Soils Exam 1

Geophagy

Deliberate eating the soil

A soil developed in transported parent materials will likely have properties related to the properties of the rock below the C horizon.

False

Alluvial parent materials are those that have been laid down in former lake bottoms.

False

Although subsoil is more difficult to obtain, it is generally equally as good as topsoil for landscaping purposes.

False

Except for some kinds of foods, modern industry has made human dependence on soils a thing of the past.

False

Glacial till is laid down by melt waters gushing out from the front of glaciers.

False

Soils developed in wind-blown parent materials such as loess are generally of little agricultural value.

False

Subsoil is typically equivalent to the O horizon.

False

The C horizons are generally more completely weathered than the other horizons.

False

The topmost horizon in most humid region forest soils is the A horizon.

False

Where organic matter constitutes only 1 or 2 percent of the soil by weight, it has only negligible influence on soil properties.

False

While many organisms depend on the soil for nutrients and water, only a few very specialized organisms live in the soil itself.

False

Horizon A

surface mineral horizon; lots of organic matter mixed with

Exfoliation is caused by changes in _________.

temperature

The amount of different sizes of mineral particles in a soil defines the soil ________.

texture

Horizon B

illuviation that has collected from the E horizon

Inceptisol

weakly developed, no clay accumulation

Which of the following is (are) essential plant nutrients?

Cu

layer of soil profile

Horizon

the relative proportions of the various soil separate in a soil

Soil Texture

Which of the following pH values represents the most acid condition?

1.0

A soil

3d natural body

In a load of 10 cubic meters of topsoil, approximately how many cubic meters of the volume would be solid material?

5

In a typical mineral soil in optimal condition for plant growth, approximately what percentage of the pore space would be filled with water and what percentage filled with air?

50% water and 50% air

Hydroxyl ion concentrations are greatest in a soil solution with a pH value of ______.

6.5

Which of the following pH values represents a neutral condition?

7.0

"Topsoil" is generally equivalent to which soil horizon?

A

In a given soil, the horizon with the highest organic matter content is generally the _____ horizon.

A

Discuss how a soil, a natural body, differs from soil, a material that is used in building of roadbed?

A soil is an organized, three dimensional body that is a component of a landscape. Mere soil is some material from such a body that can be moved around by a shovel or bulldozer

The water in the soil typically differs from pure water because the soil water ________.

A. contains organic compounds B. contains mineral nutrients C. is restrained in its flow by attraction to particle surfaces

Igneous rocks can best be characterized as:

A. rocks formed when molten magma solidifies

Use the key given in Figure 3.11 to determine the soil order of a soil with the following characteristics: a spodic horizon at 30 cm depth, permafrost at 80 cm depth. Explain your choice of soil order

Always begin at the top of the key. The presence of permafrost causes the soil to key out as a Gelisol. Only a "no" answer for the first two queries would allow the spodic horizon to come into play in keying out a Spodosol.

"Subsoil" is generally equivalent to which soil horizon?

B

In which of the following horizons has the process of illuviation most likely occurred?

B horizon

Increasing the organic matter content of a soil is likely to _____.

B. increase the soil's water holding capacity

Residual parent materials are best described as __________.

B. materials formed by weathering of rocks and minerals in place.

Compared to silt, clay-sized soil particles are characterized by ______.

C. greater attraction for water

organic and inorganic matter with very small particle size and a corresponding large surface area

Colloidal

the science that deals with influence of soils on living things particularly plants, including human use of land for plant growth.

Edaphology

Rearrange the following soil orders from the least to the most highly weathered: Oxisols, Alfisols, Mollisols, Entisols, and Inceptisols

Entisols (least); Inceptisols; Mollisols; Alfisols; Oxisols (most weathered)

Weathering of rocks usually is most intense in the center of a rock fragment, and gradually decreases toward the outside.

False

Andisol

Formed in volcanic material's has specific material properties related to density, phosphorus, and water holding

the more or less stable fraction of the soil organic matter remaining after the major portions of added plant and animal residues have been decomposed, usually dark in color.

Humus

water removed from first plant, hold water least tightly replaced with air

Macropore

Functions of soils in our ecosystems:

Medium for plant growth Regulator of water supplies Recycler of raw materials Atmosphere modifier Habitat for soil microorganisms Engineering medium

water held tightly, not always available to plant when here, generally filled with water rather than with air

Micropore

Which of the following is considered to be a plant macronutrient?

N, P, S, Ca

Are all elements contained in plants essential nutrients? Explain.

No, plants also take up elements which are not essential to the plant's growth. Examples are silica and sodium (not essential for some plants), selenium, vanadium, lead, etc. Some of these are nutrients for animals eating the plants, others (such as lead) are not, but are of concern because of their potential for animal toxicity

Organic matter accumulation is most pronounced in the ____.

O horizon

soils

One of the individual soil bodies

the unconsolidated and more or less chemically weathered mineral or organic material from which the solum of soils is developed by pedogenic processes

Parent Material

Compare the pedological and edaphological approaches to the study of soils. Which is more closely aligned with geology and which with ecology?

Pedologists study soils as natural bodies in the landscape without a particular land use in mind. Pedology is therefore closely related to surficial geology. The edapthological approach to soils aims at understanding the soil system as it relates to the suitability of the soil as a medium for plant growth. Edaphology is therefore a kind of ecology

the science that deals with formation morphology, and classification of soul bodies as landscape components.

Pedology

What does the soil provide for the plant?

Physical support Air Water Temperature moderation Protection from toxins

List the essential nutrient elements that plants derive mainly from the soil.

Plants derive these essential (or quasi-essential) elements mainly from the soil: N, P, K, S, Ca, Mg, Si, Na, Fe, Mn, B, Zn, Cu, Cl, Co, Mo, Ni

the unconsolidated mantle of weathered rock and soil material on the Earth's surface; loose earth materials above solid rock.

Regolith

the capacity of a soil to return in its original state after a disturbance

Resilience

a layer of soil, approximately parallel to the soil surface, differing in properties and characteristics from adjacent layers below or above it.

Soil Horizon

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

Soil Profile

vertical section of the soil through all its horizons and extending into parent material

Soil Profile

the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation

Soil Quality

the combination or arrangement of primary soil particles into secondary soil particles into secondary soil particles, units, or peds

Soil Structure

Explain why Soil Taxonomy is said to be a hierarchical classification system.

Soil Taxonomy is hierarchical because at each level, several taxa are group together within a higher level category, e.g. several great groups are included in each suborder and several suborders, in turn, are included in each order.

the negative logarithm of the hydrogen ion activity of the soil

Soil pH

Soils in this order are commonly sandy in texture, quite acidic and develop primarily under coniferous trees in cool to cold climates

Spodosols

Below the layer B horizon; deeper layer that stores water for later usage; not as good as topsoil for plant growth

Subsoil

The configuration of the land surface described in terms of elevation, slopes, and landscape position, the lay of the land

Topography

a horizon located; gets moved around with cultivation; fertile layer of soil; referred to as cultivated soil

Topsoil

Hydrolysis involves the splitting of water into its H+ and OH- components while hydration attaches intact water molecules to a compound.

True

Igneous rocks are formed when molten magma cools and solidifies.

True

Most of the water in our rivers and lakes has come in contact with and has been affected by soils.

True

Organic deposits are most common in areas where water flow over the soil surface is restricted.

True

Plants can be grown without any soil

True

Residual parent materials have formed in place and have not been transported from one area to another.

True

Secondary minerals are recrystallized products of the chemical breakdown and/or alteration of primary minerals.

True

Soil air usually has a higher carbon dioxide content than the air in the atmosphere.

True

The A horizons are more apt to be cultivated than the E horizons.

True

The O horizons of a soil are dominantly organic horizons occurring above mineral horizons.

True

The mineral particles in soil consist of sand, silt, and clay.

True

What is the principal soil property by which Ultisols differ from Alfisols? Inceptisols from Entisols?

Ultisols have a lower percentage base saturation (<35%) deep in the profile than do Alfisols. Inceptisols have some kind of easily developed B horizon while Entisols have no B horizon.

Of the five soil-forming factors discussed in Chapter 2 (parent material, climate, organisms, topography, and time), choose two that have had the dominant influence on developing soil properties characterizing each of the following soil orders: Vertisols, Mollisols, Spodosols, and Oxisols.

Vertisols: parent material, climate (dry season) Mollisols: organisms (grass vegetation), parent material (high calcium) Spodosols: climate (humid, high effective precipitation); parent material (sand or sand-forming) Oxisols: climate (hot, humid), time (very old)

Soil

a dynamic body on the surface of the earth in which plants grow and is comprised of air, water, minerals, and organic matter interacting with living organisms and is a product of climate and vegetation acting on a parent material in a specific location over time.

A soil pedon is ____

a three-dimensional unit that embodies the primary characteristics of an individual soil

As a society, is our reliance on soils likely to increase or decrease in the decades ahead? Explain.

a. Need to transform solar energy into food energy over huge areas of the Earth's surface. b. -Society's increased appreciation of and continued dependency on the services of natural soil-based ecosystems for water, wildlife, natural cycles and recreation. c. - Increasing replacement of petroleum by soil-grown plant products as feedstocks for chemical industry (e.g. soy bean based inks). . d. - Increasing replacement of finite fossil fuels with renewable plant-based biofuels (e.g. ethanol).

What are the six main roles of soil in an ecosystem? For each of these ecological roles, suggest one way in which interactions occur with another of the five roles.

a. Six soil roles or functions: i. (1) medium for plant growth; ii. (2) regulator of water supplies; iii. (3) recycler of nutrients and carbon; iv. (4) modifier of the atmosphere; v. (5) habitat for soil organisms; vi. (6) engineering medium. b. Examples of interactions between these roles: Plant cover (medium for plant growth) enhances infiltration of rainwater (regulator of water supplies); an abundance of soil organisms (habitat for soil organisms) enhances the release of nutrients (recycler of nutrients) by the decay of plant residues.

Describe four processes that commonly lead to degradation of soil quality.

a. Some soil degrading processes: erosion, salt accumulation (salinization), nutrient depletion, and chemical pollution.

Spodosol

acid, sandy, forest soils; highly leached; cold regions; coarse texture feel, highly acidic; not very put together

Utisol

argilic horizon, highly weathered and leached, developed under forests in humid topics and subtropics

Horizon R

bedrock; parent material

`the composite or generally prevailing weather conditions a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds throughout the year, averaged over a series ofyears

climate

The soil

collection of individually different soil bodies

Mollisol

dark, soft soils, associated with grasslands: worlds productive soils, great plains over the US is made up of

Verisol

dark, swelling, and cracking clay

Aridisol

dry soils; prominent in the west parts of the U.S. can be productive if managed and fertilized

the water that moves through the regolith and is largely available for plant growth

effective precipitation

Which of the categories in the Soil Taxonomy system indicates properties that have implications for root growth as well as for the construction of building foundations?

family

Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties?

family

Sedimentary Rock

form when weathering products released from older rocks collect under water as sediment and eventually reconsolidate into a new rock; most common

Igneous Rock

formed form molten magma

Metamorphic Rock

formed from other rocks by a process of change call metamorphism

The mixed angular gravel, rock, and soil found at the foot of a slope is typical of what type of parent material?

glacial

Gelisols

has permafors

The layers of contrasting material found when one digs a hole in the ground are called _______.

horizons

Horizon O

illuviation

Horizon C

minimally weathered; just becoming soil it lacks characteristics of other horizons

Alfisol

moderate leached; broad leafed forests and savannas

Oxisol

most highly weathered of the soil orders, rainforest, tropical areas like Hawaii

Histosol

organic soils without permafrost, peat moss

the smallest volume that can be called soil

pedon

two or more contigugous pedons all of which are within the defined limits if a single soil series, commonly referred to as a soil individual

polypedon

Most of the different nutrients essential for growth are supplied to plants directly from the ______.

rain water

Entisol

relatively undeveloped

Essential nutrients

required to finish life cycle

The lithosphere is made up of _________.

rock

A soil profile consists of _________.

soil feels

Nonessential nutrients

things that the plant takes up and doesn't need to grow.

Igneous, sedimentary, and metamorphic are three _________.

types of rock

Soil occupies the ______part of the regolith.

upper

Which of the following is not considered one of the five major factors influencing soil formation?

valence state

Horizon E

washed out, missing a lot of characteristics

all physical and chemical changes produced in rocks, at or near the earth's surface by atmospheric agents

weathering

Glacial till is a term used to describe parent materials that:

were transported by water gushing from glacial fronts.