GY 102 Learnsmart Chapter 16
Select materials commonly found above the topsoil. (Choose all that apply.)
Leaves; Branches
Match each soil problem with the type of soil it is associated with or with its environmental condition.
Liquefaction: Loose sediments saturated with water create quicksand. Swelling: Clays absorb water expanding upward or sideways and shrink when moisture is low, causing problems from cracked foundations to landslides. Compaction: Clay minerals start randomly arranged and align themselves as loads such as buildings or traffic apply force; results are usually not uniform.
___ are soils formed under mid-latitude grasslands and are some of the most productive soils in the world.
Mollisols
When determining the mineral fraction of soils, which three size categories of particles are used?
Sand, Slit, Clay
Soils formed in the subtropics with a moderate level of weathering compared to other soils formed in a similar climate and leached accumulation of clays in the B horizon are called ___.
Ultisols
Match the soil horizon with the description of how it forms.
Zone of leaching (E): Results from vigorous chemical weathering that leaches iron, clays, and organics Zone of accumulation (B): Results from the accumulation of leached material from above Regolith (C): is weathered bedrock from below and is little affected by overlying processes
Soils in hot, humid environments develop more quickly than in other climates, primarily because ___ weathering occurs easily.
chemical
Oxisols, Ultisols, Vertisols, and Aridisols are soil orders formed in warm ___, with moisture levels ranging from tropical to arid and relatively warm temperatures.
climates
Directional planting of trees as windbreaks and filter strips capturing runoff sediment are types of ___ techniques for soil erosion management.
control
Poor agriculture practices, including overgrazing, deforestation, and construction projects, are all examples of human effects on the acceleration of soil ___.
erosion
Steep topography and heavy precipitation will lead to surface-water runoff and soil ___.
erosion
The detachment and subsequent movement of a soil particle from underlying material is called soil ___.
erosion
Topography impacts soil properties by influencing ___.
erosion rates
Good soils have a small amount of ___ matter, which binds soil, bonds nutrients, cycles nutrients, and provides energy for organisms.
organic
This graph represents the ___ components of soil.
organic
Heavy soils that retain too much water and do not dispense nutrients are heavy, or ___ drained soils. Soils that drain ___ and leach nutrients are droughty.
poorly; quickly
Define soil water by selecting the two descriptions below that apply.
soil water provides nutrients; soil water adheres to soil grains
Preventative techniques used to minimize the effects of soil erosion by agriculture include ___. (Select all that apply.)
strip cropping; "no till" agriculture; animal number management
The way soil particles are grouped or attached to each other in aggregates is called soil ___.
structure
The O and A horizons together are ___.
topsoil
Order the soil horizons as they would appear in a well-developed soil, with the oldest layer at the bottom and the newest at the top.
1. Accumulated clays 2. Developed soil structures 3. Weathered parent material 4. Unweathered rock
Particle sizes in soil affects permeability, where larger particles generally have higher permeabilities. Rank these soil particle types by high permeability at the top to low permeability at the bottom.
1. Gravel 2. Sand 3. Slit 4. Clay
Rank the pH of the following soils from the lowest pH (acidic) at the top to the highest pH (basic) at the bottom.
1. Humid environment soils; abundance of H+ ions 2. Agriculturally productive soils 3. Arid environment soils; shortage of H+ ions
Order the steps of soil formation caused by climate and vegetation from the first step at the top to well-developed soil at the bottom.
1. Precipitation begins disintegrating rock. 2. Organic materials facilitate disintegration. 3. Organic materials accumulate and horizons form. 4. Developed soil supports thick vegetation.
Imagine a water molecule has evaportaed from a lake. Order the steps the water molecule might take to return to the lake through the hydrologic process. (Order the first step at the top and the last at the bottom.)
1. Precipitation: the molecule is collected in clouds that eventually rain. 2. Infiltration: the rain accumulates in soil. 3. Groundwater flow: water travels through an aquifer. 4. Surface water recharge: groundwater discharges into a surface water body. 5. The molecule returns to the lake.
Order the soil practice types from largest to smallest, with the largest grains at the top and the smallest grains at the bottom.
1. Sand 2. Slit 3. Clay
Order the quantity of soil water from the most at the top to the least at the bottom.
1. Saturated 2. Field capacity 3. wilting point
Order the steps of soil formation caused by climate and vegetation from the first step at the top to well-developed soil at the bottom.
1. precipitation begins 2. organic materials facilitate disintegration 3. organic materials accumulate and horizons form 4. developed soil supports thick vegetation
Recall the average porosities for clay-rich and sandy soils by matching the soil to its porosity.
35-40% porosity: sandy soils >50% porosity: Clay-rich soils
Which of the following soils is likely to be the most fertile?
A dark brown soil
___ are very productive soils with a significant accumulation of organic matter in the A horizon. The soils tend to be acidic and are located in mid-latitude forests.
Alfisols
Select materials commonly found above the topsoil. (Choose all that apply.)
Branches; Leaves
Water available in soils is critical to plants, but capillary soil water is perhaps the most important for agriculture. Why?
Capillary water is available for a longer duration than precipitation.
What process allows high pH soils to have a strong ability to exchange cations in soil solution with the organic material surfaces or clay particles?
Cation exchange capacity
The acronym ClORPT is used to list factors of soil development. Match the specific letters to the factors they represent.
Cl: Climate O: Organic matter/vegetation R: Relief/topography P: Parent material T: Time
Match the soil to the level of CEC (cation exchange capacity) it might normally have.
Clay-rich: High CEC Sandy: Little to no CEC
Match the name of the transported parent material with its description.
Colluvium: Deposits at the bottom of slopes Glacial deposits: Deposits where glaciers have been Aeolian deposits: Wind-blown deposits Alluvium deposits: Stream-deposited sediments
Agriculture is most commonly thought of as the primary use for soil; however, humans use soil for many different purposes. Which of the following are other uses for soil? (Select all that apply.)
Construction, Purifying drinking water, Remediating pollution
Match the chemical process of soil formation to its description.
Eluviation: Easily dissolved materials such as nutrients and other fine particles are leached downward by infiltrating water. Accumulation: Chemical ions leached from above layers collect in deeper zones if they do not reach the water table.
Compare the difference between elevation and illuviation of soils.
Eluviation: Leaching of clays from surface horizons due to high rainfall Illuviation: Deposition of clays in lower levels of soil
___ are recently created soils with little to no profile development.
Entisols
True or false: Soils derived from parent materials are consistent across the globe if derived from similar parent materials.
False
Match the ped shape description with the soil structure types.
Granular: Small spherical grains Blocky: Irregular chunks Platy: Horizontal plates Columnar: Fragments that are taller than they are wide Structureless: Loose singular grains Massive: No obvious structure
___ are newly formed soils that have the beginning of a B horizon and show mild weathering. They are widely distributed across the globe, except in Australia.
Inceptisols
Select the reasons why soils in arid environments have limited development. (Choose all that apply.)
Lack of vegetation, Lack of rainfall
Select the processes that improve the organic content of soil. (Choose all that apply.)
Litter accumulation, such as dead leaves; Organisms aerating, mixing, and fertilizing soils; Decomposition of organisms; Fracturing of soils from roots
Match the topography with the kind of soil that typically forms on it.
Mountain peak: Bare rock or parent material; extreme erosion Hill: Some organic material and soil development; some erosion Flat meadow: Adequate organic material, deep soil development; little erosion
___ are soils formed in wet, tropical, hot environments, especially near the equator. The soils are heavily weathered, experience heavy leaching, and are high in oxidized iron and aluminum with low nutrients levels.
Oxisols
___ is a materials ability to transmit a fluid.
Permeability
From the list of elements below, select the three that are usually primary ingedients of fertilizers for increasing soil productivity.
Potassium(K), Nitrogen(N), Phosphorus(P)
Select ways water enters soil. (Choose all that apply.)
Precipitation, Infiltration
___ erosion techniques minimize the impact of rain splash erosion and runoff.
Preventative
Match the correct definition of primary and secondary minerals in soils.
Primary minerals: Come directly from the weathering of other minerals; may change in size. Secondary minerals: Undergo chemical weathering to form new minerals.
Identify some of the advantages organic content provides for soil health. (Choose all that apply.)
Reduced erosion; Water retention; Nutrient cycling
Match the parent material to the type of soil it will produce.
Sandstone: Sandy loams and loamy sands Shale: Clay-rich soils Limestone: Highly productive soils
Match the type or stage of soil erosion with the conditions of water flow and soil surface.
Sheet erosion: Rainfall runs on the surface in a flat sheet, carrying a thin layer of soil with it. Rills: Erosion is channeled into shallow channels 2-4cm deep. Guilles: Erosion is now channeled into an area more than 4cm deep. Steambed: Erosion is now in an advanced stage where a large area, several feet wide or deep, has formed to channel storm water flow.
Soil is the interface between each of Earth's spheres. Match the four soil components with the corresponding sphere interfaces.
Soil moisture: Lithosphere-hydrosphere Organic material: Lithosphere-biosphere Air: Lithosphere-atmosphere Minerals: Lithosphere-lithosphere
Summarize soil distribution patterns in North America using the items below. (Select all that apply.)
Soil types are similar in areas of similar land use; Soils types are distributed along latitudes; Soil types are similar in areas of similar climate.
What processes or physical properties should be considered when analyzing soils or the parent materials they formed from? (Select all that apply.)
Soils are dependent on climate during the weathering of parent material; Soils may require additions or amendments such as humans to be productive
What processes or physical properties should be considered when analyzing soils or the parent materials they formed from (Select all that apply.)
Soils are dependent on climate during the weathering of parent material; Soils may require additions or amendments such as humus to be productive
What are the effects of soil erosion? (Choose all that apply.)
Spreading of bacteria and viruses, Loss of agricultural productivity, Filling in of reservoirs
What are the effects of soil erosion? (Choose all that apply.)
Spreading of bacteria and viruses; Loss of agricultural productivity; Filling in of reservoirs
Recognize the descriptions of temperate soils by choosing all that apply.
Temperate soils have cooler temperatures than tropical soils; Temperate soils have more mobile nutrients than arid soils; Temperate soils have nutrients available in the root zone of plants
Recognize the descriptions of temperate soils by choosing all that apply.
Temperate soils have more mobile nutrients than arid soils; Temperate soils have nutrients available in the root zone of plants; Temperate soils have cooler temperatures than tropical soils
Why is the pH of a soil important to its productivity?
The correct pH allows soil to carry the right amount and types of nutrients and makes them available to plants.
Why is the pH of a soil important to its productivity?
The correct pH allows soil to carry the right amount of nutrients and makes them available to plants.
Choose a descriptor about the soil sample on the left to compare the soils in this image.
The soil contains organic material.
Identify some of the advantages organic content provides for soil health. (Choose all that apply.)
Water reduction; Reduced erosion; Nutrient cycling
What is regolith?
Weathered parent material
When studying the saturation and oxygen conditions of soil formation, brightly colored soils generally indicate well aerated conditions, and dull, gray soils indicate ___ conditions.
anaerobic
Areas where soil develops slowly, with little rainfall, little vegetation, limited nutrient availability, and calcium carbonate accumulations are ___ environments.
arid
Gelisols are soils on top of permafrost and are often waterlogged. They are found ___.
at high elevations or high latitudes
When salt accumulates in arid soils, the salts coat grains and form a layer called ___.
caliche
An acidic soil contains a high number of H+ ions, and ions such as Mg+, K+, and CA2+, known as ___, will be repelled.
cations
Control techniques used to minimize effects of soil erosion in agriculture are ___. (Select all that apply.)
directional planting of wind breaks; plants acting as sediment fillers
Soil ___ patterns are found along latitudes, in areas of similar climate, and in areas of similar land use.
distribution
Soil ___ patterns are found along latitudes, in areas of similar climates, and in areas of similar land use.
distribution
Soil color is an indicator how a soil formed and is linked to the ___. (Choose all that apply.)
history of vegetation growth; history of soil saturation; minerals contained in the soil
Soil controls pollution by ___. (Select all that apply.)
holding containments long enough for organisms to detoxify or immobilize them; binding contaminants with minerals in soils with a neutral pH
Soil controls pollution by ___. (Select all that apply.)
holding contaminants long enough for organisms to detoxify or immobilize them; binding contaminants with minerals in soils with a neutral pH.
As soil forms through weathering and the accumulation of organic matter, layers called ___ are created over time.
horizons
Soil profiles are composed of vertical sections of soil called ___ that extend from the surface to the parent material.
horizons
A soil that has been compacted so that its permeability is extremely low is called ___.
impermeable
Aridisols are soils with very little organic matter, limited leaching, which forms accumulated layers of nutrients, and limited weathering and soil layer development. They are found ___.
in arid environments
Spodosols are not very productive soils because they form under acidic forest litter (white-gray leaching) and have short growing seasons. They are found ___.
in coniferous forests of the Northern Hemisphere
Mollisols are the most agriculturally productive soils. They are found ___.
in mid-latitude grasslands
Vertisols are clay-rich soils with swelling and shrinking tendencies, resulting in poor soil structure and poor profile layers. They are found in ___ environments.
in temperate and subtropical
Soil horizons are ___.
layers in the soil from distinct periods of development
Above topsoil is the ___ layer, composed of loose twigs, branches, leaves, and the like.
litter
Soils described as ___ have a texture that is good for agriculture compared to sands that drain water and nutrients or clays that drain poorly or become compacted.
loams
A soil with a wide range of grain sizes (poor sorted) will have ___ porosity compared to one where the particles are all nearly the same size.
low
Humus is the stable, partially decomposed form of ___ found in soil.
organic matter
Soil is derived from ___ material, such as rocks.
parent
What is the name for the partly decayed plant material that accumulates in marshes and bogs?
peat
The smallest unit used to measure soils is called a(n) ___, which measures 2 meters deep and 1 to 10 meters square.
pedon
The weathering of bedrock and deposition of sediment by wind or water are ___ processes involved in soil formation.
physical
Given a soil with a volume of 100cm^3 and a pore space of 40cm^3, the ___ is 40%.
porosity
Managing the number of animals grazing, using "no till" agriculture practices, and strip cropping are ___ techniques for soil erosion management.
preventative
The main causes of the detachment necessary for soil erosion are ___ and ___.
rainsplash, freeze-thaw cycles
Soils from tropical regions get their ___ color from the oxidation of iron and aluminum, a form of natural rust.
red
This is the name for weathered parent material.
regolith
The three primary taxonomies of soil are ___-dominated soils, developing soils, and soils with strong ___ influence.
site; climatic
Binding pollutants to minerals and limiting surface pollutant infiltration into groundwater systems are all methods by which ___ controls pollution.
soil
Organic matter in ___ accumulates through contributions by living organisms.
soil
Ultisols are moderately weathered soils with clay mineral deposits in the B horizon. They are found in ___, similar to Alfisols and Oxisols.
subtropical forests and savannahs
Temperate environments have some of the best soils in the world, when compared to tropical soils. The reason is ___.
temperate soils have less rainfall to leach nutrients
Soil ___ is a physical property of soil that describes the average distribution of particle sizes.
texture
Soil near the surface with an abundance of humus, living organisms, and some inorganic minerals is called ___ and is the primary nutrient source for plants.
topsoil
Forensics, athletic fields, and ___ are some of the more unconventional uses of soil.
use in modern medicine
Andisols are soils that are rich in nutrients that are formed from weathered parent material. They have good moisture capacity and are a product of ___.
volcanic ash and ejecta
A critical liquid ingredient in soils determines if vegetation can grow is ___. The quantity of this ingredient in soil is dependent on climate, soil texture, and structure.
water
Anthropogenic (human) uses of soil range dramatically from agricultural production to construction foundations and from pollution remediation to purifying the drinking ___ supply.
water
Aridisols's sparse organic matter and leached nutrients are different from other soils formed in the tropics and subtropics (e.g., Oxisols, Ultisols, and Vertisols) because of Aridisols's lack of ___ and vegetation.
water
Soil air content is proportional to soil ___ content, which are both dependent on pore space.
water
Soil development in tropical (humid) environments tends to be faster than soil development in arid environments (both warm or cold), due to the availability of ___.
water
Soil is a critical resource because it provides humans with ___. (Select all that apply.)
water recycling; food and clothing
The physical primary mechanism for soil formation is ___.
weathering and loosening of bedrock
Soil erosion in the United States tends to come in two types: ___ erosion in the High Plains or Great Plains areas of the central U.S., and ___ erosion in the Midwest.
wind; water
