Soil Ecology Wiki - User contributions [en]

Vernal Pools

2019-05-08T03:21:09Z

Jennapec:

[[File:Vernalseason.jpg|300px|right|thumb| [https://www.geocaching.com/geocache/GC6ZRQV_vernal-pool-earthcache?guid=451fa0e4-d882-4d81-936c-9e56bfb317ff] Vernal pool changes throughout seasons ]]

==Overview==
Vernal pools are defined as isolated, seasonal wetlands that are characterized by being relatively small, shallow, and ephemeral. These features are filled in the spring by rain and snow melt, and they dry up near the end of summer when evaporation rates and temperatures are at their highest. They last the longest against evaporation when the depressions are lined with thick [[Clay]], which slows the percolation rate of precipitation into the soil.[[#4.|[4]]] These pools form not only near other wetlands, but also in low lying areas with soil structures capable of holding water on top of the organic layer, or the [[Humus]] layer, of the [[Soil Horizons]].

These seasonal wetland bodies are vital ecosystems for various [[Organisms]] including but not limited to amphibians, [[Insects]], birds, and crustaceans. Vernal pools have been found on the tops of upland areas, woodlands, and urban areas. The key characteristic that contributes to the importance of these pools is that they are separated from other water bodies. When considering the characteristics of vernal pools, it is evident that vernal pools are unique and temporary wetland ecosystems. [[#13.|[13]]]

==Formation==

In order for vernal pools to form, many factors must align. The topography, water table (sometimes), soil history, and [[Soil processes]] all have to be just right before a vernal pool will take shape. Most vernal pools only occur in the Western Region and the Northeastern Region of the United States. They will form however in many parts of Canada, and many other Mediterranean or Subtropical regions on earth. [[#14.|[14]]]

Most believe that the water table in a region is the sole reason behind vernal pool formation, but this is not the case. Although the water table in an area can be extremely important in vernal pool formation. If the area has a higher water table, vernal pool formation will be promoted because water is more likely to pool up on the surface in the spring months and create vernal pools; This is common in wetland areas and near stream beds. However, the water table does not have to be high in order for a vernal pool to form. Vernal pools can form due to the rock below and holding runoff in an area, creating a suspended water table or a lower infiltration rate in that area. [[#14.|[14]]]

[[File:GlacialVernalPool.jpg|275px|left|thumb| [https://www.geocaching.com/geocache/GC6ZRQV_vernal-pool-earthcache?guid=451fa0e4-d882-4d81-936c-9e56bfb317ff.] Glacial vernal pool formation]]

The soil is often the promoting factor causing vernal pools to form. Areas that promote vernal pool formation are or were effected by ''glacial action'', ''floodplains'', ''sag ponds'', and even areas with ''human activity''. ''Floodplains'' are common areas for vernal pools because when there is high water or even a flood, water pockets will fill and remain full for a short period of time. This is most common in the spring during high periods of snow melt and rain. If there is a hard clay based layer in the soil, that will also assist in keeping the water pooled on top.

Areas that have been effected by ''glacial action'' often result in vernal pools. Glaciers create many depressions, scrapes, scours, and erosion in areas where they travel or melt away. The topography of the Northeastern United States and Canada is mostly shaped by the Laurentide Ice Sheet that covered the area from 11,700-2.6 MYA. These features left behind after glacier retreat are able to fill with precipitation resulting in ephemeral pools. A ''sag pond'' is created when there is an underlying rock susceptible to weathering. When the rock under the soil weathers, a depression will form in the soil above to fill the void of non-existent rock. This then creates an area for the water to pool, and to stay because of the remaining rock below the soil.

==Ecological Importance==
[[File:Vernalpoolwildflowers.jpg|250px|right|thumb| [https://www.tes.com/lessons/w4CKexdQnEoeAA/science] A community of wildflowers surrounding an ephemeral wetland]]

Vernal pools are the best habitat for many insects, amphibians, and plants; although their time frame before drying out may be short. The main advantage they have over other bodies of water is the lack of predatory aquatic species. Additionally, many birds will use larger vernal pools as seasonal water sources and migratory landing areas. Although much of the importance tied to vernal pools is due to the overwhelming amount of [[biodiversity interactions]] in the systems, including rare invertebrates, crustaceans, [[insects]], and plant species.

Various plant communities also play an important role in the vernal pool's sub-ecosystem. In the spring-time, wildflowers often bloom in circles on the shoreline of each pool and by time summer ends they're replaced with dry, cracked soil. [[#12.|[12]]] Plant species found in vernal pools are adapted to the high desiccation rate and stressful conditions present in the pools. These miniature wetlands thrive during and preceding the rainy season, with some staying dried for up to 6 months. [[#8.|[8]]] Some rare (and endangered) plant species that thrive in vernal pools are, '''Shumards Oak''', '''Raven's-foot sedge''', '''squarrose sedge''', and '''false hop sedge'''. [[#11.|[11]]] Some species that depend on vernal pools are, [[Tiger Salamander]], fairy Shrimp, and specifically female bees of the genus ''Andrena''. [[#6.|[6]]]

[[File:FrogEggs.jpg|275px|thumb|right| [https://www.fosc.org/VernalPool.htm]

Amphibian eggs covered in algae, found in a vernal pool of Sligo Creek Park]]

The hydrologic cycle of vernal pools is one of the key aspects making animal life in the pools so specific. This includes the time of inundation, size, depth change, evapotranspiration, and [[Water Behavior in Soils]]. Factors like water temperature, [[Soil]] chemistry, surrounding habitats, and [[Biodiversity interactions]] are what allows the wetlands to return annually. Many species that are found here will carry out their first few life stages and leave; others will stay put after the water evaporates. Fairy shrimp eggs can be laid as cysts for decades before they are exposed to a water source. These crustaceans will live typically for only a few months after they hatch because of natural reasons, including desiccation. [[#11.|[11]]]

==Declining Habitat==

Unfortunately, vernal pools have been in a state of decline since industrialization has become more frequent. Some of the earliest restoration efforts were made in 1980 by the Nature Conservancy, whose members started to buy areas in California containing the pools in order to preserve them.[[#2.|[2]]] Conservation efforts are difficult because of the ephemeral characteristic of the wetlands and the lack of education surrounding them.

Directly correlated to the rule of humans on planet earth, vernal pools are in a serious decline. This is a great problem for many species that are entirely dependent on vernal pools for survival. Wetlands are some of the most valuable ecosystems because of their biodiversity and [[ecosystem services]], vernal pools should not be excluded from this classification under wetlands. The biggest issue facing these sub ecosystems is development and destruction of forests, where most vernal pools can be located. Most real estate developers consider them to be obstacles in the development process; so regulation has been put into place in some areas that require fees to be paid in order to get a permit to build on these sites.[[#1.|[1]]] Vernal pools are abundant in forests in the Northeast and Western states, and when the forests are destroyed for human use, the vernal pools are ultimately succumbed as well. From 1800 to to 2018, forest coverage in Michigan alone has dropped from 89% to 45% and is continually approaching a lower percentage.[[#11.|[11]]]

Climate change has already shown affects on vernal pools in places like North Carolina[[#9.|[9]]], California[[#3.|[3]]] and others. With increasing temperatures and overall less precipitation, the pools will not get a chance to (i) properly form (ii) stay for over one season and (iii) support the soil [[Animals]] and microfauna that depend on these features for habitat.

===Lack of Research===
Vernal pools are not studied extensively, and as a result of this, humans are unintentionally destroying these important habitats. Research can help and may be the greatest proponent for these pools because they can prove their importance to the world. Researching every aspect of vernal pools is a necessity for their future conservation and restoration. Without the research, vernal pools will continue to face a serious decline, resulting in endangerment or extinction of fauna, plants, and natural services provided.

[[File: ArtificialPool.jpg|315px|right|thumb| [https://danieljhocking.wordpress.com/2014/07/22/creating-vernal-pools/] A completed vernal pool restoration project ]]

===Restoration===
Beyond the efforts of lawmakers charging fees for building, some restoration ecologists are designing faux pools to mitigate impacts of the disappearing, naturally occurring ones. There is an adaptive management approach that comes along with man-made vernal pools, as there is no way to assure working condition until they go through a subjective trial and error phase. These are considered as a last resort once the elimination of a natural pool is unavoidable.[[#5.|[5]]]

Documented projects and monitoring show that amphibian reproduction is severely inhibited and almost non-existent. The created wetlands tend to be more permanent than ephemeral, exposing larvae and breeders to more predators over time.[[#5.|[5]]] The improper hydrological regime in designed pools can be directly attributed to the failure of reproductive success with amphibians and other vernal pool breeders.[[#7.|[7]]]

==References==
1. Adams, Jill U. “Pooling Resources.” Science, vol. 350, no. 6256, 2 Oct. 2015, pp. 26–28., doi:10.1126/science.350.6256.26. [https://science-sciencemag-org.gate.lib.buffalo.edu/content/350/6256/26]

2. Baskin, Yvonne. "California's ephemeral vernal pools may be a good model for speciation." BioScience, vol. 44, no. 6, 1994, p. 384+. Science In Context, http://link.galegroup.com.gate.lib.buffalo.edu/apps/doc/A15536169/SCIC?u=sunybuff_main&sid=SCIC&xid=203d3f61. [http://go.galegroup.com.gate.lib.buffalo.edu/ps/retrieve.do?tabID=Journals&resultListType=RESULT_LIST&searchResultsType=MultiTab&searchType=BasicSearchForm&currentPosition=1&docId=GALE%7CA15536169&docType=Article&sort=Relevance&contentSegment=ZXBE-MOD1&prodId=SCIC&contentSet=GALE%7CA15536169&searchId=R2&userGroupName=sunybuff_main&inPS=true#]

3. Bauder, Ellen T. "Inundation effects on small-scale plant distributions in San Diego, California vernal pools." Aquatic Ecology 34.1 (2000): 43-61. [https://link.springer.com/article/10.1023/A:1009916202321]

4. Brown, Kathryn S. “Vanishing Pools Taking Species With Them.” Science, vol. 281, no. 5377, 1998, p. 626., doi:10.1126/science.281.5377.626a. [https://science-sciencemag-org.gate.lib.buffalo.edu/content/281/5377/626.1]

5. Calhoun, A. J. K., et al. “Creating Successful Vernal Pools: A Literature Review and Advice for Practitioners.” Wetlands, vol. 34, no. 5, 17 July 2014, pp. 1027–1038., doi:10.1007/s13157-014-0556-8. [https://link.springer.com/article/10.1007%2Fs13157-014-0556-8#citeas]

6. “California Vernal Pools.” VernalPools.Org - Plants & Animals of Vernal Pools, [https://www.vernalpools.org/species.htm]

7. Denton, Robert D., and Stephen C. Richter. “Amphibian Communities in Natural and Constructed Ridge Top Wetlands with Implications for Wetland Construction.” The Journal of Wildlife Management, vol. 77, no. 5, 2013, pp. 886–896., doi:10.1002/jwmg.543. [https://wildlife.onlinelibrary.wiley.com/action/showCitFormats?doi=10.1002%2Fjwmg.543]

8. Hocking, Daniel J. “Creating Vernal Pools.” Daniel J. Hocking, 22 July 2014, danieljhocking.wordpress.com/2014/07/22/creating-vernal-pools/. [https://danieljhocking.wordpress.com/2014/07/22/creating-vernal-pools/]

9. Montrone, Ashton, et al. “Climate Change Impacts on Vernal Pool Hydrology and Vegetation in Northern California.” Journal of Hydrology, 27 Apr. 2019, doi:10.1016/j.jhydrol.2019.04.076. [https://www.sciencedirect.com/science/article/pii/S0022169419304172]

10. Murtagh, Ed. “Vernal Pools.” Friends of Sligo Creek, Takoma Park Newsletter, Aug. 2004. [https://www.fosc.org/VernalPool.htm]

11. Thomas, S.A., Y. Lee, M. A. Kost, & D. A. Albert. 2010. Abstract for vernal pool. Michigan Natural Features Inventory, Lansing, MI. 24 pp [https://mnfi.anr.msu.edu/abstracts/ecology/vernal_pool.pdf]

12. “Vernal Pools.” EPA, Environmental Protection Agency, 6 July 2018, accessed 4 May 2019. [https://www.epa.gov/wetlands/vernal-pools]

13. “Vernal Pools.” Vernal Pools Animals, www.naturalheritage.state.pa.us/VernalPool_Geology.aspx. [https://www.naturalheritage.state.pa.us/VernalPool_Geology.aspx]

14. “Vernal Pool EarthCache.” GC2G67F Diamond Head Crater (Earthcache) in Hawaii, United States Created by Martin 5. [https://www.geocaching.com/geocache/GC6ZRQV_vernal-pool-earthcache?guid=451fa0e4-d882-4d81-936c-9e56bfb317ff]

File:Fairyshrimp.jpg

2019-05-08T02:26:38Z

Jennapec:

2019-05-04T06:29:11Z

Jennapec:

[[File:Roots1.jpg|275px|thumb|right|[http://www.biologydiscussion.com/root/tap-root-system/tap-root-system-definition-and-types-with-diagram/70193] Varying root sizes that are observed via root sampling]]

== Overview ==
Interest in root sampling was first stimulated on an ecological scale in 1960 by an ecologist testing soil water availability to plants[[#4.|[1]]]. Methods have been developed since that are able to produce both rough estimations and almost exact representations of root biomass. Rhizodeposition is a key factor in [[Plant establishment]] and these sampling methods become useful when gathering information on plant nutrient allocation and development. [[Rhizosphere]]s are highly variable in growth, so results from any root sampling method can be challenging to interpret.[[#5.|[2]]] It’s been estimated that in order to have a 90% confidence interval using any technique 40 or more samples must be taken, which is unfeasible for the majority of research purposes.[[#11.|[3]]]

=== Root Length Equation ===
=====[[File:Rootequation.JPG|250px|thumb|left|[https://www.jstor.org/stable/pdf/2401670.pdf?refreqid=excelsior%3Af987727f118cec3e6bcfcc38f93410fa]]]=====

Where '''''R''''' ''= total length of the root'', '''''N''''' ''= # of intersections between the root and straight lines'', '''''A''''' ''= area of the sampled rectangle'', and '''''H''''' ''= total length of the straight lines''. The line intersect method (including the root length equation) was created by E.I. Newman after he recognized that absorption of nutrients and water from the soil depends on root length and surface area rather than overall biomass.[[#8.|[4]]] Newman used various mathematical and ecological equations to derive this one specifically for complicated root systems so direct counting and measurement under a microscope can be avoided. Through this calculation, ecologists were able to precisely measure the root lengths contained in a system in one third of the time it took prior.[[#12.|[5]]] It holds importance as it was one of the first offering a quicker, more accurate approach to counting roots and fine root hairs.

== Uses for Root Sampling==
Root samples are useful for many agricultural, ecological, and educational purposes. Depending on the situation and ecosystem different methods may be preferred over others. Generally, root data is collected to analyze the overall health and development of a tree or plant.

With the increasing occurrence of habitat restoration projects and wildlife rehabilitation, root sampling is a vital management step to see the extent to which introduced plants have assimilated into new territory. [[Plant establishment]] will be checked at constant intervals after a site is designed, until the restoration efforts can be confirmed as successful. These experimental techniques allow the [[Rhizosphere]] of the modified ecosystems to be checked, and aid in detecting potential [[Ectomycorrhizal Fungi]] and [[Arbuscular Mycorrhizal Fungi]] connections.[[#11.|[6]]]

== Destructive Sampling Methods ==

===The Harvest Method===

[[File:Monolith.jpg|275px|thumb|left|[https://www.uidaho.edu/cals/soil-and-water-systems/research/pedology-laboratory/fosberg-monoliths] Monolith collection at the University of Idaho]]

The harvesting method is performed by extracting an undisturbed, vertical sample of ground soil and keeping it preserved in situ to examine the characteristics of the different soil [[Soil Horizons]]. First, the size of the desired sample must be determined and the auger to retract the soil must be chosen. These auger devices come in small, hand-held sizes or larger sizes which are mechanical and sometimes mounted on trucks.

The soil is either kept intact and preserved as a monolith or the roots in the sample are rinsed free of the soil particulates. Monoliths are created by cutting the cylindrical soil core in half and transferring one of the profiles to a solid surface, like ply board, using an acrylic bonding agent for mounting.[[#5.|[7]]][[#13.|[8]]] The other half not used for display purposes is used for lab sampling or classification purposes. Monoliths can be kept for decades if done correctly. When root samples are desired, a lot of water and patience is required. Roots are generally pre-soaked to minimize water usage, and in some cases dispersing chemicals are applied. (Barnett) Separated root samples can be stored up to 10 weeks, so it gives ample time for those studying the systems.

Despite this being considered a destructive sampling technique, it minimizes site disturbance while allowing a lot of valuable information to be gathered.[[#5.|[8]]]

===Root-Ingrowth===
[[File:mesh.jpg|300px|thumb|right|[http://www.clib-jena.mpg.de/theses/bgc/BGC12005.pdf] A dug up mesh bag with fine root hairs visibly grown in]]

The ingrowth method is beneficial in measuring the rate of growth for fine root hyphae (diameter <2 mm). It is very labor intensive and one of the more controversial root sampling procedures.[[#9.|[9]]] This is because (I) natural growth patterns can easily be altered chemically or physically (II) current roots are injured (III) growth starts after a period of delay (IV) decomposition rates are not considered and (V) artificial and low densities are recorded in the cores for the majority of the experiment.[[#15.|[10]]]

First, the chosen ground area in the root zone of plants is cored wide and deep enough to fit the parameters of the experiment. This coring is what cuts off living roots of present systems. Mesh, nylon bags are filled with sieved soil free of any root hairs or nodules, brought to the site, and inserted into the cored space. Women’s stockings can be used for a tight budget project. The mesh soil bags are left either long term or short term but must be kept buried long enough to allow for roots to transect and occupy the bag, typically at least 2 months.[[#9.|[11]]] After the bags are collected, the roots are separated from the adhered soil using methods such as the pre-soaking or dispersing chemicals that are also used in the Harvest Method (See above). Primary and secondary roots are left out to air dry while the fine root hyphae are oven dried at 50°C to constant weights.[[#15.|[12]]]

== Non-destructive Sampling Methods ==

===Rhizotrons===
[[File:Rhizotron1.jpg|200px|thumb|right|[https://www.nrs.fs.fed.us/research/facilities/rhizotron/about/] The Northern Research Station's rhizotron located in Houghton, Michigan]]

Rhizotrons are underground walkways with glass walls on other one, or both sides that expose the soil and living [[Rhizosphere]] surrounding the structure. These structures are special because they allow scientists to go inside and study the root systems that are still living and developing. Individual roots are easy to keep track of and measure which is great for succession and development research. A big limitation to this type of research is that large rhizotrons can be very costly to construct and operate.[[#10.|[13]]]

More advanced structures are designed to change the temperature, pH, and other elements of the surrounding soil, changing the observed [[Soil processes]] and root behaviors. Cameras are often mounted and set on time lapse in the observatory facing the roots to account for any changes such as diurnal swelling and shrinking[[#1.|[14]]] that scientists may miss unless they spent 24 straight hours collecting data.

Miniature versions of rhizotrons, not to be confused with minirhizotrons, are more commonly found as they are simple to make at little cost.

[[File:Minirhizotron.jpg|275px|thumb|right|[https://www.downtoearth.org.in/news/science-and-technology--briefs-34343] Minirhizotron diagram]]

===Minirhizotrons===

Minirhizotrons consist of a transparent tube that sometimes is designed with a reflective surface mounted to the inside of it. The tube is inserted in the root zone of the soil and a high resolution, thin camera is drawn through the tube. Once inside, the camera provides clear, in situ root images which can then be further used for quantitative data analysis by converting two-dimensional image data into three-dimensional root biomass data.[[#7.|[15]]] Minirhizotrons are similar to rhizotrons in that they allow for close-up study of root systems growing without human interaction or destruction.

The obtained images are used for comparative before and after shots and are greatly beneficial for analyzing restoration efforts. Minirhizotrons can monitor soil moisture, temperature, and water potential using tensiometers, time domain reflectometer probes, and matrix water potential sensors.[[#2.|[16]]] Monitoring the [[Water Behavior in Soils]] is important along with root development because the two are so closely related.

==Sources==
1. “Science.” Science, 4434th ed., vol. 207, American Association for the Advancement of Science, 1980, p. 975.

2. Cai, GC, et al. “Construction of Minirhizotron Facilities for Investigating Root Zone Processes.” VADOSE ZONE JOURNAL, vol. 15, no. 9, Sept. 2016, doi:10.2136/vzj2016.05.0043.

3. Elmajdoub, Bannur, et al. “Response of Microbial Activity and Biomass in Rhizosphere and Bulk Soils to Increasing Salinity.” Plant and Soil, vol. 381, no. 1-2, 2014, pp. 297–306., doi:10.1007/s11104-014-2127-4.

4. Gardener, W. R. “DYNAMIC ASPECTS OF WATER AVAILABILITY TO PLANTS.” SOIL SCIENCE, vol. 89, no. 2, Feb. 1960, pp. 63–73., journals.lww.com/soilsci/Citation/1960/02000/DYNAMIC_ASPECTS_OF_WATER_AVAILABILITY_TO_PLANTS.1.aspx.

5. Haddad, N.i., et al. “Improved Method of Making Soil Monoliths Using an Acrylic Bonding Agent and Proline Auger.” Geoderma, vol. 151, no. 3-4, 9 June 2009, pp. 395–400., doi:10.1016/j.geoderma.2009.05.012.

6. Johnson, Jane M.F., Morgan, Jack. “Sampling Protocols.” Plant Sampling Guidelines. IN Sampling Protocols, Ch. 2. R.F. Follett, editor. 2010, pp. 2-10. www.ars.usda.gov/research/GRACEnet

7. Lee, Chol Gyu, et al. “Estimation of Fine Root Biomass Using a Minirhizotron Technique among Three Vegetation Types in a Cool-Temperate Brackish Marsh.” Soil Science and Plant Nutrition, vol. 62, no. 5-6, 2016, pp. 465–470., doi:10.1080/00380768.2016.1205957.

8. Newman, E. I. “A Method of Estimating the Total Length of Root in a Sample.” Journal of Applied Ecology, vol. 3, no. 1, 1966, pp. 139–145. JSTOR, www.jstor.org/stable/2401670.

9. Steingrobe, Bernd, et al. “The Use of the Ingrowth Core Method for Measuring Root Production of Arable Crops – Influence of Soil and Root Disturbance during Installation of the Bags on Root Ingrowth into the Cores.” European Journal of Agronomy, vol. 15, no. 2, 5 Oct. 2001, pp. 143–151., doi:10.1016/s1161-0301(01)00100-9.

10. Taylor, H. M., et al. “Applications and Limitations of Rhizotrons and Minirhizotrons for Root Studies.” Plant and Soil, vol. 129, no. 1, 1990, p. 29.

11. Taylor, H.M. 1986. Methods of studying root systems in the field. Hortscience 21:952-956.

12. Tennant, D. “A Test of a Modified Line Intersect Method of Estimating Root Length.” Journal of Ecology, vol. 63, no. 3, 1975, pp. 995–1001. JSTOR, www.jstor.org/stable/2258617.

13. United States, Congress, Kiniry, Lauren N., and Conrad L. Neitsch. “Monolith Collection and Preparation For Soils without Restrictive Layers*.” Monolith Collection and Preparation For Soils without Restrictive Layers*, 1994.

14. Vanderford, C. F. "The soils of Tennessee. Univ. Tennessee Agr. Experiment Station." Bulletin 10.3 (1897): 1-139.

15. Xuefeng Li, Jiang Zhu, Holger Lange, Shijie Han, A modified ingrowth core method for measuring fine root production, mortality and decomposition in forests, Tree Physiology, Volume 33, Issue 1, January 2013, Pages 18–25, https://doi.org/10.1093/treephys/tps124

Root sampling methods

2019-05-04T05:36:07Z

Root sampling methods

2019-05-04T04:34:13Z

Jennapec: /* Minirhizotrons */

== Overview ==
Interest in root sampling was first stimulated on an ecological scale in 1960 by an ecologist testing soil water availability to plants(Gardener). Methods have been developed since that are able to produce both rough estimations and almost exact representations of root biomass. Rhizodeposition is a key factor in [[Plant establishment]] and these sampling methods become useful when gathering information on plant nutrient allocation and development. Root systems are highly variable in growth, so results from any root sampling method can be challenging to interpret.(Johnson) It’s been estimated that in order to have a 90% confidence interval using any technique 40 or more samples must be taken, which is unfeasible for the majority of research purposes. (Taylor)

=== Root Length Equation ===
=====[[File:Rootequation.JPG|250px|thumb|left|[https://www.jstor.org/stable/pdf/2401670.pdf?refreqid=excelsior%3Af987727f118cec3e6bcfcc38f93410fa]]]=====

Where '''''R''''' ''= total length of the root'', '''''N''''' ''= # of intersections between the root and straight lines'', '''''A''''' ''= area of the sampled rectangle'', and '''''H''''' ''= total length of the straight lines''. The line intersect method (including the root length equation) was created by E.I. Newman after he recognized that absorption of nutrients and water from the soil depends on root length and surface area rather than overall biomass. (Newman) Newman used various mathematical and ecological equations to derive this one specifically for complicated root systems so direct counting and measurement under a microscope can be avoided. Through this calculation, ecologists were able to precisely measure the root lengths contained in a system in one third of the time it took prior.(Tennant) It holds importance as it was one of the first offering a quicker, more accurate approach to counting roots and fine root hairs.

== Uses for Root Sampling==
Root samples are useful for many agricultural, ecological, and educational purposes. Depending on the situation and ecosystem different methods may be preferred over others. Generally, root data is collected to analyze the overall health and development of a tree or plant.

With the increasing occurrence of habitat restoration projects and wildlife rehabilitation, root sampling is a vital management step to see the extent to which introduced plants have assimilated into new territory. [[Plant establishment]] will be checked at constant intervals after a site is designed, until the restoration efforts can be confirmed as successful. These experimental techniques allow the [[Rhizosphere]] of the modified ecosystems to be checked, and aid in detecting potential [[Ectomycorrhizal Fungi]] and [[Arbuscular Mycorrhizal Fungi]] connections.(Barnett)

== Destructive Sampling Methods ==

===The Harvest Method===
The harvesting method is performed by extracting an undisturbed, vertical sample of ground soil and keeping it preserved in situ to examine the characteristics of the different soil layers. First, the size of the desired sample must be determined and the auger to retract the soil must be chosen. These auger devices come in small, hand-held sizes or larger sizes which are mechanical and sometimes mounted on trucks.(Barnett)

The soil is either kept intact and preserved as a monolith or the roots in the sample are rinsed free of the soil particulates. Monoliths are created by cutting the cylindrical soil core in half and transferring one of the profiles to a solid surface, like ply board, using an acrylic bonding agent for mounting. (Haddad)(Kiniry) The other half not used for display purposes is used for lab sampling or classification purposes. Monoliths can be kept for decades if done correctly. When root samples are desired, a lot of water and patience is required. Roots are generally pre-soaked to minimize water usage, and in some cases dispersing chemicals are applied. (Barnett) Separated root samples can be stored up to 10 weeks, so it gives ample time for those studying the systems.

Despite this being considered a destructive sampling technique, it minimizes site disturbance while allowing a lot of valuable information to be gathered.(Haddad)

===Root-Ingrowth===
The ingrowth method is beneficial in measuring the rate of growth for fine root hyphae (diameter <2 mm). It is very labor intensive and one of the more controversial root sampling procedures. (Steingrobe) This is because (I) natural growth patterns can easily be altered chemically or physically (II) current roots are injured (III) growth starts after a period of delay (IV) decomposition rates are not considered and (V) artificial and low densities are recorded in the cores for the majority of the experiment.(Li)

First, the chosen ground area in the root zone of plants is cored wide and deep enough to fit the parameters of the experiment. This coring is what cuts off living roots of present systems. Mesh, nylon bags are filled with sieved soil free of any root hairs or nodules, brought to the site, and inserted into the cored space. Women’s stockings can be used for a tight budget project. The mesh soil bags are left either long term or short term but must be kept buried long enough to allow for roots to transect and occupy the bag, typically at least 2 months. (steingrobe) After the bags are collected, the roots are separated from the adhered soil using methods such as the pre-soaking or dispersing chemicals that are also used in the Harvest Method (See above). Primary and secondary roots are left out to air dry while the fine root hyphae are oven dried at 50C to constant weights.(Li)

== Non-destructive Sampling Methods ==

===Rhizotrons===
[[Rhizotrons]] are underground walkways with glass walls on other one, or both sides that expose the soil and living [[Rhizosphere]] surrounding the structure. These structures are special because they allow scientists to go inside and study the root systems that are still living and developing. Individual roots are easy to keep track of and measure which is great for succession and development research. A big limitation to this type of research is that large rhizotrons can be very costly to construct and operate.(Taylor)

More advanced structures are designed to change the temperature, pH, and other elements of the surrounding soil, changing the observed [[Soil Processes]] and root behaviors. Cameras are often mounted and set on time lapse in the observatory facing the roots to account for any changes such as diurnal swelling and shrinking(Science mag) that scientists may miss unless they spent 24 straight hours collecting data.

===Minirhizotrons===
Minirhizotrons consist of a transparent tube that sometimes is designed with a reflective surface mounted to the inside of it. The tube is inserted in the root zone of the soil and a high resolution, thin camera is drawn through the tube. Once inside, the camera provides clear, in situ root images which can then be further used for quantitative data analysis by converting two-dimensional image data into three-dimensional root biomass data.(Lee) Minirhizotrons are similar to rhizotrons in that they allow for close-up study of root systems growing without human interaction or destruction.

The obtained images are used for comparative before and after shots and are greatly beneficial for analyzing restoration efforts. Minirhizotrons can monitor soil moisture, temperature, and water potential using tensiometers, time domain reflectometer probes, and matrix water potential sensors.(Cai)

==Sources==
“Science.” Science, 4434th ed., vol. 207, American Association for the Advancement of Science, 1980, p. 975.

Gardener, W. R. “DYNAMIC ASPECTS OF WATER AVAILABILITY TO PLANTS.” SOIL SCIENCE, vol. 89, no. 2, Feb. 1960, pp. 63–73., journals.lww.com/soilsci/Citation/1960/02000/DYNAMIC_ASPECTS_OF_WATER_AVAILABILITY_TO_PLANTS.1.aspx.

Johnson, Jane M.F., Morgan, Jack. “Sampling Protocols.” Plant Sampling Guidelines. IN Sampling Protocols, Ch. 2. R.F. Follett, editor. 2010, pp. 2-10. www.ars.usda.gov/research/GRACEnet

Newman, E. I. “A Method of Estimating the Total Length of Root in a Sample.” Journal of Applied Ecology, vol. 3, no. 1, 1966, pp. 139–145. JSTOR, www.jstor.org/stable/2401670.

Steingrobe, Bernd, et al. “The Use of the Ingrowth Core Method for Measuring Root Production of Arable Crops – Influence of Soil and Root Disturbance during Installation of the Bags on Root Ingrowth into the Cores.” European Journal of Agronomy, vol. 15, no. 2, 5 Oct. 2001, pp. 143–151., doi:10.1016/s1161-0301(01)00100-9.

Taylor, H. M., et al. “Applications and Limitations of Rhizotrons and Minirhizotrons for Root Studies.” Plant and Soil, vol. 129, no. 1, 1990, p. 29.

Taylor, H.M. 1986. Methods of studying root systems in the field. Hortscience 21:952-956.

Tennant, D. “A Test of a Modified Line Intersect Method of Estimating Root Length.” Journal of Ecology, vol. 63, no. 3, 1975, pp. 995–1001. JSTOR, www.jstor.org/stable/2258617.

United States, Congress, Kiniry, Lauren N., and Conrad L. Neitsch. “Monolith Collection and Preparation For Soils without Restrictive Layers*.” Monolith Collection and Preparation For Soils without Restrictive Layers*, 1994.

Vanderford, C. F. "The soils of Tennessee. Univ. Tennessee Agr. Experiment Station." Bulletin 10.3 (1897): 1-139.

Xuefeng Li, Jiang Zhu, Holger Lange, Shijie Han, A modified ingrowth core method for measuring fine root production, mortality and decomposition in forests, Tree Physiology, Volume 33, Issue 1, January 2013, Pages 18–25, https://doi.org/10.1093/treephys/tps124

Root sampling methods

2019-05-04T01:58:49Z

Jennapec:

== Overview ==
Interest in root sampling was first stimulated on an ecological scale in 1960 by an ecologist testing soil water availability to plants(Gardener). Methods have been developed since that are able to produce both rough estimations and almost exact representations of root biomass. Rhizodeposition is a key factor in [[Plant establishment]] and these sampling methods become useful when gathering information on plant nutrient allocation and development. Root systems are highly variable in growth, so results from any root sampling method can be challenging to interpret.(Johnson) It’s been estimated that in order to have a 90% confidence interval using any technique 40 or more samples must be taken, which is unfeasible for the majority of research purposes. (Taylor)

=== Root Length Equation ===
=====[[File:Rootequation.JPG|250px|thumb|left|[https://www.jstor.org/stable/pdf/2401670.pdf?refreqid=excelsior%3Af987727f118cec3e6bcfcc38f93410fa]]]=====

Where '''''R''''' ''= total length of the root'', '''''N''''' ''= # of intersections between the root and straight lines'', '''''A''''' ''= area of the sampled rectangle'', and '''''H''''' ''= total length of the straight lines''. The line intersect method (including the root length equation) was created by E.I. Newman after he recognized that absorption of nutrients and water from the soil depends on root length and surface area rather than overall biomass. (Newman) Newman used various mathematical and ecological equations to derive this one specifically for complicated root systems so direct counting and measurement under a microscope can be avoided. Through this calculation, ecologists were able to precisely measure the root lengths contained in a system in one third of the time it took prior.(Tennant) It holds importance as it was one of the first offering a quicker, more accurate approach to counting roots and fine root hairs.

== Uses for Root Sampling==
Root samples are useful for many agricultural, ecological, and educational purposes. Depending on the situation and ecosystem different methods may be preferred over others. Generally, root data is collected to analyze the overall health and development of a tree or plant.

With the increasing occurrence of habitat restoration projects and wildlife rehabilitation, root sampling is a vital management step to see the extent to which introduced plants have assimilated into new territory. [[Plant establishment]] will be checked at constant intervals after a site is designed, until the restoration efforts can be confirmed as successful. These experimental techniques allow the [[Rhizosphere]] of the modified ecosystems to be checked, and aid in detecting potential [[Ectomycorrhizal Fungi]] and [[Arbuscular Mycorrhizal Fungi]] connections.(Barnett)

== Destructive Sampling Methods ==

===The Harvest Method===
The harvesting method is performed by extracting an undisturbed, vertical sample of ground soil and keeping it preserved in situ to examine the characteristics of the different soil layers. First, the size of the desired sample must be determined and the auger to retract the soil must be chosen. These auger devices come in small, hand-held sizes or larger sizes which are mechanical and sometimes mounted on trucks.(Barnett)

The soil is either kept intact and preserved as a monolith or the roots in the sample are rinsed free of the soil particulates. Monoliths are created by cutting the cylindrical soil core in half and transferring one of the profiles to a solid surface, like ply board, using an acrylic bonding agent for mounting. (Haddad)(Kiniry) The other half not used for display purposes is used for lab sampling or classification purposes. Monoliths can be kept for decades if done correctly. When root samples are desired, a lot of water and patience is required. Roots are generally pre-soaked to minimize water usage, and in some cases dispersing chemicals are applied. (Barnett) Separated root samples can be stored up to 10 weeks, so it gives ample time for those studying the systems.

Despite this being considered a destructive sampling technique, it minimizes site disturbance while allowing a lot of valuable information to be gathered.(Haddad)

===Root-Ingrowth===
The ingrowth method is beneficial in measuring the rate of growth for fine root hyphae (diameter <2 mm). It is very labor intensive and one of the more controversial root sampling procedures. (Steingrobe) This is because (I) natural growth patterns can easily be altered chemically or physically (II) current roots are injured (III) growth starts after a period of delay (IV) decomposition rates are not considered and (V) artificial and low densities are recorded in the cores for the majority of the experiment.(Li)

First, the chosen ground area in the root zone of plants is cored wide and deep enough to fit the parameters of the experiment. This coring is what cuts off living roots of present systems. Mesh, nylon bags are filled with sieved soil free of any root hairs or nodules, brought to the site, and inserted into the cored space. Women’s stockings can be used for a tight budget project. The mesh soil bags are left either long term or short term but must be kept buried long enough to allow for roots to transect and occupy the bag, typically at least 2 months. (steingrobe) After the bags are collected, the roots are separated from the adhered soil using methods such as the pre-soaking or dispersing chemicals that are also used in the Harvest Method (See above). Primary and secondary roots are left out to air dry while the fine root hyphae are oven dried at 50C to constant weights.(Li)

== Non-destructive Sampling Methods ==

===Rhizotrons===
[[Rhizotrons]] are underground walkways with glass walls on other one, or both sides that expose the soil and living [[Rhizosphere]] surrounding the structure. These structures are special because they allow scientists to go inside and study the root systems that are still living and developing. Individual roots are easy to keep track of and measure which is great for succession and development research. A big limitation to this type of research is that large rhizotrons can be very costly to construct and operate.(Taylor)

More advanced structures are designed to change the temperature, pH, and other elements of the surrounding soil, changing the observed [[Soil Processes]] and root behaviors. Cameras are often mounted and set on time lapse in the observatory facing the roots to account for any changes such as diurnal swelling and shrinking(Science mag) that scientists may miss unless they spent 24 straight hours collecting data.

===Minirhizotrons===
Minirhizotrons are hand held, transparent devices similar to rhizotrons in that they allow visible access to root systems. They come in either rectangular or tube shapes(steingrobe) with the subject planted inside of it.

==Sources==
“Science.” Science, 4434th ed., vol. 207, American Association for the Advancement of Science, 1980, p. 975.

Gardener, W. R. “DYNAMIC ASPECTS OF WATER AVAILABILITY TO PLANTS.” SOIL SCIENCE, vol. 89, no. 2, Feb. 1960, pp. 63–73., journals.lww.com/soilsci/Citation/1960/02000/DYNAMIC_ASPECTS_OF_WATER_AVAILABILITY_TO_PLANTS.1.aspx.

Johnson, Jane M.F., Morgan, Jack. “Sampling Protocols.” Plant Sampling Guidelines. IN Sampling Protocols, Ch. 2. R.F. Follett, editor. 2010, pp. 2-10. www.ars.usda.gov/research/GRACEnet

Newman, E. I. “A Method of Estimating the Total Length of Root in a Sample.” Journal of Applied Ecology, vol. 3, no. 1, 1966, pp. 139–145. JSTOR, www.jstor.org/stable/2401670.

Steingrobe, Bernd, et al. “The Use of the Ingrowth Core Method for Measuring Root Production of Arable Crops – Influence of Soil and Root Disturbance during Installation of the Bags on Root Ingrowth into the Cores.” European Journal of Agronomy, vol. 15, no. 2, 5 Oct. 2001, pp. 143–151., doi:10.1016/s1161-0301(01)00100-9.

Taylor, H. M., et al. “Applications and Limitations of Rhizotrons and Minirhizotrons for Root Studies.” Plant and Soil, vol. 129, no. 1, 1990, p. 29.

Taylor, H.M. 1986. Methods of studying root systems in the field. Hortscience 21:952-956.

Tennant, D. “A Test of a Modified Line Intersect Method of Estimating Root Length.” Journal of Ecology, vol. 63, no. 3, 1975, pp. 995–1001. JSTOR, www.jstor.org/stable/2258617.

United States, Congress, Kiniry, Lauren N., and Conrad L. Neitsch. “Monolith Collection and Preparation For Soils without Restrictive Layers*.” Monolith Collection and Preparation For Soils without Restrictive Layers*, 1994.

Vanderford, C. F. "The soils of Tennessee. Univ. Tennessee Agr. Experiment Station." Bulletin 10.3 (1897): 1-139.

Xuefeng Li, Jiang Zhu, Holger Lange, Shijie Han, A modified ingrowth core method for measuring fine root production, mortality and decomposition in forests, Tree Physiology, Volume 33, Issue 1, January 2013, Pages 18–25, https://doi.org/10.1093/treephys/tps124

Hydrophobic soil

2019-05-03T03:23:38Z

Jennapec:

[[File:wd.png|275px|thumb|right|[https://aussiegreenthumb.com]
Water droplets repelled by hydrophobic soil]]

== Definition & Entomology ==

The term “hydrophobic” stems from the Greek prefix- ''hudōr'', ‘water’ and the Latin and Greek suffix- ''-φοβία'', ‘-phobía’. It is biologically defined as tending to repel or mix with water. Hydrophobicity is introduced as a property of soils when waxy, organic substances coat the surface area of soil particles, essentially making the soil impenetrable by any precipitation or other liquids. This water repellent layer is highly variable in effects depending on where the given site is.

[[File:triangle.png|250px|thumb|left| [https://researchgate.net]

Soil textural classification triangle]]

== Distribution ==

Hydrophobic soils are expected to be more prevalent in hot, temperate climates[[#9.|[1]]] in soils predominately composed of [[Sand]] (<5% [[Clay]]). The increased particulate surface area of sand, sandy loam, and loamy sand soils create the most attraction with organic substrates out of all soil classifications. The insoluble compounds that induce this phenomenon are allocated in the [[Vegetable Mould]] and [[Humus]] layers of the various [[Soil Horizons]]. Water repellent soils have been located in all western and southwestern parts of the United States, Canada, Finland[[#9.|[2]]], Australia[[#10.|[3]]], Portugal[[#5.|[4]]], Columbia[[#6.|[5]]], Greece[[#13.|[6]]] and is abundant in many parts of the world. Water repellent soils can be found on all continents excluding Antarctica.

Fertilizer use in both household and large-scale agricultural settings can accidentally induce water-repellency of soil regardless of temporal region. Treatments containing calcium or magnesium hydroxide especially have been shown to mix with the fatty acids of soils, creating insoluble molecules[[#11.|[7]]].

== Effects ==

===Wildfires===

[[File:debano.gif|300px|thumb|right|[http://www.fsl.orst.edu/ltep/Biscuit/Biscuit_files/Refs/DeBano%20JH2000b%20fire.pdf]
The role of fire and soil heating on water repellency]]

Landscapes with hydrophobic soil elements are vulnerable to catching on fire. The soil particles are deprived of water making the soil dense and extremely dry. Soil moisture is one of the most important factors when considering [[Decomposition]] of organic matter, so with decreased soil moisture there is respectively less decomposition occurring.

In forested biomes, the huge biomass stock of leaf litter and anthropogenically placed mastification[[#2.|[8]]] deposits on the forest floor acts as fuel for fire and responds quickly to ignition. Needle leaf trees such as those included in the pine (''Pinus''), spruce (''Picea''), and hemlock (''Tsuga'') genera speed up the hydrophobic process as well when their needles fall and gather on the ground creating buildups of litter. Fire breaking out in these areas causes the wax substrate from all of the collective needles to melt into a relatively thick hydrophobic wax layer below the surface of the soil. A ground surface that had little to no water repellency before a fire will show increased amounts of water repellency post-fire, creating a positive loop between fires and hydrophobicity.

===Erosion & Runoff===

With the loss of above ground biomass caused by forest fires, stunted growth and development of flora, and the water repellent layer in itself, natural hydrological processes of an ecosystem accelerate. Decreased root biomass and overall decrease in above ground coverage following a forest fire expose the soil to weathering and erosion. Hydrophobic soil layers will stop the infiltration of rainwater causing it to either remain stagnant or flow downstream, depending on the slope of the site. In instances following a wildfire, runoff has been shown to increase up to 4x the normal amount and continues for two vegetation seasons or until the effects of the fire wear off. [[#8.|[9]]]

The increased erosion and runoff rates can induce flooding and sediment transport to downstream communities and ecosystems, especially in the aftermath of fire[[#8.|[9]]]. Water repellent soil will cause hydrological processes to occur but fires worsen the effects by removing natural barriers, such as broken tree limbs, which would normally act as speed bumps for runoff precipitation. Runoff flowing through burned areas picks up ash and debris which contain highly soluble nutrients[[#4.|[10]]], sending them downstream through water channels.

===Plant Establishment===

[[File:fairyring.jpg|200px|thumb|right|[https://www.pinterest.com/pin/285063851393783403/?lp=true]
A fairy ring prior to desiccation]]

Areas where fungal mycelia once dominated will result in hydrophobic, bare patches of soil. The mycelia rapidly stimulate fungal growth, exhausting the soil of its water content. After the sprouts dry and die off, the soil that was beneath them becomes water repellent and inhibits growth of any grasses or plant that was present before they arrived- this was first described as the fairy ring phenomenon[[#7.|[11]]]. Folklore prior to scientific investigation states that these are the spots where dancing fairies once were, the footpath of dragons, or “where the devil churned his butter”[[#4.|[12]]].

Water repellency makes it extremely difficult for seeds to germinate and grow. The non-absorbent layer has little water content to offer new seedlings that require optimal levels through germination and initial growth stages. In addition to this, seeds may also be carried off of the site with the hydrophobically induced runoff, severely decreasing the chance of seed and [[Plant establishment]][[#4.|[13]]]. Smaller seeds and larger slopes result in the highest rate in reduction of soil water availability. The seeds that end up settling into the soil must compete at greater levels with same and differing species for limited nutrients.

== Treatment and Sampling ==

[[File:Clay.jpg|260px|thumb|left| [http://soilquality.org.au/factsheets/water-repellency]
the difference in growth on clay-treated soil (7% clay) vs. untreated soil (0.5% clay)]]

The most commonly documented treatment of hydrophobic soil is done by adding moisturizing clay agents in a process referred to simply as “claying”. Because the most vulnerable soils tend to be sand-based, clay mixtures aid the soil its being added to by allowing water and nutrient retention to occur[[#1.|[14]]]

To determine if a soil site must undergo treatment, a few things must be determined regarding the sample. The first and most straight-forward method of testing for general hydrophobicity is the Water Drop Penetration Time (WDPT) test- where 1-3 droplets of distilled water are placed directly onto a smooth soil surface and measured for rate of absorption. For general scale, a resulting time of 5 seconds or greater classifies the sample as "hydrophobic". Initial water intake of wettable soil occurs rapidly because of the strong attraction between the water molecules and dry soil aggregates [[#4.|[15]]]. However, the water infiltration rate of repellent soils is either very slow or non-existent. Therefore, repellent soil will cause naturally occurring precipitation and the experimental water droplet to bead on top of the sample, if or until it is completely absorbed. This test is best performed under dry climatic periods to attain the highest possible hydrophobic qualities that may occur in the field. The values obtained for this experiment are measured by ''absorption per parameter of time'' [cm/s] or ''percentage'' [%][[#13.|[16]]].

Determining the textural classification of the soil sample is common for scientific and research purposes. Tools such as sieves and hydrometers are most typically used in [[Soil Particle Size Analysis Methods]] to determine what percent sand, silt, and clay are held in the soil. The USDA's [[#Soil textural classification triangle|Soil textural classification triangle]] is used to determine the type of soil once the sample is tested for particle ratios.

== Sources ==
1. “ Effects of Organic Compounds, Water Content and Clay on the Water Repellency of a Model Sandy Soil.” Soil Science and Plant Nutrition, vol. 53, no. 6, Dec. 2007.

2. Busse, Matt D., et al. “Lethal Soil Temperatures during Burning of Masticated Forest Residues.” International Journal of Wildland Fire, vol. 14, 2005, pp. 267–276., doi:https://www.fs.fed.us/psw/publications/busse/psw_2005_busse001_ijwf.pdf.

3. Cesarano, Gaspare. “The Influence of Plant Litter on Soil Water Repellency: Insight from 13C NMR Spectroscopy.” PloS One, vol. 11, no. 3, Mar. 2016.

4. DeBano, Leonard F. “Water Repellent Soils: a State-of-the-Art.” United States Department of Agriculture Forest Service Pacific Southwest Forest and Range Experiment Station: General Technical Report PSW-4, Mar. 1981, pp. 4–20.

5. Doerr, S.H., et al. “Soil Water Repellency: Its Causes, Characteristics and Hydro-Geomorphological Significance.” Earth Science Reviews, vol. 51, no. 1-4, Aug. 2000, pp. 33–65.

6. Jurez, Laura Daniela, et al. “Stabilization of Colombian Lateritic Soil with a Hydrophobic Compound (Organosilane).” International Journal of Pavement Research and Technology, vol. 11, no. 6, Nov. 2018, pp. 639–646., apps.webofknowledge.com.gate.lib.buffalo.edu/CitedFullRecord.do product=WOS&colName=WOS&SID=8DQlpZIc13phMJI24Hm&search_mode=CitedFullRecord&isickref=WOS:000087736400012.

7. Nieves-Rivera, Angel M. "The fellowship of the rings: UFO rings versus fairy rings: fungal diseases, mushrooms, fairy rings (a fungus ring), bioluminescent fungi, and slime molds are presented as possible explanations for some UFO rings or 'landing rings.'." Skeptical Inquirer, Nov.-Dec. 2003, p. 50+. Science In Context, http://link.galegroup.com.gate.lib.buffalo.edu/apps/doc/A110575766/SCIC?u=sunybuff_main&sid=SCIC&xid=05479006. Accessed 29 Apr. 2019.

8. Pierson, Frederick B., et al. “Impacts of Fire on Hydrology and Erosion in Steep Mountain Big Sagebrush Communities.” International Journal of Wildland Fire, vol. 11, no. 2, 2003, p. 145., doi:https://www.fs.fed.us/rm/pubs_other/rmrs_2003_robichaud_p001.pdf.

9. Rasa, Kimmo, et al. “Water Repellency of Clay, Sand and Organic Soils in Finland.” AGRICULTURAL AND FOOD SCIENCE, vol. 16, 2007, pp. 267–277.

10. Robichaud, P.R., et al. “A Probabilistic Approach to Modeling Postfire Erosion after the 2009 Australian Bushfires.” 18th World IMACS / MODSIM Congress, July 2009, pp. 1–7.

11. Wander, I. W. “An Interpretation of the Cause of Water-Repellent Sandy Soils Found in Citrus Groves of Central Florida.” Science, vol. 110, no. 2856, 1949, pp. 299–300., doi:10.1126/science.110.2856.299.

12. White, Carleton S. “Homogenization of the Soil Surface Following Fire in Semiarid Grasslands.” Rangeland Ecology and Management, vol. 64, no. 4, 2011, pp. 414–418.

13. Ziogas, Apostolos K., et al. "Soil water repellency in north-eastern Greece with adverse effects of drying on the persistence." Australian Journal of Soil Research, vol.
43, no. 3, 2005, p. 281+. Science In Context, http://link.galegroup.com.gate.lib.buffalo.edu/apps/doc/A133910175/SCIC?u=sunybuff_main&sid=SCIC&xid=2238eb00. Accessed 25 Apr. 2019.

Root sampling methods

2019-05-03T03:22:04Z

Jennapec:

Root sampling methods

2019-05-02T02:28:53Z

Jennapec:

Root sampling methods

2019-05-01T00:26:36Z

Jennapec:

== Overview ==
Interest in root sampling was first stimulated on an ecological scale by testing soil water availability to plants in 1960(Gardener). Methods have been developed since that are able to develop both rough estimations and almost exact representations of root biomass. Rhizodeposition is a key factor in [[Plant establishment]] and these sampling methods become useful when gathering information on plant nutrient allocation and overall health.

=== Root Length Equation ===
=====[[File:Rootequation.JPG|250px|thumb|left|[https://www.jstor.org/stable/pdf/2401670.pdf?refreqid=excelsior%3Af987727f118cec3e6bcfcc38f93410fa]]]=====

Where '''''R''''' ''= total length of the root'', '''''N''''' ''= # of intersections between the root and straight lines'', '''''A''''' ''= area of the sampled rectangle'', and '''''H''''' ''= total length of the straight lines''. The root length equation was created by E.I. Newman after he recognized that absorption of nutrients and water from the soil depends on root length and surface area rather than overall biomass. (Newman) Newman used various mathematical and ecological equations to derive this one specifically for complicated root systems so direct counting and measurement under a microscope can be avoided. It holds importance as it was one of the first offering a quicker, more accurate approach to counting roots and fine root hairs.

== Uses for Root Sampling==
Root samples are useful for many agricultural, ecological, and educational purposes.

== Destructive Sampling Methods ==
===The Harvest Method===
===Monoliths===
===Root-Ingrowth===

== Non-destructive Sampling Methods ==
===Rhizotrons===
===Minirhizotrons===

==Sources==
Gardener, W. R. “DYNAMIC ASPECTS OF WATER AVAILABILITY TO PLANTS.” SOIL SCIENCE, vol. 89, no. 2, Feb. 1960, pp. 63–73., journals.lww.com/soilsci/Citation/1960/02000/DYNAMIC_ASPECTS_OF_WATER_AVAILABILITY_TO_PLANTS.1.aspx.
Newman, E. I. “A Method of Estimating the Total Length of Root in a Sample.” Journal of Applied Ecology, vol. 3, no. 1, 1966, pp. 139–145. JSTOR, www.jstor.org/stable/2401670.

2019-04-26T15:50:49Z

Jennapec: