Soil Science Combined Quiz Questions SP20 PDF

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Combined soil science quiz questions from past quizzes throughout the spring semester of 2020....

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Quiz 1 Agriculture, forestry and other land uses emit greenhouse gases into the atmosphere. Which percentage of the global greenhouse gas emission is from this economic sector? - 24% - 92% - 6% - 50% In a natural ecosystem, unaffected by human activity, most plant nutrients: - are removed from the ecosystem by water flow over and through the soil. - Accumulate, due to rock weathering, creating surpluses. - cycle between the plant and the soil in a closed loop. - are removed from the ecosystem by crop harvest. Almost every drop of water in rivers, streams, lakes, and aquifers travels through the soil or flows over its surface. - True - False The clay fraction of warm to tropical region soils are dominated by: - Oxide clays - Crystalline clays - Silicate clays - Amorphous clays In the context of Soil Science, an unconsolidated material is one with: - the individual minerals of the strata fused into a coherent mass. - discrete individual particles with pores in between; the sizes of which allow digging with a shovel. - its porous nature is due to cracks and fissures throughout an otherwise coherent mass. - a coherent mass in which the individual minerals are randomly dispersed throughout. Which of the following processes is not a component of the natural geologic cycle, unaffected by human activity. - geologic uplift. - geologic sediment deposition. - geologic erosion. - geologic excavation.

Which individual textural class covers the largest area of the soil texture triangle? - Silt loam - Sandy clay loam - Sandy loam - Clay Particulate organic matter in soil consists of: - the form of organic matter that darkly stains the soil. - low molecular weight organic compounds that are readily leached through the soil. - freshly deposited or decaying organic tissues with an identifiable cellular structure. - All of the above The mineral particles of the fine earth fraction are further sub-categorized into sand, silt and clay on the basis of: - whether they are crystalline or not. - the rock from which they were derived by weathering. - particle size alone. - particle mineralogy alone. Humans are accelerating erosion by: - overgrazing. - row crop agriculture. - Deforestation - All of the above Approximately what proportion of soil organic matter is classified as humus? - 10% - 70% - 50% - 30% An organic component of soil that is colloidal, gel-like and contains many carbon rings is: - Particulate organic matter - Dissolved organic matter - An oxide clay - Humus

For large areas of the US, there is a spatial correspondence between historical biomes and: - Soil series - Soil peddons - Soil phases - Soil orders Which of the following clay colloid classes does not contain silicate minerals as part of its structure? - Humus - Silicate clays - Amorphous clays - Oxide clays Between the atmosphere, terrestrial vegetation and soil which one contains the greatest quantity of carbon? - Soil - Atmosphere - Terrestrial vegetation - None of the above Since all plants require nutrients for their growth and because plant growth supports all other terrestrial life, then plant nutrients can never be an environmental hazard. - True - False Which of the following organic matter fractions is resistant to decomposition and strongly contributes to soil fertility? - Dissolved organic matter - Particulate organic matter - Litter - Humus In temperate region soils having a mellow, near neutral pH, silicate clays are found to carry: - a maximum charge of +150 cmolc/kg - both negative and positive charges, simultaneously - a net negative charge - a net positive charge

The loss of soil tilth is principally a response to: - the growth of a plant without addition of macro-nutrient fertilizers. - misuse of irrigation waters. - frequent tillage associated with continuous row crop production. - loading a soil with weight in excess to its strength. Using the soil texture triangle shown above, soil sample C contains approximately:

-

25% sand, 25% silt and 50% clay. 80% sand, 10% silt and 10% clay. 30% sand, 50% silt and 20% clay. 30% sand, 20% silt and 50% clay.

Since many chemical reactions in soils occur on particle surfaces, which fine earth fraction is considered the most reactive? - loam. - sand. - silt. - clay.

Typically, the most erodible soil mineral particles are: - clay aggregate. - silt. - sand. - rock fragments.

Within Earth's Critical Zone, Soil lies: - at the heart. - at the top. - at the bottom. - throughout the critical zone.

Which one of the following Earth Cycles warm the soil during daylight and cools the soil at nighttime? - the hydrologic cycle. the thermal energy cycle. the oxygen cycle. the geologic cycle.

Quiz 2 Approximately what proportion of soil organic matter is classified as humus? - 50% - 70% - 10% - 30% Dissolved organic matter is described as: - soil carbon from incomplete combustion of vegetation. - organic compounds that are immobile and cannot be leached through soil. - low molecular weight inorganic compounds that are readily soluble in water. - low molecular weight organic compounds that are readily soluble in water. The pores within a fine textured, clayey soil are: - predominantly micropores. - exclusively micropores. - predominantly macropores. - exclusively macropores. Soil macropores have two forms; biopores and inter-aggregate pores. Which one of the following statements is correct? -

Both biopores and inter-aggregate pores function in the rapid conveyance of water and air long distances through soil.

-

Biopores and inter-aggregate pores serve to store and transmit water short distances for water uptake by roots. Inter-aggregate pores are fewer in number but longer and more continuous than biopores. Biopores are greater in number but shorter and less continuous than inter-aggregate pores.

Under which of the following conditions is a pollutant chemical prevented from leaching through the soil? -

when the pollutant chemical is hydrophilic. when dissolved in the soil solution. when in a colloid associated state. when the soil pH is near neutral.

An acid soil has pH values greater than 8.5 and an alkaline soil has pH values less than 3.5. - True - False What is the source of the direct uptake of plant nutrients by roots? - soil organic matter - isomorphous substitution - the soil solution - Clay colloids

Dissolved within the soil solution are substances such as: -

anionic ions cationic ions

-

gasses All of the above

Prismatic structure: -

is typically found in subsoil horizons of arid and semi-arid regions.

-

is associated with sandy soil textures. usually permits very rapid water flow. is a typical feature of an organic soil.

When most of the soil solids are assembled into aggregates, the soil has: - Bearing capacity. - Clay loam. - Texture. - Structure The class of soil structure that exists as cube-like units and is typically found in well-developed subsoil horizons is called: - granular. - platy. - prismatic. - blocky

More important that the total porosity value for a soil is the dominant size of pores within a soil. - True - False The association of mineral soil particles (sand, silt and clay) together with organic matter into larger sized units results in the formation of: - chocolate turtles. - soil colloids. - soil texture. - Soil aggregates Potassium ions (K+) that are dissolved in the soil solution: - are in chemical equilibrium with potassium ions associated with colloid surfaces. - are retained by the soil colloids and not prone to leaching. - are not available for direct uptake by plant roots. - Are only associated with mineral colloids such as clay Which of the following is a key soil health management principle? - Maximize the presence of living roots. - Remove litter frequently by burning. - Maintain the same crop planting year to year so the soil can become accustomed to the plant. - Till the soil frequently.

The collection of chemical species that are dissolved in the soil solution are referred to as: -

sorbents. bases. dispersants. solutes.

If a soil sample is saturated with water, then its volume wetness value equals its: -

total porosity. residual wetness. oven dry wetness.

-

air-filled porosity.

A solute that has a large Kd value for a given soil:

-

is strongly associated with soil colloids and is prone to leaching. is strongly associated with soil colloids and is prevented from leaching. is weakly associated with soil colloids and is prone to leaching. is weakly associated with soil colloids and is prevented from leaching.

The collection of flattened, pancake-shaped aggregates arranged horizontally in the soil profile: -

is called a blocky structure. is a class of soil structure that can be formed by compaction. is called a prismatic structure. is a class of soil structure that allows rapid water flow through soil.

In acid soils the availability of some essential plant nutrient ions (eg. Ca, Mg, K) is decreased and the availability of some plant toxic ions (eg. Al) is increased. -

True False

The ratio between the amount of solute associated with soil colloids and the concentration of solute dissolved in the soil solution is called: -

the tilth index. the leaching potential of the soil. the distribution coefficient. the fixation capacity of the soil.

Alkaline soils often exhibit deficiencies of available iron. -

True False

The air-filled porosity of a soil is defined as: -

the proportion of the total soil volume that is water filled. the proportion of the total soil volume that is pore space. the total mass of air in a soil divided by the total soil mass. the proportion of the total soil volume that is air-filled.

Solutes in soil can exist in 2 possible states, either dissolved in the soil solution or associated with the soil colloids. -

True False

Which type of soil structure is typically found in the topsoil (A) horizon of larger organic matter content soils? -

sub-angular blocky. platy. granular. columnar.

Quiz 3 What is the source of the direct uptake of plant nutrients by roots? -

the soil solution. isomorphous substitution. clay colloids. soil organic matter

An acid soil has pH values greater than 8.5 and an alkaline soil has pH values less than 3.5 -

True False

Potassium ions (K+) that are dissolved in the soil solution: -

are in chemical equilibrium with potassium ions associated with colloid surfaces. are only associated with mineral colloids such as clay.

-

are retained by the soil colloids and not prone to leaching. are not available for direct uptake by plant roots

Earthworm casts have properties different from the surrounding soil in which the worm is living, including -

A lesser degree of aggregation. An enrichment of living plant roots that the earthworm selectively consumes.

-

Less nitrogen because the earthworm uses this element in its nutrition. A greater humus concentration

Compared to the rest of the soil, the rhizosphere is considered a local hot-spot of organism activity due to the release by roots of exudates. -

True False

Why do you suppose that the boreal forest has a much smaller Annelid biomass in comparison to a tropical forest -

the boreal forest is in a very cold climate. boreal forest soils are commonly thin and acidic. the boreal forest consists of coniferous vegetation All of the above

Plant root exudates: -

can contribute a greater quantity of carbon substrates to the soil in comparison to root turnover.

-

define the rhizosphere. are composed of a vast array of organic molecules. All of the other options listen.

Meso- and macrofauna contribute to organic matter decomposition primarily by: -

shredding litter to enhance microbial activity. releasing enzymes into the soil solution to decompose litter. their direct synthesis of humus. retaining their fecal pellets.

Among the microflora which group is responsible for the "earthy" smell of freshly plowed soil? -

algae actinobacteria. fungi. bacteria.

When there are large quantities of basic cations and few acidic cations associated with the soil colloids the soil pH is seen to be: -

neutral to alkaline. acidic. unaffected by the quantities of basic or acidic cations. commonly a small, less than 5.4 value.

The heterotrophic microflora of the soil consumes POM by releasing extracellular enzymes and taking up some of the resultant, low molecular weight DOM. -

True False

Reserve acidity is defined as: -

only exchangeable Al3+. the H+ and Al3+concentration in the soil solution. the presence of sources or sinks of acidity contributed by the soil colloids. Only exchangeable H+

The undisturbed ecosystem having the greatest microbial biomass is: -

tropical forest. grassland. cropland. Tundra

Anecic earthworm middens help protect the soil surface from crusting, runoff & erosion. -

True False

The microflora of the soil: -

includes bacteria, archaea, actinobacteria, fungi, and algae. includes all organisms visible to the naked eye. do not have cell walls. gain carbon and energy by engulfing smaller organisms.

Soil pH: - does not cause the deprotonation of carboxylic functional groups on humus colloids. has little effect on the chemical reactivity of all soil colloids. has a small influence on the electrostatic charge of humus colloids. has a large influence on the electrostatic charge of humus colloids.

Which of the following is the correct ordering of organisms contribution to soil biomass (where > means greater than): -

root biomass > worm biomass > microbial biomass. microbial biomass > worm biomass > root biomass. root biomass > microbial biomass > worm biomass. worm biomass > microbial biomass > root biomass.

Which group of soil organisms is considered an index of soil health because they participate at several different trophic levels? -

fungi. nematodes. bacteria. earthworms.

Which class of organisms contribute the greatest to the microbial biomass of the soil? -

actinobacteria. archaea. fungi. anecic earthworms.

Fungi tend to better tolerate acidic soil conditions, such as found in forest biomes, than bacteria. -

True False

Actinobacteria: -

contain cellular organelles such as mitochondria. are very sensitive to antibiotics such as streptomycin. contribute to organic substrate decomposition by degrading chitin and cellulose. capture and engulf food, breaking it down internally.

Quiz 4 The undisturbed ecosystem having the greatest microbial biomass is: -

tundra. tropical forest. grassland. cropland.

Plant root exudates: -

can contribute a greater quantity of carbon substrates to the soil in comparison to root turnover.

-

are composed of a vast array of organic molecules. define the rhizosphere. All of the above

The weathering of silicate clays to form oxide clays is accompanied by the loss of: -

feldspar silica. glucose. carbon dioxide

Endomycorrhizal fungi are plant pathogenic species that form arbuscules within plant cells. -

True False

The formation of unconsolidated material from rock relies on both physical disintegration and chemical alteration because physical exposure of new surfaces aids in the chemical alteration of minerals. -

True False

An example of a soil parent material formed "in place" is: -

cumulus-organic. glacial till. loess. colluvium.

Exfoliation is caused by changes in: -

oxidation. temperature. carbon dioxide dissolution. hydration.

Soils developed in loess, a parent material created by wind blown silts, are generally of little agricultural value. -

True False

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

True False

In the unglaciated regions of S.E. Ohio, where rock fragments have tumbled to the valley floor, the parent material of the soil is referred to as: -

Residuum. colluvium. alluvium. till.

Arbuscules are biologic structures that are typically formed: -

by mesofauna when they incorporate organic materials into the soil. in root cortical cells by endomycorrhizal fungi.

-

above ground by certain soil fungi. in bacterial cells when attacked by protozoa.

The fungal symbiosis with herbaceous plant species wherein the fungus penetrates root cortical cells to form arbuscules; this fungus is referred to as: -

an ectomycorrhizal fungi. a nitrogen fixing fungi. an endomycorrhizal fungi. a glomulin fungi.

The rate at which a mineral is chemically altered can depend on its composition. Therefore, all other factors being equal: -

carbonates weather faster than chlorides (as in NaCl). silicates weather faster than carbonates. silicates weather faster than chlorides. carbonates (as in CaCO3) weather faster than silicates (as in MgSiO4).

The processes involved with physical disintegration of rock into unconsolidated material includes: -

oxidation - reduction. hydrolysis. abrasion. hydration.

The author of the quiz 4 article views soil health with its focus on building soil biology as the new agricultural revolution, supplanting the green revolution and its focus on chemicals and biotechnology. -

True False

The picture below shows a common soil organism. This organism is classified as:

-

micro-fauna. meso-fauna. micro-flora. macro-fauna.

The forest biome having the greatest Annelid biomass is the: - temperate coniferous forest. tropical forest. temperate broadleaf forest. boreal forest.

The capacity of the soil microflora as a group to decompose a wide variety of organic compounds is due to their: - interspecies specificity. functional diversity. millennium associations. genetic diversity. The mixed angular gravel, rock, and fine earth found at the foot of a slope is typical of what type of parent material? - aeolian. - alluvium. - lacustrine. exfolibi - colluvium.

The factors contributing to the massive species diversity of the soil microflora include: - micro-scale variation in pH & solutes in soil. - micro-scale variation of water & oxygen in soil. - a range of micro-scale physical niches.

-

all of the other options listed.

Exfoliation is an example of: - a physical disintegration process. - a redox reaction. - a biologically mediated disintegration of rock. - a chemical alteration process. Within the glaciated regions of Ohio are stream terraces whose soils were formed from sands and gravels deposited by rapidly flowing glacial meltwater. Which of the following is the parent material of these soils: - till. loess. outwash. alluvium.

Quiz 5 Glacial till is a term used to describe parent materials that: -

were laid down in the bottom of former glacial lakes. were transported by water gushing from glacial fronts.! were deposited directly from melting glacial ice. were transported by high winds during glacial periods.

The weathering of silicate clays to form oxide clays is accompanied by t...