L10. Review Quiz

Soil profile

a vertical section of the soil through all its horizons and extending into the original, parent material.

Spodosols will most likely develop under which type of vegetation? Question options: rainforest savanna mosses and lichens conifers

conifers

Aridisols

form in arid and semi- arid landscapes and are characterized by a thin or absent A horizon. The lack of moisture and, thus, vegetation, leads to poor soil development. A cycling of salts in the soil profile may result in a sodium-rich (salic) horizon, which is toxic to most plants. Thus, the vegetation will die.This often occurs in low-lying spots or valleys on the landscape where water collects and later evaporates. In the United States, Aridisols are found in the western Great Plains and the southwest.

soil color

gray soil colors (called gleyed): occur when soil is poorly drained or has too much water yellow, orange, or red soil colors: occur when soil is well drained or aerated (has plenty of air) and/or is rich in iron dark brown or black soil colors: occur when soil is rich in SOM white accumulations in soil: can occur when soil has a high carbonate or salt content white zones or horizons in soil: can occur when a soil's mineral material is essentially clean (that is, uncoated/unstained), especially if grains are quartz

A soil forms _______ parent material. Question options: over in around below

in

Salinization is most likely to occur: Question options: any environment where agriculture is present. in a humid environment where pine trees are present. in a semiarid environment where there is irrigated agriculture. any environment that is hot and receives ample precipitation.

in a semiarid environment where there is irrigated agriculture. (L.9 pg 9)

The thickest, most developed soil would most likely form in the least amount of time under which of the following conditions? Question options: an arid climate with small, low-lying vegetation in a hilly landscape with a cold, moist climate a semi-arid climate with sparse vegetation in a well-vegetated flat region with a humid climate

in a well-vegetated flat region with a humid climate

If a soil does not have a colloidal fraction, that is, organic matter and clays: Question options: cations (minerals) will be held by plant roots until more colloids form. more cations (minerals) will be absorbed by plants for use. more cations (minerals) are likely to be leached out of the soil. it will have higher fertility.

more cations (minerals) are likely to be leached out of the soil.

A mole (burrowing macrofauna) spends its entire life in tunnels it digs within the soil of a backyard. Which of the following about this statement is false? Question options: It is an example of pedoturbation. It describes one of the essential functions of a soil. The mole will add organic matter to the soil when it dies. Moles are a soil disturbance and the soil will not properly form.

Moles are a soil disturbance and the soil will not properly form.

Mollisols

Mollisols are prairie soils that form in association with calcification. Calcification occurs in regions that have a fairly good moisture supply, or at least enough moisture to support thick stands of grass, yet experience a slight moisture deficit for part of the year so that minerals are not leached out of the soil profile. A second process that is common in Mollisols, is melanization. As plants grow in a soil, litter accumulates on the soil surface. As the litter decomposes it turns into humus (remember this is soil organic matter), which washes into the soil and is mixed with the mineral material by soil fauna, such as earthworms and rodents.The mixed humus coats soil particles and makes them appear dark, hence the term melanization, which means to make dark. In doing so, the soil develops a dark surface layer called the A horizon. Humus and, therefore, the A horizon that develops, is a tremendous storehouse of nutrients. As you may remember from the soil distribution map, Mollisols are found in regions dominated by grassland vegetation (prairies) like the United States Midwest and Great Plains. Grasses decompose slowly in these environments and have a dense underground root system that contributes to the high organic matter content and calcium in these soils. Soil animals, like earthworms, ants, and moles, mix the soils carrying organic matter deeper below the surface. Mollisols therefore have a very thick, humus-rich A horizon that is dark in color.

Oxisols

Oxisols are weathered soils formed by laterization in the equatorial and tropical regions of the world. In Oxisols, most minerals are removed except for iron and aluminum, which are not as soluble, resulting in an oxic horizon that is reddish in color. Oxisols tend to have low fertility because most minerals have been removed from the soil profile. In hot, wet climates, weathering of soil minerals is very fast and their byproducts (bases) are quickly leached from the soil. In the absence of a litter layer (litter decomposes quickly in warm, wet environments) few organic acids are produced. Sesquioxides--iron and aluminum--are insoluble and accumulate in the soil as red clays, nodules, or rock-like layers (called laterite).

Alfisols

Similar to Spodosols, Alfisols are forest soils that have a well-developed E horizon , which is ashy-gray in color (that is, an albic horizon), a reddish-brown B horizon (that is, a spodic horizon), and an argillic (Bt) horizon, which is high in illuvial clay content. Alfisols form in moist environments mostly under deciduous forest vegetation, but coniferous trees may be present as well. They are less-heavily leached and form in cooler environments than those found in tropical and sub-tropical environments and have a higher concentration of bases than those found poleward (that is, Spodosols).

Name the four most general pedogenic processes.

Soil additions, Soil depletions, Translocations, Transformations (pg. 268)

soil fauna

Soil fauna include all animals that spend at least part of their life in the soil: mites, nematodes, protozoans, pot worms, springtails, mollusks, millipedes, ants, earthworms, termites, moles, crayfish, gophers, et cetera.

soil flora

Soil flora include all non-animal organisms that spend at least part of their life in the soil: bacteria, actinomycetes, fungi, algae, plant roots, et cetera.

Soil mineral material

Soil minerals are naturally occurring chemical elements or compounds that possess a crystalline structure and are the constituents of rocks. Some of the most common minerals are silicon, aluminum, iron, calcium, potassium, and magnesium.

Regolith

the loose, unconsolidated mantle of weathered rock and soil material at the earth's surface.

essential functions of soil typically fall into one of the five categories listed below.

(1) A medium for the growth of plants (2) Regulator and purifier of water in the water supply (3) Recycler of raw-materials by decomposing organisms and biological material, and stores/reuses it (4) A habitat for organisms (5) Supporter of the anthropogenic ecosystem as an engineering medium

The five soil-forming factors are:

(1) parent material, (2) climate, (3) organisms, (4) topography, and (5) time.

Because all soils are not the same, they will have different percentages of each component

(1) when air > water - - - have a dry soil (2) when water > air - - - have a wet soil (3) when mineral > organic matter - - - have a mineral soil (4) when organic > mineral matter - - - have an organic soil

You are traveling through the Cascade volcanic arc of the Pacific Northwest, United States. Which soil order would you expect to be found there? Question options: Histosols Andisols Gelisols Ultisols

Andisols (L9 pg 8, 11, 12)

Andisols

Andisols are volcanic soils that are formed in volcanic materials, such as ash or lava, from active or extinct volcanoes. Volcanic materials are rich in bases, so they have high availability of plant nutrients. They have an abundance of carbon, which can give them a dark, sometimes black, appearance. Andisols are ideal for growing crops. The fertile, volcanic soils of the landscape around Mount Vesuvius (near Naples, Italy) have long been important to agriculture in that region.

Entisols

Entisols are young soils that have experienced relatively little soil development. If an A horizon is present it is thin and overlies the C horizon, which you may remember is the unaltered parent material. The lack of development in Entisols may be due to a number of reasons, including the age of the soil, climate, or the type of parent material present. Further the geographic distribution is somewhat random, as Entisols can be found at any latitude.

soil orders

Gelisols -soils that are permanently frozen within 2 meters of the surface -very cold climates Histosols -organic soils -areas with poor drainage Spodosols -acid soils with an accumulation of Fe- and Al- humus complexes -cool, moist climates under (coniferous) forests Andisols -soils formed in volcanic ash -areas of volcanic activity Oxisols -intensely weathered soils of tropical and subtropical environments -tropics and subtropics Vertisols -clayey soils with the ability to significantly shrink/swell when dry/wet -occur on every continent, except Antarctica Aridisols -calcium carbonate-containing soils of arid environments with well-developed horizons -arid and semi-arid climates Ultisols -soils with a zone of silicate clay accumulation and relatively low fertility -humid temperate and subtropical/tropical areas under forests Mollisols -grassland soils with high cation content -midlatitude grasslands (prairies) Alfisols -soils with a zone of silicate clay accumulation and relatively high fertility -temperate humid and subhumid areas under forests Inceptisols -soils with weakly developed horizons; often young soils -occur in a wide range of environmental settings, especially on steep slopes, young landscapes, and resistant parent materials Entisols -soils with little or no development; often young and/or infertile soils -occur in a wide range of environmental settings (essentially considered unaltered parent material)

Gelisols

Gelisols are permafrost-affected soils that are found in very cold climates of high-latitude polar regions and localized areas at high mountain elevations. These soils experience low soil temperatures that slow the decomposition of organic matter, making Gelisols organic-rich soils. Their frozen condition makes these soils very sensitive to human activities, such as vehicle traffic or construction. Photographing a Gelisol is particularly challenging. Once the soil pit is dug, you have a very short time to prepare the pit face for photographing before it melts (much like ice cream!).

Soil air

Generally, soil air has a higher CO2 content and lower oxygen content than our atmosphere due to all of the soil fauna respiring (that is, taking in oxygen and releasing carbon dioxide). Soil air is needed for healthy soil organisms, plants and animals, which aid in many other soil functions.

Histosols

Histosols are organic soils that have more organic matter than mineral matter in all horizons. Typically, Histosols form in moist, cool environments, similar to spodosols. That said, Histosols are commonly associated with wet terrestrial environments, like wetlands and bogs. The increased organic matter is prevalent with these soils because decomposition is inhibited by wetness and cool temperatures. Gleization, or gleying, is a characteristic of poorly drained (but not saline) environments under moist, cool climates. Wet soils are usually gleyed to some degree. Cool temperatures slow the decomposition of the litter that falls on the soil surface and thick O- and A-horizons may form. A series of complex chemical reactions involving different forms of iron, which turn the soil in the saturated (wet) zone from red to gray. Within a soil profile, zones of fluctuating water conditions (wet, saturated vs. dry, aerated) often have patches of red/orange and gray (called redoximorphic features). In other words, these soil horizons appear mottled in color, while the horizons in the totally saturated zone below appear gray.

Inceptisols

Inceptisols are weakly developed soils that are similar to Entisols, but have a B horizon. Inceptisols can be found in areas with recently deposited or disturbed sediments, eroded sites, or formed in parent material that is not easily weathered.

general patterns

Soil order Location Reason Aridisols Southwest United States Arid climate Andisols Northwest United States and Hawaii Volcanic activity (the Pacific's Ring of Fire) Alfisols Midwest Forest vegetation and relatively young soil (due to history of glaciation). Mollisols Midwest and the Great Plains Grasslands/prairie vegetation Ultisols Southeast United States Forest vegetation and relatively old and weathered soil Spodosols Great Lakes region and the Northeast United States Cool and moist climate and coniferous forest vegetation Gelisols Alaska Cold for much of the year

Soil organic material

Soil organic material (SOM) comes from decomposing organisms (by bacteria or fungi) and biological material that are slowly incorporated into the soil. SOM is an important source of carbon and plays a very important role in soil's biochemical processes. It is also glue-like, which helps to hold mineral material together and helps to hold water in the soil. SOM is described by how decomposed it is: fresh (litter; source of organic matter is recognizable); or rotten (humus (not to be confused with the hummus you eat); its source is not recognizable; appears like a black ooze).

Soil water

Soil water is needed for plant growth. Both nutrients and organisms move around the soil in its water. Water is also important for the chemical processes occurring within the soil such as weathering and leaching (more on this later). Soil water helps determine how acidic a soil is (that is, it helps to determine a soil's pH). Soil pH influences: the kinds of fauna that can survive in a soil; mineral weathering; and which nutrients are available to be used by plants.

Spodosols

Spodosols are acidic soils that form by podzolization in cool, humid regions, often in sandy parent material. Podzolization occurs as a needle-leaf litter layer (O horizon) left by coniferous trees such as pines causes infiltrating soil water to become acidic. This acidic water mobilizes and translocates bases (calcium, potassium, et cetera) from the soil.

Ultisols

Ultisols are weathered soils that are similar to oxisols in color and base content. They tend to be less weathered and, therefore, more fertile than Oxisols, but more weathered and less fertile than Alfisols. Another difference between Ultisols and Oxisols is clay content. Ultisols have a distinct argillic horizon, rich in translocated clays. They can support agriculture when fertilizer is used. In the United States, Ultisols are found in areas of relatively high rainfall and warm temperatures like in the Southeast.

Vertisols

Vertisols are clay-rich (shrink-swell) soils that form through geomechanical processes associated with cycles of shrinking, when dry, and swelling, when wet. When the soil shrinks, deep cracks can form in the ground. As a result of this shrink-swell action, Vertisols are destructive to buildings and structures that have not been built with the soil's properties in mind. From a geographic perspective, Vertisols are not widespread and their presence is limited to areas with clay-rich parent material. Globally, the largest regions of Vertisols are found in the tropics and subtropics.

soil

While some consider the soil strictly part of the lithosphere, we will treat it as a transitional feature between the bio- and litho-spheres. Soil plays an important role in both spheres, as it influences many elements of the biosphere and is influenced by the lithosphere in which it forms. a zone at the Earth's surface with a distinctive organization of mineral, organic matter, and pore space. Soil is created by the dynamic interactions of biological, chemical, and physical processes. Soil is a very complex, natural system: one that plays an integral role in the global environment and has a significant impact on both the physical and cultural landscapes. The soil zone (horizon) varies in thickness from a few centimeters to several meters. about 50% solid matter and 50% pore space. More specifically, an ideal soil is about 45% mineral matter and 5% organic matter (the solids) and 25% air and 25% water

Soil horizon

a distinctly recognizable layer (different from other adjacent layers) of soil that is approximately parallel to the land's surface.

Tubers are plant organs that typically grow and mature underground, such as yams or potatoes. Which soils structure would most easily allow a tuber to navigate through the spaces between grains? Question options: a platy structure a blocky structure a granular structure a prismatic structure

a granular structure

Which of the following is the name for the specific (regional) soil-forming process that occurs in tropical locations and results in weathered, iron-rich soils with a reddish color? Question options: salinization ionization calcification None of the options below are correct. laterization

not ionization, not none of the options below are correct (L9 pg 9) i think calcification

Based on what you know about soil development, more translocations (eluviation and illuviation) will occur in a soil: [Tip: Read each foil carefully and select the best answer.] Question options: in a dry climate, where calcium carbonate is present. on a relatively level landscape in a moist climate. on a mountain slope in a cool, moist climate. under trees with acidic leaf litter in a dry climate.

on a relatively level landscape in a moist climate (L9 pg 7)

Name that soil. Formed under tropical rainforest vegetation, this soil has low fertility and appears reddish due to iron accumulation. Question options: alfisol oxisol spodosol gelisol

oxisol

You are on an ecotour through the tropical rainforest of Costa Rica. Which soil order would you most likely find there? Question options: Alfisols Spodosols Oxisols Ultisols

oxisols

Six pedogenic regimes:

podzolization salinization calcification laterization melanization gleization

A soil is used as support for a building and as an agriculture field. In this case, the soil is: Question options: not a natural body. declining in quality and structure. no longer forming or developing. serving one of its essential functions.

serving one of its essential functions.

Clay, silt, and sand are: Question options: soil particles listed from smallest to largest. all different soil colors. never present in the same soil. examples of soil structure.

soil particles listed from smallest to largest. (L9 pg 7)

You are an environmental consultant collecting soil samples from a potential building site. You send the samples to a lab for particle-size analysis. The lab results indicate Sample 1 is 20% sand, 20% silt, and 60% clay. You can use this lab data to determine the: Question options: soil's parent material. soil's structure. soil texture. soil color.

soil texture (1) Sand - largest particle size; essentially what you find in a sandbox or on a Lake Michigan beach; feels gritty (2) Silt - medium-sized particles; feels like flour (3) Clay - smallest particle size; feels smooth and slippery; soil nutrients are usually attached to the outside of these particles, so soil fertility is related to clay content

Parent material

the original, largely mineral, material in which a soil forms.

Solum

the uppermost set of soil horizons (for example, a soil's A and B horizons).

Most soil-forming factors actively influence soils development, except for ______, which is passive.

time

Calcium in the E horizon dissolves in rainwater and is deposited in the B horizon. This is an example of: Question options: soil depletion. translocation. soil addition. transformation

translocation (pg. 268)