soils midterm

which of the following is (are) essential plant nutrients

Cu

Colloidal properties are exhibited by the ___ fraction of soils.

clay

Most (usually 80% or more) of soil potassium and calcium can be found in the form of _________________.

structural components of minerals

Typical well drained, well developed soil in Northeast Tennessee will most likely be classified as a:

ultisol

Which of the following is not a textural class name?

sandy silt

Igneous, sedimentary, and metamorphic are three _________.

types of rocks

Which color would be typical of a well drained, low-organic matter sandy surface soil?

10YR5/8

Secondary minerals are most prominent in the fraction of soils.

clay

Practices that add organic matter and reduce tillage can be expected to most significantly increase the _____ in a soil.

macropores

Residual parent materials are best described as __________.

materials formed by weathering of rocks and minerals in place

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

1

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

In a field experiment you noted that 300 tons of water was transpired to produce 1 ton of corn (dry weight). If alfalfa had been grown in the same field instead of corn, which of the following would most likely have been the amount of water transpired?

500 tons

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

"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

Which of the following would you expect to have the highest leaf area index?

Alfalfa just before harvest

"Subsoil" is generally equivalent to which soil horizon?

B

Silicate clay accumulation is most common in the ____.

B horizon

The following is the reduced form of the essential element depicted

NH4+

A well aerated soil is characterized by a relative abundance of _____.

NO3- ions

Organic matter accumulation is most pronounced in the ____.

O horizon

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

P, Ca, S, N

Plant roots obtain access to soil water in which of the following ways?

Roots extend into moist soil area, Water flows to the roots by capillarity

Which of the following will not increase the efficiency of water use by plants in an irrigation system?

The use of flood irrigation for forage crops

Which of the following is not true with respect to the hydrologic cycle?

There is a net migration of some 40,000 km3 of water in clouds from the land area to the ocean areas.

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

a desert region of Arizona

Which of the following locations in the United States would have the highest evaporation (E) from the soil surface in July?

a furrow-irrigated cotton field in Arizona

A soil pedon is ____.

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

Because of their greater surface area per unit of soil mass, silt loams soils generally have a greater capacity than loamy sand soils to ___.

absorb water, absorb gases, release nutrients by mineral weathering, support bacterial growth

Argillic horizons are characterized by ___.

accumulation of silicate clays

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

adding straw mulch to the soil surface, the use of no-till culture, stubble mulch farming, plastic mulch none of the above

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

ancient seas

The process of aerobic respiration is a significant source of which of the following gases?

carbon dioxide

If a dry soil high in certain types of ____ is moistened, it is likely to swell up with enough force to crack pavements and building foundations.

clay

Which of the following sources of water have the shortest average residence time?

clouds

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

colluvial

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

contain a heterogenous mixture of mineral debris dropped by reading glaciers

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

contains organic compounds, contains mineral nutrients, is restrained in its flow by attraction to particle surfaces

Which of the following processes are most apt to encourage good soil aeration?

creation of more macropores

Urban development of land under natural vegetation or agriculture usually greatly _____ soil infiltration capacity and therefore greatly increases _______.

decreases stream bank erosion

The bulk of gaseous interchange in soils takes place by _____.

diffusion

The expression, P - ET -SS estimates the ________ a watershed.

discharge volume from

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

drip irrigation

Where high-value crops or individual ornamental shrubs are to be grown and water is expensive, the most efficient type of irrigation to use would be ______.

drip or trickle

In which soil orders would recent alluvium most likely be a common parent material?

entisols

Plant transpiration efficiency at a given location is markedly influenced by _____.

fertilization practices used, the plant species being grown

Soil order characterized by permafrost is known as:

gelisols

Which of the following means of estimating soil water levels gives a direct measurement of the water content?

gravimetric determinations

In which of the following "forms" of soil water are pesticides, excess plant nutrients and waste chemicals most apt to move through soils?

gravitational

Soils high in organic matter commonly hold more available water than comparable soils with lower organic matter levels. This is most likely due to what characteristics of the high O.M. soils

higher field capacity

If the soils are to be used for crop production, for which soil order would land drainage be most critical

histosols

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

horizons

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

increase the soil's water holding capacity

Capillarity in soils _____.

involves both adhesion and cohesion

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

iron

Brown and red colors in subsurface horizons are caused by __ in the soil.

iron oxides

The following are true characteristics of a water molecule.

it has a positive and a negative side

Land drainage is beneficial because _____.

it increases the depth of root penetration in the soil

Using a textural triangle chart, it can be determined that a soil with 45% sand and 20% clay belongs to the ___textural class.

loam

Wind blown silt sized materials is known as:

loess

Dull gray colors are characterized by _____.

low chromas

Compared to upland soils, wetland soils would be characterized by an abundance of _____.

methane

Soil A has a redox potential of 400 mV, soil B -200 mV. Of the two soils, Soil A is more apt to be characterized by an abundance of _____.

molecular oxygen

A soil has a thick black A horizon, a distinct B horizon, has reasonably stable soil structure, and was formed under grassland natural vegetation. In which suborder is it most likely classed?

mollisol

Soil colors are scientifically described by ____ color designations such as 10YR3/4.

munsell

Which of the following is not a major factor in determining the soil aeration status?

nitrogen gas

The matric potential of soil water is _____.

not influences appreciably by the force of gravity

Unsaturated water flow _____________.

occurs on soils that are at field capacity

The transformation of gneiss into mica, quartz, and feldspar crystals is an example of:

physical weathering and disintegration

If you owned a dairy farm with poorly drained clay soils in a humid temperate region which of the following would be most satisfactory from the standpoint of soil aeration and temperature?

ridge-till system

Soil scientists from which country first conceived the idea that soils were natural bodies?

russia

A landscaping contractor wants to change the texture of a silt loam soil to meet the specifications for a loam. S/he would most likely do so by adding ______ to the soil and mixing it well.

sand

Alluvial fans are usually characterized by soils.

sandy and gravelly

The most common form of on-site waste water treatment for homes not hooked up to sewer lines is the _______.

septic tank and drain field

The percentages of which soil components represent the minimum information necessary in order to determine the textural class of a soil?

silt and sand

Texture describes the ____ of particles in a soil.

sizes

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

soil solution

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

spodosols

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

texture

Mechanical weathering processes result in:

the disintegration of rocks due to differential expansion of minerals

Soil tilth refers to _____.

the physical suitability of a soil for plant growth

The likelihood of polluting groundwater with pesticides and plant nutrients is enhanced by _____.

the presence of macropores in the soil

The redox potential is a measure of _____.

the tendency of a substance to accept or donate electrons

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

uniformly textured sandy loam profile

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

use of organic mulches, use of green manure crops, growing grass sod, minimizing tillage

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

valence states

Soil order characterized by high swelling capacity clays is known as:

vertisols

Which of the following best characterizes the field capacity of a soil?

water content of a soil with water potential of about -10 kPa