soils exam Final (cox)

At what Ph range does Al^3+ start becoming available to affect soil processes

5.2-5.5

In what range of soil PH is phosphorus generally most available to plants

5.5 -7.0

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 with air

50% water and 50% Air

3 mole of Al^3+ contains how many moles of positive charge?

9

"Topsoil" is generally equivalent to which soil horizon

A

In a given soil, the mineral horizon whith highest organic matter content is generally the ______ horizon

A

Which of the following are true?

A mature soil does not need to have all of there mater horizons to be considered as oil.

Two soil samples A and B at different soil moisture levels are placed in contact with each other. Water will more likely move from soil A to soil B if their water potentials, expressed In Kpa are

A=+;B=-5

The B horizon can be high in

All of the Above

Living organisms can affect the soil profile through

All of the above.

The water in the soil typically differs from pure water because the soil water:

All of these

"subsoil" is generally equivalent to which soil horizon

B

In which of the following horizons has the process of illation most likely occurred

B horizon

silicate clay accumulation is most common in the

B horizon

Organic Matter additions to a soil can decrease

Db

which of the following irrigation systems produces the most biomass per unit of water applied ?

Drip irrigation

Mississippi has glacial parent material in the form of

Eolian loess

epipedons are diagnostic subsurface horizons that are one of the primary means of classifying soils in the United States

False

Soil A has a profile with a lot of yellow and red colors while soil B has a predominately gray profile. Of the two soils, Soil A is more apt to be characterized by an abundance of

Fe^3 IONS

compared to silt, clay sized soil particles are characterized by:

Greater attraction for water

Which of the following statements is correct?

LAcutrine parent material have been subject to weathering for shorter periods of time than residual parent materials nearby.

you find that the CEC of a sandy loam soil at PH 5.0 is 8cmpl/ckg and at PH *.2 it is 14cmol./kg. What is the most likely reason for this difference

Loss of H+ from carboxyl and phenolic groups in the oxides and organic matter

Dull gray colors are characterized by

Low chromes

water storage in the soil is due to

Matric potential

An a horizon with a sharp, distant boundary at about 6 inches due to cultivation would most likely have. which subordinate distinction

P

Two problems associated with this particular issue are poor seedling emergence rates and high runoff rates. what is the problem?

Soil crusting

Which of the following disintegration (physical breakdown) processes has the largest effects on rocks

Temperature

mechanical weathering processes results in:

The disintegration of rocks due to differential expansion of minerals.

The swelling/shrinking tendency of some silicate clay minerals is due primarily to_____.

The movement of water molecules in and out of the interlayers of the crystal.

You are consulting a farmer about there plans for the next few years. You have web soil survey open and notice that one of the fields has a Bg horizon 12" depth with a prodominelty gray background. from this information, you conclude which of the following

The soil is poorly drained the crops to be grown should be chosen carefully.

We must use our soils wisely and protect them because

They are reuseable,but not renewable recourse

The four soil formations process are

Translocation,transformation, addtitions and losses

Organic matter distribution in the profile is significant criterion for differentiating eppipdeons

True

The broadest category of classification in soil taxonomy specifies 12 soil orders, 11 of which are for mineral soils.

True

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

True

evaporation from the soil surface (e) is determined to a large degree by soil surface wetness

True

A subsoil that has both a "g" and a "t" subordinate distinction (btg) can be expected to have

a clay accumulation and grey colors

soil quality is a term used to describe the soils

ability to carry out ecological functions

Argillic horizons are characterized by

accumulation of silicate clays

when measuring Ph with a PH meter, which pool of soil acicdiy are we measuring.

active

An important part of the definition of soil is that it is

all of the above

Which of the following will decrease the evaporation (E) from the soil surface

all of the above

which of the following practices is (are) useful in stabilizing the surface soil structure

all of the answers

colluvial parent material

along the slides slope and toe slope of a landscape

The presence of rocks such as shale and sandstone indicate the existence of

ancient seas

soil structure describes the____ of particles in a soil

arrangment

surface ditches are an effective way to remove large volumes of water

before it enters the soil

Practices that decrease organic matter and increase tillage can be expected to most significantly increase the _____ in the soil

bulk density

in soils of which great group would you most likely find wide surface cracks during periods of dry weather

calciusterts

Humus is an important soil colloid. It is like 2:1 type minerals in which one of the following characteristics

capable of adsorbing cation

secondary minerals are most important in the _______ fraction of soils

clay

secondary minerals are most prominent in the ______ fraction of soils

clay

Decreasing the organic matter content of a soil is likely to

decreases the soils structure . (disperse in the soil aggregates)

If you wanted to find a soil where physical weathering is dominated over chemical breakdown you would be most apt to find it in

desert region of Arizona

erosion process consist of three steps: Detachment,transport, and deposition. to control water erosion, we must devise methods to stop what?

detactchment of the silt fraction from the soil aggregates

soil crusting is due to aggregate

dispersion

A watermelon grower asked you for your recommendation on an irrigation method. Based on your experience which of the following methods would you recommend. (watermelons don't like wet soils and are a high value crop)

drip irrigation

which of the following is not a characteristic of most soil colloids

electropositive charges

A tetrahedral sheet is characterized by a plane of aluminum atoms surrounded by oxygen and hydroxyl groups.

false

A,B<c and E horizons can be found in any true soil.

false

Although subsoil is more difficult to obtain, it generally equals 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

The categories of soil taxonomy can be listed from the broadest (first) and most specific (last) as : order, suborder,greatgroup,subgroup, series family.

false

isomorphic substitution involves the substitution of a tetrahedral sheet for an octahedral sheet

false

polsaccharides produced by soil microbes and similar synthetic polymers applied to soils are largely responsible for the crust that forms when rain follows tillage

false

sandstones are good examples of metamorphic rocks

false

soil, like concrete and steel is a standard conturcution material. its properties are well characterized and predictable so that standard building foundation designs can be used uniformly at all building sites of a given topography

false

subsoil is typically equivalent to the o horizon

false

while 2:1 type clays have significant internal surfaces, their external surfaces are generally much more extensive.

false

soils classified as inceptisols have the least well developed profiles of those in any order in the taxonomy system.

false.

which of the following categories of soil Taxonomy provides the greatest specificity of soil properties

family

some cations are important in rememditating soil crusting problems because they

help to flocculate the soil colloids

soil derived from eolian parent materials ten to be

highly erodible

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

horizons

In a soil at PH 5.0 most of the inorganic P is likely ti be in the form of

hydrous iron and aluminum phosphates

Muscovite mica is an example of a

igneous rock

Increaing the organic matter content of a soil is likely to

increase the soils water holding capacity

capillary in soils

involves both adhesion and cohesion

The element most often involved in oxidation reactions as minerals weather is

iron

The matric potential of soil water

is not influenced by the force of gravity.

The negative charges associated with vermiculite clay crystals are do mostly to

isomorphic substitution of Mg for Al in the octahedral sheets

The electronegative charge on 2:1 type silicate clays is due primarily

isomorphic substitution of one metallic atom for another in the crystal structure of the clay.

Why is AL^3 considers to be an acid cation

it hydrolyzes water and release H+ into the soil solution

As the clay content and /or the organic matter content increases in a. soil. What happens to the buffering ability of the soil.

it increases

subsurface land drainage is beneficial because

it increases the depth of root penetration in the soil.

Given the family: Fine -sandy, smectic mesic Aquaic Haplaudalf what do you know about this soil

its likely formed under a forest.

An ultisol can look like a mollisol or alfisol but it is different in that it has a

low base saturation

you are working with a soil colloid known to have a cation exchange capacity of about 100 cool/c Kg of clay and a high tendency to swell when wetted. which of the following is it most apt to be the dominant clay mineral in this soil?

monmorillinite

If you were seeking a soil colloid with a high capacity to adsorb cationic pollutants, but also with a consistent capacity to do so even as Ph varied form 4.0 to 7.5 which of the following would choose.

montmorillonite

what happens to perminate charge as the PH of the soil increases

nothing

organic matter accumulation is most pronounced in the

o horizon

Additons to the soil primarily affect the soil profile through

organic matter

which of the following is not a secondary mineral?

plagioclase feldspar

of the various types of drain systems open sitch system re most practical and economical for use on _____.

poorly drained soils with sandy profiles.

septic systems are designed to _____ household waste.

remove and treat

how does the amount of lime needed to neutralize the residual acidity in a clay loam soil compare to that needed to neutralize the active acidity in that soil.

residual requires a lot more

Ignenous rocks can be best characterized as

rocks formed when molten magma solidifies

In the soil-plant-Air continuum, once the water impacts the soil, it can either infiltrate into the profile or

runoff

A soil with a gritty feeling likely has a high percentage of which soil separate

sand

which of the following is not a textural class name?

sandy silt

As you move away from a river or a stream the soils tend to change from_____ in texture

sandy to sility to clayey

The map unites on a detailed soil map in a county soil survey report (same as Web soil survey) are most likely to be tabled with names from t=which category of soil taxonomy

series

using the Feel method, a soil creates a medium ribbon when pinched between the thumb and a forefinger. The ribbon is particularly smooth. What is the most likely soil texture

silty clay loam

A septic system needs soil to allow the waste water to move ____ enough to filter impurities

slowly

soils rich in which type of clay would not provide the best site on which to build a home.

smectite

The hydrologic cycle is the cycling of water from the atmosphere to ___. and then from the soil to either surface water or groundwater , and then to the oceans and back to the atmosphere

soil

The expression,P-ET-DV estimates the ______ a watershed.

soil water content of

some soil colloids exhibit negative charges under any PH conditions. To what are these charges likely due?

substitution of lower talent atoms for higher valent atoms in the octahedral sheets.

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

texture

Aluvial fans are most likely found where

the edges of cliffs, mountains, or bluffs where channelized water slows.

The process of soil formation is a complex interaction of

the four soil forming processes and five soil forming factors.

The soil profile consist of

the set of layers seen in a vertical cross section of a soil.

If you dug a deep hole in your back yard and water started to seep into the hole it would fill the hole up._____

the water table.

A polypedon or infdivudla soil is a group of closely related peons that conceptually approximate what in the United States is called soils series.

true

All of our lime sources use the same basic mechanics to neutralize soil acidity (Co3 or )H to consume H+)

true

HYdrolisis 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

Isomorphous substitution involves the substitution of one ion for another based on size.

true

Mollisols are found mostly near areas of natural nature or rangland

true

Soil and crop management generally has a greater influence on evaporation from the soil surface (E) than on transpiration (t) from leaf surfaces

true

The cation exchange capacity of humus increases if PH Increase

true

The two most significant characteristics of the slassfification system used in the United States are a unique system of terminology and focus on measurable soil properties as a primary basis for the classification

true

Tillage when the soil is too wet I likely to increase the soil bulk density

true

respiration is major cause of soil acidification

true

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

true

soils tend to acidify naturally

true

igenous rock, sedimentary, and metamorphic are there

types of rocks

A soil has a thick black A horizon, a distinct B horizon has a reason stable soil structure and was formed under grassland natural vegetation. in which suborder is it most likely classified

udolls

In which of the following situations would you expect downward movement of soil water through the profile to be most rapid

uniformly textured sand loam profile.

Soil occupies the ________ part of the regolith.

upper

which of the following is not considered one of the five major factors influinincing soil formation

valence state

you are preparing to buy a lot for a house. while looking over some land you take a few minutes to dig a hole and check for the presence of slickensides. The slickensides idicate the presence of a ____ which would not be good place to build.

vertisol

which of the following best characterizes the field capacity of a soil.

water content of a soil with water potential of about -0.2 to about -0.3 bar

what drives the soil-plant-Air continuum

water potential

A soil with grey mottling occurring at >30" belongs to which drainage class

well drained