millipedes (Figure 7) are detritivores, centipedes are carnivorous with pincer-like fangs that feed mostly on other small organisms like collembolans.

='''References'''=
[1] Coleman, David C., et al. Fundamentals of Soil Ecology. Elsevier Academic Press, 2004.

[2] Burns, Keanna. “Otherworldly Amoebas.” Future Science Leaders, 31 July 2014, www.futurescienceleaders.com/mariecurious/2014/02/03/otherworldly-amoebas/.

[3] Smith, Humphrey Graham, et al. “Diversity and Biogeography of Testate Amoebae.” Protist Diversity and Geographical Distribution Topics in Biodiversity and Conservation, 2007, pp. 95–109., doi:10.1007/978-90-481-2801-3_8.

[4] Lynn, Denis H. “Ciliophora.” Encyclopedia of Life Sciences, 16 Apr. 2012, doi:10.1002/9780470015902.a0001966.pub3.

[5] Wallace, Robert Lee, and Hillary April Smith. “Rotifera.” Encyclopedia of Life Sciences, vol. 1, 15 May 2013, doi:10.1038/npg.els.0001588.

[6] Howey, Richard L. “The Wonderfully Weird World of Rotifers.” Micscape Microscopy and Microscope Magazine, 1999, www.microscopy-uk.org.uk/mag/indexmag.html?http%3A%2F%2Fwww.microscopy-uk.org.uk%2Fmag%2Fartnov99%2Frotih.html.

[7] Poinar, George. “Nematoda (Roundworms).” Encyclopedia of Life Sciences, 15 May 2012, doi:10.1002/9780470015902.a0001593.pub3.

[8] Strong, D. R., et al. “Entomopathogenic Nematodes: Natural Enemies of Root-Feeding Caterpillars on Bush Lupine.” Oecologia, vol. 108, no. 1, 1996, pp. 167–173., doi:10.1007/bf00333228.

[9] “Marine Nematodes Get New Digs!” National Museum of Natural History Unearthed, 21 Sept. 2015, nmnh.typepad.com/no_bones/2015/09/marine-nematodes-get-new-digs.html.

[10] Miller, W. R. (2011). Tardigrades. American Scientist, 99(5), 384–391. https://doi.org/10.1511/2011.92.384

[11] Wright, Jonathan C. “Myriapoda (Including Centipedes and Millipedes).” Encyclopedia of Life Sciences, Oct. 2012, www.els.net/WileyCDA/ElsArticle/refId-a0001607.html.

[12] Struck, Torsten H, et al. “Annelid Phylogeny and the Status of Sipuncula and Echiura.” BMC Evolutionary Biology, vol. 7, no. 1, 2007, p. 57., doi:10.1186/1471-2148-7-57.

Soil organisms

2018-05-08T23:58:52Z

Amyschme: /* Naked Amoebae */

= '''Microfauna''' =
[[File: Protists.png|280px|thumb|left|Figure 1 [1] - adapted from Figure 4.5 - "Morphology of four types of soil protozoa: (a) flagellate (Bodo); (b) naked amoeba (Naegleria); (c) testacean (Hyalosphenia); (d) ciliate (Oxytricha) (from Lousier and Bamforth, 1990)."]]
Microfauna are organisms that are microscopic in size, and a high-power microscope is needed to observe and identify them. Protists are predominantly unicellular organisms that are the most abundant of the microfauna in soils. There are four main types of soil proists: flagellates, naked amoeba, ciliates and testacea (Figure 1[1]).
===Flagellates===
Flagellates can be identified by their flagella (a whip-like swimming appendage) and prey mostly on bacteria. Because of their diet, flagellates play a large role in nutrient turnover [1].
[[File:Naked_amoeba.jpg|200px|thumb|right|Figure 2 [2] - a naked amoeba engulfing its prey (phagocytosis)]]

===Naked Amoebae===
Naked amoebae are phagotrophic, meaning they engulf their prey (Figure 2) including bacteria, fungi, algae, and other organic particulates [1].

===Testacea===
Testacea, or testate amoebae, are similar to naked amoeba but less abundant and have a shell called a “test” giving it its name. Although most protists are considered cosmopolitan, testate amoebae vary widely by geographical region [3].

===Ciliates===
[[Ciliates]] are organisms that are covered with cilia, a mechanism for transportation. They are found in exclusively moist environments, but this can range from Antarctic ice to hot springs to wetlands [4].

='''Mesofauna and Macrofauna'''=
==''Lophotrochozoa''==
Lophotrochozoans are protostomes that have a lophophore, or a "mouth" surrounded by cilia for feeding. Lophotrochozoans include flatworms, [[rotifers]], [[annelids]], and mollusks.
[[File:Rotifera.png|220px|thumb|right|Figure 3 [6] - Rotifera]]

===Rotifera===
[[rotifers|Rotifera]] are microscopic (or nearly microscopic) organisms that exist in predominantly wet environments. In soils, they inhabit thin films of water surrounding soil particles and [[aggregate formation| aggregates]]. They can also be found in puddles and on mosses surrounding decomposing trees [5]. Rotifers feed on bacteria, algae, and other protists by using the cilia near their mouths to create a water current in which prey is caught (Figure 3), making them important bottom-level consumers.

===Annelida===
[[Annelids]] are a phyla of segmented worms divided traditionally into Clitellata (including earthworms and leeches) and Polychaeta (mostly marine worms)[12]. Polychaetes, or bristle worms, have multiple "hairs" (chetae) made from chitin on their segments. Clitellata are hermaphroditic segmented worms that have a reproductive organ which wraps around their bodies called the clitellum. This organ holds and nourishes fertilized eggs until they hatch.
[[File:Nematoda.png|150px|thumb|left|Figure 4 [9] - Nematoda ]]

==''Ecdysozoa''==
Ecysozoans are organisms that have a chitin exoskeleton, including [[nematodes|roundworms]], [[tardigrades]] and arthropods.

===Nematoda===
[[Nematodes]], also known as roundworms, are perhaps the most abundant of the mesofauna in soils. The invertibrates have an overall tube-like cylindrical shape which tapers at both ends (Figure 4) [1]. Nematodes can consume prey up to ten times the size of their mouths. They predominantly prey on root hairs, roots, and fungal hyphae [7]. Some entomopathogenic nematodes (those which act as insect parasites) can infect and kill a root-feeding host while producing more than 400,000 offspring (in the case of the large ghost mouth caterpillar) (Figure 4) [1,8].

===Tardigrada===
[[Tardigrades]] are small (500um) organisms that can exist in nearly any environment. [[File:Tardigrade.JPG|200px|thumb|right|Figure 5 [10] - Tardigrade ]] Colloquially called "water bears" for their resemblance to the land-dwelling mammal, these organisms possess the ability to enter a cryptobiotic (near lifeless) state if conditions are unfavorable [10]. Tardigrades serve as a warning sign for environmental stress [1]. These organisms feed on bits of algae and particulate organic matter.

===Arthropoda===
[[File:Millipedes.png|200px|thumb|left|Figure 7 [1] - millipedes - adapted from Figure 4.42 ]]
Arthropods, like all ecysozoans, are organisms with a hard exoskeleton and encompass [[isopods]], myriapods, [[springtail|collembola]], and [[mites]]. Isopods are wide, flat organisms with segmented bodies that feeds on roots, leaves, and detritus. They have jointed appendages and a mandible built to cut leaves for consumption. Due to their susceptibility to desiccation, many have adapted by developing the capability to purify their own urine to reabsorb it [1]. They may also roll into a ball if threatened, which allows them to capitalize on their hard exterior, giving them their more common name, "rolly pollies" or "pill bugs." (Figure 6) [[File:Isopods.png|150px|thumb|right|Figure 6 [1] - isopods - adapted from Figure 4.40]]

Myriapoda include all mesofauna with long bodies and many legs like millipedes (Diplopoda) and centipedes (Chilopoda)[11]. While millipedes (Figure 7) are detritivores, centipedes are carnivorous with pincer-like fangs that feed mostly on other small organisms like collembolans.

='''References'''=
[1] Coleman, David C., et al. Fundamentals of Soil Ecology. Elsevier Academic Press, 2004.

[2] Burns, Keanna. “Otherworldly Amoebas.” Future Science Leaders, 31 July 2014, www.futurescienceleaders.com/mariecurious/2014/02/03/otherworldly-amoebas/.

[3] Smith, Humphrey Graham, et al. “Diversity and Biogeography of Testate Amoebae.” Protist Diversity and Geographical Distribution Topics in Biodiversity and Conservation, 2007, pp. 95–109., doi:10.1007/978-90-481-2801-3_8.

[4] Lynn, Denis H. “Ciliophora.” Encyclopedia of Life Sciences, 16 Apr. 2012, doi:10.1002/9780470015902.a0001966.pub3.

[5] Wallace, Robert Lee, and Hillary April Smith. “Rotifera.” Encyclopedia of Life Sciences, vol. 1, 15 May 2013, doi:10.1038/npg.els.0001588.

[6] Howey, Richard L. “The Wonderfully Weird World of Rotifers.” Micscape Microscopy and Microscope Magazine, 1999, www.microscopy-uk.org.uk/mag/indexmag.html?http%3A%2F%2Fwww.microscopy-uk.org.uk%2Fmag%2Fartnov99%2Frotih.html.

[7] Poinar, George. “Nematoda (Roundworms).” Encyclopedia of Life Sciences, 15 May 2012, doi:10.1002/9780470015902.a0001593.pub3.

[8] Strong, D. R., et al. “Entomopathogenic Nematodes: Natural Enemies of Root-Feeding Caterpillars on Bush Lupine.” Oecologia, vol. 108, no. 1, 1996, pp. 167–173., doi:10.1007/bf00333228.

[9] “Marine Nematodes Get New Digs!” National Museum of Natural History Unearthed, 21 Sept. 2015, nmnh.typepad.com/no_bones/2015/09/marine-nematodes-get-new-digs.html.

[10] Miller, W. R. (2011). Tardigrades. American Scientist, 99(5), 384–391. https://doi.org/10.1511/2011.92.384

[11] Wright, Jonathan C. “Myriapoda (Including Centipedes and Millipedes).” Encyclopedia of Life Sciences, Oct. 2012, www.els.net/WileyCDA/ElsArticle/refId-a0001607.html.

[12] Struck, Torsten H, et al. “Annelid Phylogeny and the Status of Sipuncula and Echiura.” BMC Evolutionary Biology, vol. 7, no. 1, 2007, p. 57., doi:10.1186/1471-2148-7-57.

Soil organisms

2018-05-08T23:56:53Z

Amyschme: /* Arthropoda */

= '''Microfauna''' =
[[File: Protists.png|280px|thumb|left|Figure 1 [1] - adapted from Figure 4.5 - "Morphology of four types of soil protozoa: (a) flagellate (Bodo); (b) naked amoeba (Naegleria); (c) testacean (Hyalosphenia); (d) ciliate (Oxytricha) (from Lousier and Bamforth, 1990)."]]
Microfauna are organisms that are microscopic in size, and a high-power microscope is needed to observe and identify them. Protists are predominantly unicellular organisms that are the most abundant of the microfauna in soils. There are four main types of soil proists: flagellates, naked amoeba, ciliates and testacea (Figure 1[1]).
===Flagellates===
Flagellates can be identified by their flagella (a whip-like swimming appendage) and prey mostly on bacteria. Because of their diet, flagellates play a large role in nutrient turnover [1].
[[File:Naked_amoeba.jpg|200px|thumb|right|Figure 2 [2] - a naked amoeba engulfing its prey (phagocytosis)]]

===Naked Amoebae===
Naked amoebae are phagotrophic, meaning they engulf their prey (Figure 2[2]) including bacteria, fungi, algae, and other organic particulates [1].

===Testacea===
Testacea, or testate amoebae, are similar to naked amoeba but less abundant and have a shell called a “test” giving it its name. Although most protists are considered cosmopolitan, testate amoebae vary widely by geographical region [3].

===Ciliates===
[[Ciliates]] are organisms that are covered with cilia, a mechanism for transportation. They are found in exclusively moist environments, but this can range from Antarctic ice to hot springs to wetlands [4].

='''Mesofauna and Macrofauna'''=
==''Lophotrochozoa''==
Lophotrochozoans are protostomes that have a lophophore, or a "mouth" surrounded by cilia for feeding. Lophotrochozoans include flatworms, [[rotifers]], [[annelids]], and mollusks.
[[File:Rotifera.png|220px|thumb|right|Figure 3 [6] - Rotifera]]

===Rotifera===
[[rotifers|Rotifera]] are microscopic (or nearly microscopic) organisms that exist in predominantly wet environments. In soils, they inhabit thin films of water surrounding soil particles and [[aggregate formation| aggregates]]. They can also be found in puddles and on mosses surrounding decomposing trees [5]. Rotifers feed on bacteria, algae, and other protists by using the cilia near their mouths to create a water current in which prey is caught (Figure 3), making them important bottom-level consumers.

===Annelida===
[[Annelids]] are a phyla of segmented worms divided traditionally into Clitellata (including earthworms and leeches) and Polychaeta (mostly marine worms)[12]. Polychaetes, or bristle worms, have multiple "hairs" (chetae) made from chitin on their segments. Clitellata are hermaphroditic segmented worms that have a reproductive organ which wraps around their bodies called the clitellum. This organ holds and nourishes fertilized eggs until they hatch.
[[File:Nematoda.png|150px|thumb|left|Figure 4 [9] - Nematoda ]]

==''Ecdysozoa''==
Ecysozoans are organisms that have a chitin exoskeleton, including [[nematodes|roundworms]], [[tardigrades]] and arthropods.

===Nematoda===
[[Nematodes]], also known as roundworms, are perhaps the most abundant of the mesofauna in soils. The invertibrates have an overall tube-like cylindrical shape which tapers at both ends (Figure 4) [1]. Nematodes can consume prey up to ten times the size of their mouths. They predominantly prey on root hairs, roots, and fungal hyphae [7]. Some entomopathogenic nematodes (those which act as insect parasites) can infect and kill a root-feeding host while producing more than 400,000 offspring (in the case of the large ghost mouth caterpillar) (Figure 4) [1,8].

===Tardigrada===
[[Tardigrades]] are small (500um) organisms that can exist in nearly any environment. [[File:Tardigrade.JPG|200px|thumb|right|Figure 5 [10] - Tardigrade ]] Colloquially called "water bears" for their resemblance to the land-dwelling mammal, these organisms possess the ability to enter a cryptobiotic (near lifeless) state if conditions are unfavorable [10]. Tardigrades serve as a warning sign for environmental stress [1]. These organisms feed on bits of algae and particulate organic matter.

===Arthropoda===
[[File:Millipedes.png|200px|thumb|left|Figure 7 [1] - millipedes - adapted from Figure 4.42 ]]
Arthropods, like all ecysozoans, are organisms with a hard exoskeleton and encompass [[isopods]], myriapods, [[springtail|collembola]], and [[mites]]. Isopods are wide, flat organisms with segmented bodies that feeds on roots, leaves, and detritus. They have jointed appendages and a mandible built to cut leaves for consumption. Due to their susceptibility to desiccation, many have adapted by developing the capability to purify their own urine to reabsorb it [1]. They may also roll into a ball if threatened, which allows them to capitalize on their hard exterior, giving them their more common name, "rolly pollies" or "pill bugs." (Figure 6) [[File:Isopods.png|150px|thumb|right|Figure 6 [1] - isopods - adapted from Figure 4.40]]

Myriapoda include all mesofauna with long bodies and many legs like millipedes (Diplopoda) and centipedes (Chilopoda)[11]. While millipedes (Figure 7) are detritivores, centipedes are carnivorous with pincer-like fangs that feed mostly on other small organisms like collembolans.

='''References'''=
[1] Coleman, David C., et al. Fundamentals of Soil Ecology. Elsevier Academic Press, 2004.

[2] Burns, Keanna. “Otherworldly Amoebas.” Future Science Leaders, 31 July 2014, www.futurescienceleaders.com/mariecurious/2014/02/03/otherworldly-amoebas/.

[3] Smith, Humphrey Graham, et al. “Diversity and Biogeography of Testate Amoebae.” Protist Diversity and Geographical Distribution Topics in Biodiversity and Conservation, 2007, pp. 95–109., doi:10.1007/978-90-481-2801-3_8.

[4] Lynn, Denis H. “Ciliophora.” Encyclopedia of Life Sciences, 16 Apr. 2012, doi:10.1002/9780470015902.a0001966.pub3.

[5] Wallace, Robert Lee, and Hillary April Smith. “Rotifera.” Encyclopedia of Life Sciences, vol. 1, 15 May 2013, doi:10.1038/npg.els.0001588.

[6] Howey, Richard L. “The Wonderfully Weird World of Rotifers.” Micscape Microscopy and Microscope Magazine, 1999, www.microscopy-uk.org.uk/mag/indexmag.html?http%3A%2F%2Fwww.microscopy-uk.org.uk%2Fmag%2Fartnov99%2Frotih.html.

[7] Poinar, George. “Nematoda (Roundworms).” Encyclopedia of Life Sciences, 15 May 2012, doi:10.1002/9780470015902.a0001593.pub3.

[8] Strong, D. R., et al. “Entomopathogenic Nematodes: Natural Enemies of Root-Feeding Caterpillars on Bush Lupine.” Oecologia, vol. 108, no. 1, 1996, pp. 167–173., doi:10.1007/bf00333228.

[9] “Marine Nematodes Get New Digs!” National Museum of Natural History Unearthed, 21 Sept. 2015, nmnh.typepad.com/no_bones/2015/09/marine-nematodes-get-new-digs.html.

[10] Miller, W. R. (2011). Tardigrades. American Scientist, 99(5), 384–391. https://doi.org/10.1511/2011.92.384

[11] Wright, Jonathan C. “Myriapoda (Including Centipedes and Millipedes).” Encyclopedia of Life Sciences, Oct. 2012, www.els.net/WileyCDA/ElsArticle/refId-a0001607.html.

[12] Struck, Torsten H, et al. “Annelid Phylogeny and the Status of Sipuncula and Echiura.” BMC Evolutionary Biology, vol. 7, no. 1, 2007, p. 57., doi:10.1186/1471-2148-7-57.

Soil organisms

2018-05-08T23:55:27Z

Amyschme: Created page with "= '''Microfauna''' = [[File: Protists.png|280px|thumb|left|Figure 1 [1] - adapted from Figure 4.5 - "Morphology of four types of soil protozoa: (a) flagellate (Bodo); (b) nake..."

= '''Microfauna''' =
[[File: Protists.png|280px|thumb|left|Figure 1 [1] - adapted from Figure 4.5 - "Morphology of four types of soil protozoa: (a) flagellate (Bodo); (b) naked amoeba (Naegleria); (c) testacean (Hyalosphenia); (d) ciliate (Oxytricha) (from Lousier and Bamforth, 1990)."]]
Microfauna are organisms that are microscopic in size, and a high-power microscope is needed to observe and identify them. Protists are predominantly unicellular organisms that are the most abundant of the microfauna in soils. There are four main types of soil proists: flagellates, naked amoeba, ciliates and testacea (Figure 1[1]).
===Flagellates===
Flagellates can be identified by their flagella (a whip-like swimming appendage) and prey mostly on bacteria. Because of their diet, flagellates play a large role in nutrient turnover [1].
[[File:Naked_amoeba.jpg|200px|thumb|right|Figure 2 [2] - a naked amoeba engulfing its prey (phagocytosis)]]

===Naked Amoebae===
Naked amoebae are phagotrophic, meaning they engulf their prey (Figure 2[2]) including bacteria, fungi, algae, and other organic particulates [1].

===Testacea===
Testacea, or testate amoebae, are similar to naked amoeba but less abundant and have a shell called a “test” giving it its name. Although most protists are considered cosmopolitan, testate amoebae vary widely by geographical region [3].

===Ciliates===
[[Ciliates]] are organisms that are covered with cilia, a mechanism for transportation. They are found in exclusively moist environments, but this can range from Antarctic ice to hot springs to wetlands [4].

='''Mesofauna and Macrofauna'''=
==''Lophotrochozoa''==
Lophotrochozoans are protostomes that have a lophophore, or a "mouth" surrounded by cilia for feeding. Lophotrochozoans include flatworms, [[rotifers]], [[annelids]], and mollusks.
[[File:Rotifera.png|220px|thumb|right|Figure 3 [6] - Rotifera]]

===Rotifera===
[[rotifers|Rotifera]] are microscopic (or nearly microscopic) organisms that exist in predominantly wet environments. In soils, they inhabit thin films of water surrounding soil particles and [[aggregate formation| aggregates]]. They can also be found in puddles and on mosses surrounding decomposing trees [5]. Rotifers feed on bacteria, algae, and other protists by using the cilia near their mouths to create a water current in which prey is caught (Figure 3), making them important bottom-level consumers.

===Annelida===
[[Annelids]] are a phyla of segmented worms divided traditionally into Clitellata (including earthworms and leeches) and Polychaeta (mostly marine worms)[12]. Polychaetes, or bristle worms, have multiple "hairs" (chetae) made from chitin on their segments. Clitellata are hermaphroditic segmented worms that have a reproductive organ which wraps around their bodies called the clitellum. This organ holds and nourishes fertilized eggs until they hatch.
[[File:Nematoda.png|150px|thumb|left|Figure 4 [9] - Nematoda ]]

==''Ecdysozoa''==
Ecysozoans are organisms that have a chitin exoskeleton, including [[nematodes|roundworms]], [[tardigrades]] and arthropods.

===Nematoda===
[[Nematodes]], also known as roundworms, are perhaps the most abundant of the mesofauna in soils. The invertibrates have an overall tube-like cylindrical shape which tapers at both ends (Figure 4) [1]. Nematodes can consume prey up to ten times the size of their mouths. They predominantly prey on root hairs, roots, and fungal hyphae [7]. Some entomopathogenic nematodes (those which act as insect parasites) can infect and kill a root-feeding host while producing more than 400,000 offspring (in the case of the large ghost mouth caterpillar) (Figure 4) [1,8].

===Tardigrada===
[[Tardigrades]] are small (500um) organisms that can exist in nearly any environment. [[File:Tardigrade.JPG|200px|thumb|right|Figure 5 [10] - Tardigrade ]] Colloquially called "water bears" for their resemblance to the land-dwelling mammal, these organisms possess the ability to enter a cryptobiotic (near lifeless) state if conditions are unfavorable [10]. Tardigrades serve as a warning sign for environmental stress [1]. These organisms feed on bits of algae and particulate organic matter.

===Arthropoda===
[[File:Millipedes.png|200px|thumb|left|Figure 7 [1] - millipedes - adapted from Figure 4.42 ]]
Arthropods, like all ecysozoans, are organisms with a hard exoskeleton and encompass [[isopods]], myriapods, [[springtails|collembola]], and [[mites]]. Isopods are wide, flat organisms with segmented bodies that feeds on roots, leaves, and detritus. They have jointed appendages and a mandible built to cut leaves for consumption. Due to their susceptibility to desiccation, many have adapted by developing the capability to purify their own urine to reabsorb it [1]. They may also roll into a ball if threatened, which allows them to capitalize on their hard exterior, giving them their more common name, "rolly pollies" or "pill bugs." (Figure 6) [[File:Isopods.png|150px|thumb|right|Figure 6 [1] - isopods - adapted from Figure 4.40]]

Myriapoda include all mesofauna with long bodies and many legs like millipedes (Diplopoda) and centipedes (Chilopoda)[11]. While millipedes (Figure 7) are detritivores, centipedes are carnivorous with pincer-like fangs that feed mostly on other small organisms like collembolans.

='''References'''=
[1] Coleman, David C., et al. Fundamentals of Soil Ecology. Elsevier Academic Press, 2004.

[2] Burns, Keanna. “Otherworldly Amoebas.” Future Science Leaders, 31 July 2014, www.futurescienceleaders.com/mariecurious/2014/02/03/otherworldly-amoebas/.

[3] Smith, Humphrey Graham, et al. “Diversity and Biogeography of Testate Amoebae.” Protist Diversity and Geographical Distribution Topics in Biodiversity and Conservation, 2007, pp. 95–109., doi:10.1007/978-90-481-2801-3_8.

[4] Lynn, Denis H. “Ciliophora.” Encyclopedia of Life Sciences, 16 Apr. 2012, doi:10.1002/9780470015902.a0001966.pub3.

[5] Wallace, Robert Lee, and Hillary April Smith. “Rotifera.” Encyclopedia of Life Sciences, vol. 1, 15 May 2013, doi:10.1038/npg.els.0001588.

[6] Howey, Richard L. “The Wonderfully Weird World of Rotifers.” Micscape Microscopy and Microscope Magazine, 1999, www.microscopy-uk.org.uk/mag/indexmag.html?http%3A%2F%2Fwww.microscopy-uk.org.uk%2Fmag%2Fartnov99%2Frotih.html.

[7] Poinar, George. “Nematoda (Roundworms).” Encyclopedia of Life Sciences, 15 May 2012, doi:10.1002/9780470015902.a0001593.pub3.

[8] Strong, D. R., et al. “Entomopathogenic Nematodes: Natural Enemies of Root-Feeding Caterpillars on Bush Lupine.” Oecologia, vol. 108, no. 1, 1996, pp. 167–173., doi:10.1007/bf00333228.

[9] “Marine Nematodes Get New Digs!” National Museum of Natural History Unearthed, 21 Sept. 2015, nmnh.typepad.com/no_bones/2015/09/marine-nematodes-get-new-digs.html.

[10] Miller, W. R. (2011). Tardigrades. American Scientist, 99(5), 384–391. https://doi.org/10.1511/2011.92.384

[11] Wright, Jonathan C. “Myriapoda (Including Centipedes and Millipedes).” Encyclopedia of Life Sciences, Oct. 2012, www.els.net/WileyCDA/ElsArticle/refId-a0001607.html.

[12] Struck, Torsten H, et al. “Annelid Phylogeny and the Status of Sipuncula and Echiura.” BMC Evolutionary Biology, vol. 7, no. 1, 2007, p. 57., doi:10.1186/1471-2148-7-57.

File:Isopods.png

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File:Millipedes.png

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File:Centipedes.png

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File:Nematoda.png

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File:Rotifera.png

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File:Naked amoeba.jpg

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Amyschme:

Properties

2018-05-07T20:52:51Z

Amyschme: /* Soil Texture */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[Soil Horizons|soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since [[clay|clays]] have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences [[Water Behavior in Soils|water percolation]] and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[Soil Structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:52:24Z

Amyschme: /* Soil Texture */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[Soil Horizons|soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since [[clay|clays]] have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences [[Water Behavior in Soil|water percolation]] and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[Soil Structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:51:39Z

Amyschme: /* Structure */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[Soil Horizons|soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since [[clay|clays]] have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, [[Sand|sandy soils]] drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[Soil Structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:50:00Z

Amyschme: /* Soil Texture */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[Soil Horizons|soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since [[clay|clays]] have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, [[Sand|sandy soils]] drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[soil structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:49:45Z

Amyschme: /* Soil Properties */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[Soil Horizons|soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since [[clay|clays]] have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, [[sand|sandy soils]] drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[soil structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:47:58Z

Amyschme: /* Soil Texture */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since [[clay|clays]] have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, [[sand|sandy soils]] drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[soil structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:45:27Z

Amyschme: /* Structure */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The [[soil structures|structure]] of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:43:53Z

Amyschme: /* Soil Properties */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by [[soil horizons]], as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:43:17Z

Amyschme: /* Structure */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by soil horizons, as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form [[aggregate formation|aggregates]], and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Properties

2018-05-07T20:42:28Z

Amyschme: /* Soil Texture */

== '''Soil Properties''' ==

Soil properties vary from location to location due to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by soil horizons, as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its [[Soil Textures|texture]], or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form aggregates, and the size and stability of these aggregates depend on factors such as mineral composition, texture, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prism-like, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinner plates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yields plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

Aggregate formation

2018-04-20T01:02:24Z

Amyschme: /* Macroaggregates */

== '''Soil Aggregates''' ==

Soil aggregates are pieces or chunks of soil that bind together more tightly to one another due to a variety of factors. Certain soil particles bind together due to the activity of earthworms, fungal hyphae root exudes, and bacterial and fungal debris [1].[[File:aggregates.png|300px|thumb|left|Figure 1 [9] - soil aggregates attached to plant roots.]] The size of soil aggregates can vary across five degrees of magnitude [1], and the size of these aggregates affect porosity, water retention, soil organic material content, erosion, and available resources for microorganisms living in the soil [2].

[[File:aggregate-sizes.png|250px|thumb|right|Figure 2 - adapted from Fig. 1.9 [1] - soil aggregate sizing.]]

== Microaggregates ==

Microaggregates (< 250 um) are predominantly made from silt and clay and are held together by chemical charges (in the case of clay [3]) bacterial byproducts, and root exudes [4]. Earthworms have a large part in producing microaggregates through digestion of soil. They also unknowingly prepare these microaggregates to bind together via mucus from their gut to form macro aggregates [8]. Soil organic matter (vegetation), climate, composition, and management practices are responsible for forming macroaggregates [5].

== Macroaggregates ==

When plant roots penetrate the soil, they anchor chunks of soil together and help form macroaggregates. Macroaggregates (> 250 um) are typically formed in soils with high volumes of soil organic matter (SOM). [[File:Rootz.png|150px|thumb|left|Figure 3 [11] - Plant roots contribute to macroaggregate formation. ]] The breakdown of different types of detritus leads to a high diversity in the stages of SOM decomposition, which impacts the way aggregates form.[[File:USDA_aggregates.png|180px|thumb|right|Figure 4 [10] - the United States Department of Agriculture measures soil aggregate strength by placing aggregates in water held by metal mesh to determine how it will hold up in heavy rainfall. The soil aggregates to the left are more stable than the ones on the right. ]] Waxy organic material like pine needles, or OM that is high in lignin like oak leaves decompose slowly because of the complexity of their composition. In general, waxy detritus takes more time to form stable macroaggregates in comparison to litter that contains predominantly simpler compounds. The higher the level of organic matter decomposition, the larger and more stable the aggregates [4], and the more fertile the soil is. In general, soils with high SOM yield larger aggregates, which are more stable and less susceptible to erosion than smaller aggregates [6].

== Soil Moisture and Aggregate Stability ==

Environments with longer periods of time between drying and wetting tend to yield finer soil aggregates [7]. These soils are usually not as consistently productive as those found in locations with regular rainfall.
While the surface area of microaggregates is extensive, they are also more unstable than macroaggregates, and both are needed to maintain a healthy and productive soil. Microaggregates in topsoil are more prone to runoff in heavy rainfalls, while macroaggregates maintain soil stability [6]. Stable soils make for good agricultural yields because they do not crumble under rainfall, and instead retain water so that it is more available for root uptake [4]. The USDA measures soil stability by suspending aggregates in water for a certain length of time and observing if the aggregates maintain their structure or crumble after being submerged as shown in Figure 4 [10]. If they maintain their shape, it indicates a high level of soil organic matter and nutrient content and subsequent higher level of stability in agriculture [4]. Less stable (crumbly) soils are prone to erosion from wind and rainfall and do not usually maintain high levels of plant diversity.

==References==
[1] Coleman, David C., et al. ''Fundamentals of Soil Ecology''. Elsevier Academic Press, 2004.

[2] Spohn, Marie, and Luise Giani. “Impacts of Land Use Change on Soil Aggregation and Aggregate Stabilizing Compounds as Dependent on Time.” Soil Biology and Biochemistry, vol. 43, no. 5, 2011, pp. 1081–1088., doi:10.1016/j.soilbio.2011.01.029.

[3] Regelink, Inge C., et al. “Linkages between Aggregate Formation, Porosity and Soil Chemical Properties.” Geoderma, vol. 247-248, 2015, pp. 24–37., doi:10.1016/j.geoderma.2015.01.022.

[4] United States Department of Agriculture, and National Resource Conservation Service. “Soil Quality Indicators: Aggregate Stability.” Apr. 1996.

[5] Jastrow, J.d. “Soil Aggregate Formation and the Accrual of Particulate and Mineral-Associated Organic Matter.” Soil Biology and Biochemistry, vol. 28, no. 4-5, 1996, pp. 665–676., doi:10.1016/0038-0717(95)00159-x.

[6] Bensard, E., et al. “Fate of Particulate Organic Matter in Soil Aggregates during Cultivation.” European Journal of Soil Science, Wiley/Blackwell (10.1111), 10 Aug. 2005, onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.1996.tb01849.x/abstract.

[7] Semmel, H., et al. “The Dynamics of Soil Aggregate Formation and the Effect on Soil Physical Properties.” Soil Technology, vol. 3, no. 2, 1990, pp. 113–129., doi:10.1016/s0933-3630(05)80002-9.

[8] Six, Johan, and Keith Paustian. “Aggregate-Associated Soil Organic Matter as an Ecosystem Property and a Measurement Tool.” Soil Biology and Biochemistry, vol. 68, 2014, doi:10.1016/j.soilbio.2013.06.014.

[9] Jordan, Antonio. “Soil Aggregation - What Is Soil Structure?” Soil System Sciences, The European Geosciences Union, 19 Aug. 2013, blogs.egu.eu/divisions/sss/tag/soil-aggregation/.

[10]“Soil Organic Matter (Aggregate Stability).” USDA / NRCS, Natural Resources Conservation Service, www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054302.

[11] “Dave Leonard Tree Specialists.” Lexington Tree Service by Dave Leonard Tree Specialists - Emerald Ash Borer Treatment Experts, www.dlarborist.com/lawn-care.php.

Aggregate formation

2018-04-20T01:02:12Z

Amyschme: /* Microaggregates */

== '''Soil Aggregates''' ==

Soil aggregates are pieces or chunks of soil that bind together more tightly to one another due to a variety of factors. Certain soil particles bind together due to the activity of earthworms, fungal hyphae root exudes, and bacterial and fungal debris [1].[[File:aggregates.png|300px|thumb|left|Figure 1 [9] - soil aggregates attached to plant roots.]] The size of soil aggregates can vary across five degrees of magnitude [1], and the size of these aggregates affect porosity, water retention, soil organic material content, erosion, and available resources for microorganisms living in the soil [2].

[[File:aggregate-sizes.png|250px|thumb|right|Figure 2 - adapted from Fig. 1.9 [1] - soil aggregate sizing.]]

== Microaggregates ==

Microaggregates (< 250 um) are predominantly made from silt and clay and are held together by chemical charges (in the case of clay [3]) bacterial byproducts, and root exudes [4]. Earthworms have a large part in producing microaggregates through digestion of soil. They also unknowingly prepare these microaggregates to bind together via mucus from their gut to form macro aggregates [8]. Soil organic matter (vegetation), climate, composition, and management practices are responsible for forming macroaggregates [5].

== Macroaggregates ==

When plant roots penetrate the soil, they anchor chunks of soil together and help form macroaggregates. Macroaggregates (>250 um) are typically formed in soils with high volumes of soil organic matter (SOM). [[File:Rootz.png|150px|thumb|left|Figure 3 [11] - Plant roots contribute to macroaggregate formation. ]] The breakdown of different types of detritus leads to a high diversity in the stages of SOM decomposition, which impacts the way aggregates form.[[File:USDA_aggregates.png|180px|thumb|right|Figure 4 [10] - the United States Department of Agriculture measures soil aggregate strength by placing aggregates in water held by metal mesh to determine how it will hold up in heavy rainfall. The soil aggregates to the left are more stable than the ones on the right. ]] Waxy organic material like pine needles, or OM that is high in lignin like oak leaves decompose slowly because of the complexity of their composition. In general, waxy detritus takes more time to form stable macroaggregates in comparison to litter that contains predominantly simpler compounds. The higher the level of organic matter decomposition, the larger and more stable the aggregates [4], and the more fertile the soil is. In general, soils with high SOM yield larger aggregates, which are more stable and less susceptible to erosion than smaller aggregates [6].

== Soil Moisture and Aggregate Stability ==

Environments with longer periods of time between drying and wetting tend to yield finer soil aggregates [7]. These soils are usually not as consistently productive as those found in locations with regular rainfall.
While the surface area of microaggregates is extensive, they are also more unstable than macroaggregates, and both are needed to maintain a healthy and productive soil. Microaggregates in topsoil are more prone to runoff in heavy rainfalls, while macroaggregates maintain soil stability [6]. Stable soils make for good agricultural yields because they do not crumble under rainfall, and instead retain water so that it is more available for root uptake [4]. The USDA measures soil stability by suspending aggregates in water for a certain length of time and observing if the aggregates maintain their structure or crumble after being submerged as shown in Figure 4 [10]. If they maintain their shape, it indicates a high level of soil organic matter and nutrient content and subsequent higher level of stability in agriculture [4]. Less stable (crumbly) soils are prone to erosion from wind and rainfall and do not usually maintain high levels of plant diversity.

==References==
[1] Coleman, David C., et al. ''Fundamentals of Soil Ecology''. Elsevier Academic Press, 2004.

[2] Spohn, Marie, and Luise Giani. “Impacts of Land Use Change on Soil Aggregation and Aggregate Stabilizing Compounds as Dependent on Time.” Soil Biology and Biochemistry, vol. 43, no. 5, 2011, pp. 1081–1088., doi:10.1016/j.soilbio.2011.01.029.

[3] Regelink, Inge C., et al. “Linkages between Aggregate Formation, Porosity and Soil Chemical Properties.” Geoderma, vol. 247-248, 2015, pp. 24–37., doi:10.1016/j.geoderma.2015.01.022.

[4] United States Department of Agriculture, and National Resource Conservation Service. “Soil Quality Indicators: Aggregate Stability.” Apr. 1996.

[5] Jastrow, J.d. “Soil Aggregate Formation and the Accrual of Particulate and Mineral-Associated Organic Matter.” Soil Biology and Biochemistry, vol. 28, no. 4-5, 1996, pp. 665–676., doi:10.1016/0038-0717(95)00159-x.

[6] Bensard, E., et al. “Fate of Particulate Organic Matter in Soil Aggregates during Cultivation.” European Journal of Soil Science, Wiley/Blackwell (10.1111), 10 Aug. 2005, onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.1996.tb01849.x/abstract.

[7] Semmel, H., et al. “The Dynamics of Soil Aggregate Formation and the Effect on Soil Physical Properties.” Soil Technology, vol. 3, no. 2, 1990, pp. 113–129., doi:10.1016/s0933-3630(05)80002-9.

[8] Six, Johan, and Keith Paustian. “Aggregate-Associated Soil Organic Matter as an Ecosystem Property and a Measurement Tool.” Soil Biology and Biochemistry, vol. 68, 2014, doi:10.1016/j.soilbio.2013.06.014.

[9] Jordan, Antonio. “Soil Aggregation - What Is Soil Structure?” Soil System Sciences, The European Geosciences Union, 19 Aug. 2013, blogs.egu.eu/divisions/sss/tag/soil-aggregation/.

[10]“Soil Organic Matter (Aggregate Stability).” USDA / NRCS, Natural Resources Conservation Service, www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054302.

[11] “Dave Leonard Tree Specialists.” Lexington Tree Service by Dave Leonard Tree Specialists - Emerald Ash Borer Treatment Experts, www.dlarborist.com/lawn-care.php.

Aggregate formation

2018-04-20T01:01:06Z

Amyschme:

== '''Soil Aggregates''' ==

Soil aggregates are pieces or chunks of soil that bind together more tightly to one another due to a variety of factors. Certain soil particles bind together due to the activity of earthworms, fungal hyphae root exudes, and bacterial and fungal debris [1].[[File:aggregates.png|300px|thumb|left|Figure 1 [9] - soil aggregates attached to plant roots.]] The size of soil aggregates can vary across five degrees of magnitude [1], and the size of these aggregates affect porosity, water retention, soil organic material content, erosion, and available resources for microorganisms living in the soil [2].

[[File:aggregate-sizes.png|250px|thumb|right|Figure 2 - adapted from Fig. 1.9 [1] - soil aggregate sizing.]]

== Microaggregates ==

Microaggregates (<250 um) are predominantly made from silt and clay and are held together by chemical charges (in the case of clay [3]) bacterial byproducts, and root exudes [4]. Earthworms have a large part in producing microaggregates through digestion of soil. They also unknowingly prepare these microaggregates to bind together via mucus from their gut to form macro aggregates [8]. Soil organic matter (vegetation), climate, composition, and management practices are responsible for forming macroaggregates [5].

== Macroaggregates ==

When plant roots penetrate the soil, they anchor chunks of soil together and help form macroaggregates. Macroaggregates (>250 um) are typically formed in soils with high volumes of soil organic matter (SOM). [[File:Rootz.png|150px|thumb|left|Figure 3 [11] - Plant roots contribute to macroaggregate formation. ]] The breakdown of different types of detritus leads to a high diversity in the stages of SOM decomposition, which impacts the way aggregates form.[[File:USDA_aggregates.png|180px|thumb|right|Figure 4 [10] - the United States Department of Agriculture measures soil aggregate strength by placing aggregates in water held by metal mesh to determine how it will hold up in heavy rainfall. The soil aggregates to the left are more stable than the ones on the right. ]] Waxy organic material like pine needles, or OM that is high in lignin like oak leaves decompose slowly because of the complexity of their composition. In general, waxy detritus takes more time to form stable macroaggregates in comparison to litter that contains predominantly simpler compounds. The higher the level of organic matter decomposition, the larger and more stable the aggregates [4], and the more fertile the soil is. In general, soils with high SOM yield larger aggregates, which are more stable and less susceptible to erosion than smaller aggregates [6].

== Soil Moisture and Aggregate Stability ==

Environments with longer periods of time between drying and wetting tend to yield finer soil aggregates [7]. These soils are usually not as consistently productive as those found in locations with regular rainfall.
While the surface area of microaggregates is extensive, they are also more unstable than macroaggregates, and both are needed to maintain a healthy and productive soil. Microaggregates in topsoil are more prone to runoff in heavy rainfalls, while macroaggregates maintain soil stability [6]. Stable soils make for good agricultural yields because they do not crumble under rainfall, and instead retain water so that it is more available for root uptake [4]. The USDA measures soil stability by suspending aggregates in water for a certain length of time and observing if the aggregates maintain their structure or crumble after being submerged as shown in Figure 4 [10]. If they maintain their shape, it indicates a high level of soil organic matter and nutrient content and subsequent higher level of stability in agriculture [4]. Less stable (crumbly) soils are prone to erosion from wind and rainfall and do not usually maintain high levels of plant diversity.

==References==
[1] Coleman, David C., et al. ''Fundamentals of Soil Ecology''. Elsevier Academic Press, 2004.

[2] Spohn, Marie, and Luise Giani. “Impacts of Land Use Change on Soil Aggregation and Aggregate Stabilizing Compounds as Dependent on Time.” Soil Biology and Biochemistry, vol. 43, no. 5, 2011, pp. 1081–1088., doi:10.1016/j.soilbio.2011.01.029.

[3] Regelink, Inge C., et al. “Linkages between Aggregate Formation, Porosity and Soil Chemical Properties.” Geoderma, vol. 247-248, 2015, pp. 24–37., doi:10.1016/j.geoderma.2015.01.022.

[4] United States Department of Agriculture, and National Resource Conservation Service. “Soil Quality Indicators: Aggregate Stability.” Apr. 1996.

[5] Jastrow, J.d. “Soil Aggregate Formation and the Accrual of Particulate and Mineral-Associated Organic Matter.” Soil Biology and Biochemistry, vol. 28, no. 4-5, 1996, pp. 665–676., doi:10.1016/0038-0717(95)00159-x.

[6] Bensard, E., et al. “Fate of Particulate Organic Matter in Soil Aggregates during Cultivation.” European Journal of Soil Science, Wiley/Blackwell (10.1111), 10 Aug. 2005, onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.1996.tb01849.x/abstract.

[7] Semmel, H., et al. “The Dynamics of Soil Aggregate Formation and the Effect on Soil Physical Properties.” Soil Technology, vol. 3, no. 2, 1990, pp. 113–129., doi:10.1016/s0933-3630(05)80002-9.

[8] Six, Johan, and Keith Paustian. “Aggregate-Associated Soil Organic Matter as an Ecosystem Property and a Measurement Tool.” Soil Biology and Biochemistry, vol. 68, 2014, doi:10.1016/j.soilbio.2013.06.014.

[9] Jordan, Antonio. “Soil Aggregation - What Is Soil Structure?” Soil System Sciences, The European Geosciences Union, 19 Aug. 2013, blogs.egu.eu/divisions/sss/tag/soil-aggregation/.

[10]“Soil Organic Matter (Aggregate Stability).” USDA / NRCS, Natural Resources Conservation Service, www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054302.

[11] “Dave Leonard Tree Specialists.” Lexington Tree Service by Dave Leonard Tree Specialists - Emerald Ash Borer Treatment Experts, www.dlarborist.com/lawn-care.php.

Aggregate formation

2018-04-20T01:00:23Z

Amyschme: Created page with "== '''Soil Aggregates''' == Soil aggregates are pieces or chunks of soil that bind together more tightly to one another due to a variety of factors. Certain soil particles..."

== '''Soil Aggregates''' ==

Soil aggregates are pieces or chunks of soil that bind together more tightly to one another due to a variety of factors. Certain soil particles bind together due to the activity of earthworms, fungal hyphae root exudes, and bacterial and fungal debris [1].[[File:aggregates.png|300px|thumb|left|Figure 1 [9] - soil aggregates attached to plant roots.]] The size of soil aggregates can vary across five degrees of magnitude [1], and the size of these aggregates affect porosity, water retention, soil organic material content, erosion, and available resources for microorganisms living in the soil [2].

[[File:aggregate-sizes.png|250px|thumb|right|Figure 2 - adapted from Fig. 1.9 [1] - soil aggregate sizing.]]

== Microaggregates ==

Microaggregates (<250 um) are predominantly made from silt and clay and are held together by chemical charges (in the case of clay [3]) bacterial byproducts, and root exudes [4]. Earthworms have a large part in producing microaggregates through digestion of soil. They also unknowingly prepare these microaggregates to bind together via mucus from their gut to form macro aggregates [8]. Soil organic matter (vegetation), climate, composition, and management practices are responsible for forming macroaggregates [5].

== Macroaggregates ==

When plant roots penetrate the soil, they anchor chunks of soil together and help form macroaggregates. Macroaggregates (>250 um) are typically formed in soils with high volumes of soil organic matter (SOM). [[File:Rootz.png|150px|thumb|left|Figure 3 [11] - Plant roots contribute to macroaggregate formation. ]] The breakdown of different types of detritus leads to a high diversity in the stages of SOM decomposition, which impacts the way aggregates form.[[File:USDA_aggregates.png|180px|thumb|right|Figure 4 [10] - the United States Department of Agriculture measures soil aggregate strength by placing aggregates in water held by metal mesh to determine how it will hold up in heavy rainfall. The soil aggregates to the left are more stable than the ones on the right. ]] Waxy organic material like pine needles, or OM that is high in lignin like oak leaves decompose slowly because of the complexity of their composition. In general, waxy detritus takes more time to form stable macroaggregates in comparison to litter that contains predominantly simpler compounds. The higher the level of organic matter decomposition, the larger and more stable the aggregates [4], and the more fertile the soil is. In general, soils with high SOM yield larger aggregates, which are more stable and less susceptible to erosion than smaller aggregates [6].

== Soil Moisture and Aggregate Stability ==

Environments with longer periods of time between drying and wetting tend to yield finer soil aggregates [7]. These soils are usually not as consistently productive as those found in locations with regular rainfall.
While the surface area of microaggregates is extensive, they are also more unstable than macroaggregates, and both are needed to maintain a healthy and productive soil. Microaggregates in topsoil are more prone to runoff in heavy rainfalls, while macroaggregates maintain soil stability [6]. Stable soils make for good agricultural yields because they do not crumble under rainfall, and instead retain water so that it is more available for root uptake [4]. The USDA measures soil stability by suspending aggregates in water for a certain length of time and observing if the aggregates maintain their structure or crumble after being submerged as shown in Figure 4 [10]. If they maintain their shape, it indicates a high level of soil organic matter and nutrient content and subsequent higher level of stability in agriculture [4]. Less stable (crumbly) soils are prone to erosion from wind and rainfall and do not usually maintain high levels of plant diversity.

==References==
[1] Coleman, David C., et al. ''Fundamentals of Soil Ecology''. Elsevier Academic Press, 2004.

[2] Spohn, Marie, and Luise Giani. “Impacts of Land Use Change on Soil Aggregation and Aggregate Stabilizing Compounds as Dependent on Time.” Soil Biology and Biochemistry, vol. 43, no. 5, 2011, pp. 1081–1088., doi:10.1016/j.soilbio.2011.01.029.

[3] Regelink, Inge C., et al. “Linkages between Aggregate Formation, Porosity and Soil Chemical Properties.” Geoderma, vol. 247-248, 2015, pp. 24–37., doi:10.1016/j.geoderma.2015.01.022.

[4] United States Department of Agriculture, and National Resource Conservation Service. “Soil Quality Indicators: Aggregate Stability.” Apr. 1996.

[5] Jastrow, J.d. “Soil Aggregate Formation and the Accrual of Particulate and Mineral-Associated Organic Matter.” Soil Biology and Biochemistry, vol. 28, no. 4-5, 1996, pp. 665–676., doi:10.1016/0038-0717(95)00159-x.

[6] Bensard, E., et al. “Fate of Particulate Organic Matter in Soil Aggregates during Cultivation.” European Journal of Soil Science, Wiley/Blackwell (10.1111), 10 Aug. 2005, onlinelibrary.wiley.com/doi/10.1111/j.1365-2389.1996.tb01849.x/abstract.

[7] Semmel, H., et al. “The Dynamics of Soil Aggregate Formation and the Effect on Soil Physical Properties.” Soil Technology, vol. 3, no. 2, 1990, pp. 113–129., doi:10.1016/s0933-3630(05)80002-9.

[8] Six, Johan, and Keith Paustian. “Aggregate-Associated Soil Organic Matter as an Ecosystem Property and a Measurement Tool.” Soil Biology and Biochemistry, vol. 68, 2014, doi:10.1016/j.soilbio.2013.06.014.

[9] Jordan, Antonio. “Soil Aggregation - What Is Soil Structure?” Soil System Sciences, The European Geosciences Union, 19 Aug. 2013, blogs.egu.eu/divisions/sss/tag/soil-aggregation/.

[10]“Soil Organic Matter (Aggregate Stability).” USDA / NRCS, Natural Resources Conservation Service, www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054302.

[11] “Dave Leonard Tree Specialists.” Lexington Tree Service by Dave Leonard Tree Specialists - Emerald Ash Borer Treatment Experts, www.dlarborist.com/lawn-care.php.

File:Rootz.png

2018-04-20T00:38:16Z

Amyschme: Amyschme uploaded a new version of File:Rootz.png

File:Rootz.png

2018-04-20T00:32:01Z

Amyschme:

File:USDA aggregates.png

2018-04-20T00:14:56Z

Amyschme:

File:Aggregate-sizes.png

2018-04-19T23:55:06Z

Amyschme:

File:Aggregates.png

2018-04-19T23:50:48Z

Amyschme:

Main Page

2018-03-14T16:51:24Z

Amyschme:

=[[Soil Ecology]] WIKI from the University at Buffalo=
[[File:Rhizo.jpg|230px|thumb|left|Soil ecology encompasses interactions between plants, soils, and the organisms that live within them.]] [[Soil]] is a vast reservoir for a wide [[diversity]] of [[organisms]]. [[Plant roots]] explore this [[diversity]] daily. Various other [[animals]] consume [[smaller creatures]] either intentionally or unintentionally by [[foraging]] on [[plant roots]], [[insects]], and [[microorganisms]].
Soil ecology is the study of how these [[soil organisms]] interact with other organisms and their environment - their influence on and response to numerous [[soil processes]] and [[properties]] form the basis for delivering [[essential ecosystem services]]. Some of the key processes in soil are [[nutrient cycling]], soil [[aggregate formation]], and [[biodiversity interactions]]. Sometimes, individual species can strongly influence overall soil ecology, such as [[Black Willow]]
The [[diversity]] and abundance of [[soil life]] exceeds that of any other ecosystem. [[Plant establishment]], competitiveness, and growth is governed largely by the [[ecology belowground]], with many interactions attributed to the interconnectivity of [[Plant Roots]] due to [[Arbuscular Mycorrhizal Fungi]] and [[Ectomycorrhizal Fungi]]. Therefore, a deep understanding of these systems are an essential component of plant sciences and [[terrestrial ecology]].

Many of the concepts of soil ecology were developed by Hans Jenny and his creation of the [[Jenny Equation]]. These concepts envelop the ideas of the abiotic interactions of [[Organisms]] and plants.

=List of Possible Topics:=

[[Ecosystem Services]], [[Vegetable Mould]], [[Founders of Soil Concepts]], [[Pedogenesis]], [[Jenny Equation]], [[Water Behavior in Soils]], [[Soil Horizons]], [[Soil Textures]], [[Monocots]], [[Dicots]], [[Arbuscular Mycorrhizal Fungi]], [[Rhizodeposition]], [[Soil Sampling Methods]], [[Zygomycota]], [[Glomeromycota]], [[Ascomycota]], [[Basidiomycota]], [[Humus]], [[Clay]], [[Silt]], [[Loam]], [[Soil Structures]], [[Flavonoids]] , [[Diazotrophs]], [[Black Willow]], [[Cryprogamic Soil Crust]], [[Ciliates]], [[Nutrient Cycling]], [[Isopods]], [[Nematodes]]

If you dudes/dudettes have any questions, email me at krzidell and I'll do everything I can.

Main Page

2018-03-14T16:50:50Z

Amyschme:

=[[Soil Ecology]] WIKI from the University at Buffalo=
[[File:Rhizo.jpg|230px|thumb|left|Soil ecology encompasses interactions between plants, soils, and the organisms that live within them.]] [[Soil]] is a vast reservoir for a wide [[diversity]] of [[organisms]]. [[Plant roots]] explore this [[diversity]] daily. Various other [[animals]] consume [[smaller creatures]] either intentionally or unintentionally by [[foraging]] on [[plant roots]], [[insects]], and [[microorganisms]].
Soil ecology is the study of how these [[soil organisms]] interact with other organisms and their environment - their influence on and response to numerous [[soil processes]] and [[soil properties]] form the basis for delivering [[essential ecosystem services]]. Some of the key processes in soil are [[nutrient cycling]], soil [[aggregate formation]], and [[biodiversity interactions]]. Sometimes, individual species can strongly influence overall soil ecology, such as [[Black Willow]]
The [[diversity]] and abundance of [[soil life]] exceeds that of any other ecosystem. [[Plant establishment]], competitiveness, and growth is governed largely by the [[ecology belowground]], with many interactions attributed to the interconnectivity of [[Plant Roots]] due to [[Arbuscular Mycorrhizal Fungi]] and [[Ectomycorrhizal Fungi]]. Therefore, a deep understanding of these systems are an essential component of plant sciences and [[terrestrial ecology]].

Many of the concepts of soil ecology were developed by Hans Jenny and his creation of the [[Jenny Equation]]. These concepts envelop the ideas of the abiotic interactions of [[Organisms]] and plants.

=List of Possible Topics:=

[[Ecosystem Services]], [[Vegetable Mould]], [[Founders of Soil Concepts]], [[Pedogenesis]], [[Jenny Equation]], [[Water Behavior in Soils]], [[Soil Horizons]], [[Soil Textures]], [[Monocots]], [[Dicots]], [[Arbuscular Mycorrhizal Fungi]], [[Rhizodeposition]], [[Soil Sampling Methods]], [[Zygomycota]], [[Glomeromycota]], [[Ascomycota]], [[Basidiomycota]], [[Humus]], [[Clay]], [[Silt]], [[Loam]], [[Soil Structures]], [[Flavonoids]] , [[Diazotrophs]], [[Black Willow]], [[Cryprogamic Soil Crust]], [[Ciliates]], [[Nutrient Cycling]], [[Isopods]], [[Nematodes]]

If you dudes/dudettes have any questions, email me at krzidell and I'll do everything I can.

Properties

2018-03-06T23:18:24Z

Amyschme:

== '''Soil Properties''' ==

Soil properties vary from location to location do to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by soil horizons, as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its texture, or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form aggregates, and the size and stability of these aggregates depend on factors such as mineral composition, texure, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prismlike, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinnerplates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yield plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

===Soil pH===
[[File:Soil pH.png|300px|thumb|left| Nutrient availability relative to pH [17]]]
A solution's pH is a measurement of how many hydrogen ions are present on a logarithmic scale of 1-14, where 7.0 is neutral, anything less than 7.0 is acidic, and anything over 7.0 is basic (alkaline). The availability of micronutrients and nitrogen, phosphorous, and potassium are affected by soil pH levels. For example, micronutrients such as manganese, iron, copper, and zinc tend to decrease in availability as soil pH increases [14]. Nitrification is also slow in acidic soils.

As previously stated, adding lime to soil increases soil pH and neutralizes acidic soils, making them more suitable for agriculture [13]. According to the US Department of Agriculture, benefits of liming acidic soils include improvement of microbial activity, soil structure, nitrogen fixation in legumes, and some nutrient availability, and reduces the possibility of Mn2+ and Al3+ toxicity. Liming also increases potassium availability [14]. However, liming soils is not always necessary, as different crops have varying tolerances and preferences to acidity in soils [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid Soils." Natural Resources Conservation Service, United States Department of Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003, www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017, www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

[17] Soil Analysis: Key to Nutrient Management Planning.” Potash Development Association (PDA), www.pda.org.uk/pda_leaflets/24-soil-analysis-key-to-nutrient-management-planning/.

File:Soil pH.png

2018-03-06T23:12:40Z

Amyschme: soil pH and nutrient availability

soil pH and nutrient availability

Properties

2018-03-06T23:01:01Z

Amyschme:

== '''Soil Properties''' ==

Soil properties vary from location to location do to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by soil horizons, as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its texture, or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form aggregates, and the size and stability of these aggregates depend on factors such as mineral composition, texure, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prismlike, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinnerplates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yield plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid
Soils." Natural Resources Conservation Service, United States Department of
Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division,
Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH
and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003,
www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017,
www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

Properties

2018-03-06T23:00:31Z

Amyschme:

== '''Soil Properties''' ==

Soil properties vary from location to location do to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by soil horizons, as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

=== Soil Texture ===
Soil is usually named by its texture, or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

=== Structure ===
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form aggregates, and the size and stability of these aggregates depend on factors such as mineral composition, texure, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prismlike, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinnerplates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yield plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

=== Color ===
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid
Soils." Natural Resources Conservation Service, United States Department of
Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division,
Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH
and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003,
www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017,
www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

Properties

2018-03-06T22:59:34Z

Amyschme: Soil properties vary from location to location do to the massively heterogeneous nature of soil. Understanding a soil's texture, color, structure, and chemistry is helpful in predicting the life it can or cannot support.

== '''Soil Properties''' ==

Soil properties vary from location to location do to the massively heterogeneous nature of soil. A soil's composition is a function of climate, organisms, relief, parent material, and time [1]. Soil properties vary largely by soil horizons, as shown in Figure 1; in general, the O-A-B-C-R layering is common, although variations do exist.

[[File:Soil horizons.jpg|280px|thumb|left|Figure 1 [15] - soil horizons very in depth depending on the environment in which they are found, but in general all soils have these basic layers.]]

Soil horizons lay parallel to the earth's surface and one another. The O horizon contains organic material and relatively undecomposed litter. Following, the A layer is a dark layer, often referred to as topsoil and/or humus, which is where most biological activity occurs in the form of plants, bacteria, archaea, and numerous macroinvertebrates. Below this is the B layer, or subsoil, where many soil nutrients and illuvium (material leached from one soil horizon and deposited in another, usually via rainwater) accumulate. Next is the C layer, consisting of notably unweathered parent material of soils. The final layer is the bedrock, or the R layer, which is again, left unweathered due to its lack of exposure to many pedogenetic factors (like physical weathering from rainwater and the action of most macroinvertebrates) [2].

== Soil Texture ==
Soil is usually named by its texture, or its dominant grain size [3], which refers to the diameter of a singular grain of sediment. The soil triangle (Figure 2) is only useful once one has determined what the makeup of the soil is by percentage of each grain size. [[File:Wentworth Grain size.png|230px|thumb|right| Figure 3 - The terminology for grain size naming adapted from Wentworth by the USGS [16]. ]] Figure 3 illustrates the terminology for grain size from the USGS, from largest (boulders) to smallest (clay) [4]. Particle size is indirectly related to surface area. Since clays have the smallest particles, they have the most surface area and therefore retain large amounts of water [5]. On the contrary, sandy soils drain quickly and retain little water.
[[File:Soil Texture Triangle.png|300px|thumb|left|Figure 2 - The soil texture triangle comes from the NRCS, and it is used by determining the percentages of each grain size found in a soil sample. ]]

Soil texture influences water percolation and nutrient retention. Clay particles in heterogeneous soils are responsible for much of the nutrient retention [5]. Although clay retains more water than other soils, it does not readily provide this water to surrounding plant roots as others do. Clay is a major actor in a soil's ability to retain nutrients and make them readily available for root uptake due to its polarity and structure [6].

== Structure ==
The structure of the soil refers to the way in which the soil solids are organized in relation to one another. Soil particles clump together to form aggregates, and the size and stability of these aggregates depend on factors such as mineral composition, texure, moisture availability, and soil management factors [7]. Aggregates clump together, and the way in which they align themselves indicates soil structure.
There are four major types of soil structure: platelike, prismlike, blocklike, and spheroidal. Platelike structures are often found in compressed soils [8], can exist at any horizon, and have horizontal layers to them, like dinnerplates stacked on top of one another. Prismlike structures have vertical tube-like prisms that vary slightly and can be broken into prismatic (angular sides and tops) and columnar (rounded tops). Soil structures that are blocklike (blocky) can either be cubelike or subangular. These are common in humid regions. Spheroidal soils can either be granular or crumb, depending on their porosity (granular being porous while crumb being very porous) [6].
Soil structure influences water infiltration rates. Due to larger pore spaces, blocky and spheroidal soils have higher infiltration rates due to the large pore spaces between particles, while platy and prismatic have moderate-slow infiltration rates. Soil with larger aggregates yield plants with coarse roots, while finer soil aggregates yield finer roots. This influences uptake of certain nutrients but not others, as nitrates move quickly through water, but phosphorous intake is higher on finer rooted plants [9].

== Color ==
[[File:Munsell.png|200px|thumb|right| The Munsell color chart used to identify soil colors.]]
The most widely accepted color identification system is the Munsell color system [10], which is a book used in several mediums, from paint colors to soil science. The Munsell charts made specifically for soils focus predominantly on reds and yellows [11]. There are three parameters to soil color identification by the Munsell system. The hue indicates the general color of the sample, such as red, yellow, green, etc. A color's value is how light or dark it is. Lastly, the chroma is how weak or strong (vibrant) the color is [12].

The color of soil is indicative of what the soil is made up of, and what its mineral content is. For example, the soils at the A horizon is usually a dark brown, which is a result of the breakdown of organic matter and the oxidation of soil nutrients. Whiteish soils indicate a high concentration of calcium or magnesium carbonates and other soluble salts. Calcium carbonate (CaCO3), or more commonly known as limestone, indicates an alkaline soil, or one with a pH > 7.3, and is widely used to correct soil acidity in agriculture [13].

== References ==
[1] Amundson, Ronald, and Hans Jenny. "On a State Factor Model of Ecosystems." BioScience,
vol. 47, no. 8, 1997, pp. 536-543., doi:10.2307/1313122.

[2] "Appendix 1: Soil Horizon Designations." World Reference Base for Soil Resources, Food
and Agricultural Organization of the United Nations, 1998,
www.fao.org/docrep/W8594E/w8594e0g.htm.

[3] "Soil Texture Calculator." NRCS Soils, USDA Natural Resources Conservation Service,
www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/?cid=nrcs142p2_054167.

[4] Wentworth, Chester K. "A Scale of Grade and Class Terms for Clastic Sediments." The
Journal of Geology, vol. 30, no. 5, 1922, pp. 377-392., doi:10.1086/622910.

[5] Sheard, R.W. "Understanding Turf Management." Michigan State University Archives, 4
Sept. 1991, archive.lib.msu.edu/tic/stnew/article/1991sep4.pdf.

[6] "Fundamentals of Soil Ecology." Fundamentals of Soil Ecology, by D. C. Coleman, 2nd ed.,
Elsevier, 2004, pp. 1-21.

[7] Lal, R., editor. "Soil Structure and Organic Carbon: a Review." Soil Processes and the
Carbon Cycle, by B.D. Kay, CRC Press, 1998, pp. 169-197.

[8] Pagliai, M., et al. "Soil Structure and the Effect of Management Practices." Soil and Tillage
Research, vol. 79, no. 2, 2004, pp. 131-143., doi:10.1016/j.still.2004.07.002.

[9]Wiersum, L. K. "Uptake of Nitrogen and Phosphorus in Relation to Soil Structure and
Nutrient Mobility." Plant and Soil, vol. 16, no. 1, 1962, pp. 62-70.,
doi:10.1007/bf01378158.

[10] "The Color of Soil." The Color of Soil | NRCS Soils, United States Department of
Agriculture,
web.archive.org/web/20071027060221/http://soils.usda.gov/education/resources/k12/less
ons/color/.

[11] "Munsell Soil Color Charts." Munsell Color System; Color Matching from Munsell Color
Company, munsell.com/color-products/color-communications-products/environmental-
color-communication/munsell-soil-color-charts/.

[12] "How to Read a Munsell Color Chart." Munsell Color System; Color Matching from
Munsell Color Company, munsell.com/about-munsell-color/how-color-notation-works/how-to-read-color-chart/.

[13] "Soil Quality - Agronomy Technical Note No. 8: Liming to Improve Soil Quality in Acid
Soils." Natural Resources Conservation Service, United States Department of
Agriculture, www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_053252.pdf.

[14] Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division,
Crop Research and Extension Branch, Food and Bio-Industrial Crops Section. "Soil PH
and Plant Nutrients." Alberta Agriculture and Forestry, 15 May 2003,
www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6607.

[15] "Soil Geomorphology and Identification." Stevens Water, 16 Mar. 2017,
www.stevenswater.com/blog/post/?permalink=soil-geomorphology-and-identification.

[16] Wentworth grain size chart from United States Geological Survey Open-File Report 2006-
1195, "Surficial sediment character of the Louisiana offshore continental shelf region: A GIS Compilation" by Jeffress Williams, Matthew A. Arsenault, Brian J. Buczkowski, Jane A. Reid, James G. Flocks, Mark A. Kulp, Shea Penland, and Chris J. Jenkins

File:Munsell.png

2018-03-06T22:30:36Z

Amyschme: munsell soil color chart

munsell soil color chart

File:Wentworth Grain size.png

2018-03-06T20:35:22Z

Amyschme: Wentworth grain size chart

Wentworth grain size chart

File:Soil Texture Triangle.png

2018-03-06T20:26:49Z

Amyschme: soil texture triangle NRCS

soil texture triangle NRCS

File:Soil horizons.jpg

2018-03-06T20:13:31Z

Amyschme: Soil Horizons

Soil Horizons