Exam 1

A Horizon

This horizon contains more organic material than any other horizon except the O Horizon. Some components may have been leached downward from this horizon.

The means by which rocks and minerals are changed by physical and chemical processes into other soil components describes which of the following terms?

Weathering

Many soil materials were transported before soil formation began. What mode of transportation is associated with Loess parent materials?

Wind

For the monolith of the 'Fillmore' soil series, the first 'Subsoil' layer ('B' horizon) was also described as:

cracking due to clay shrinking

Soil is composed of both abiotic and biotic elements. From the list below, select the FOUR BIOTIC elements of soil.

Plant Roots Decomposers Organic Residues and Humus Insects

Soil fertility and soil productivity are two terms for the same concept.

False

If a late spring rainstorm drops 2.5 inches of rain on a gently sloped landscape in 2 hours... Which soil textural types will have the greatest amount of surface runoff?

Fine

If a late spring rainstorm drops 2.5 inches of rain on a gently sloped landscape in 2 hours... Which soil textural types would likely retain the most water 3 days after the storm?

Fine

O Horizon

Found commonly in undisturbed forests or wetlands. It consists mainly of organic materials in varying stages of decomposition.

The B horizon is characterized as a...

Horizon that has the most accumulated clay

The A horizon is characterized as a....

Horizon that is mainly mineral but also has organic matter

Surface accumulation of recently dead organisms and organic materials, may be slightly decomposed.

Organic Layer (O Horizon)

Many soil properties affect the ability of soil to function as a 'Medium for Plant Growth'. Check the list the of soil properties below and identify all those that would be considered CHEMICAL properties of soils. Select FOUR that apply.

Organic Matter Content Acidity - Alkalinity (pH) Salinity - Soluble Salts (EC) Nitrate Nitrogen

Soil and water are intimately connected in the environment. Which soil properties will most directly affect the ability to regulate water supply? Identify five of the listed soil properties that directly affect water intake and storage in soils.

Organic Matter Content Texture and Aggregation Aeration and Infiltration Surface Cover Soil Compaction (Density)

What are the five factors that work in concert to produce a soil profile?

Parent Material Climate Organisms (Vegetation and Biota) Relief (Topography) Time

Mainly un-weathered, loose material. Unconsolidated.

Parent Material (C Horizon)

In the video "A Look at Soil", the identified functions of soil included which of the following?

Producing food and fibers Providing nutrients to plants Disposal of the waste products

B Horizon

Receives materials such as clay, lime, and salts which have leached out of the horizons above it.

What benefit do soil organisms provide to the soil ecosystem by their activities?

Recycle old dead materials into raw materials needed for growth Aeration into soil Soil structure (fungi?)

Soil functions include _________ . Choose 3 of the following:

Recycles dead organisms Home to organisms Purifies and stores water

Subsoil

Rich in elements above, chemically active but biologically inert and below topsoil layer B & Chorizons

The ability of a soil to function, to sustain biological productivity, to maintain environmental quality, and to promote plant and animal health is ________

Soil Quality

Many soil properties affect the ability of soil to function as a 'Medium for Plant Growth'. Check the list the of soil properties below and identify all those that would be considered BIOLOGICAL properties of soils. Select FOUR that apply.

Soil Respiration (CO2) Microbial Activity / Biomass Earthworm Counts Plant Vigor

Which of the following statements regarding soil productivity and soil fertility is most accurate?

Soil fertility is one thing that affects soil producivity.

Subordinate horizons

Soil layers designated by lowercase letters to indicate specific characteristics of a master horizon

Soil is the interface of Earth's ecosystems. An "ecosystem" is ...

...a body of relationships that connect a community of living things with their environment and each other.

Humus

1) organic materials in or on a soil that are in an advanced stage of decomposition 2) Product of soil organsims that undergoes continuous breakdown, change and synthesis. 3) previously living tissues that have been repeatedly consumed and/or digested by variety of soil organisms, coats soil particles and darkens their underlying colord due to its high percentage of carbon.

Which of the following is the expected sequence of horizons in an undisturbed soil profile?

A, B, C

Soil quality

Ability of a soil to function, within ecosystem boundaries, to sustain biological productivity, maintain environmental quality, and promote plant and animal health.

Surface Litter

Accumulation of recently dead organisms.

Soil chemical properties include ________. Choose 2 of the following:

Acidity Organic Matter

Biota directly influences soil formation by affecting the:

Amount of organic matter and pore

According to the course notes, which of the following relationship of rainfall and temperature to weathering is TRUE?

As annual rainfall and temperature increase, chemical weathering dominates over physical weathering.

Subsoil is expected to be....

B & C Horizons

Consolidated, rocky material

Bedrock (R Horizon)

Soil productivity

Capacity of a soil, in its particular environment to produce plants under a defined management system.

If a late spring rainstorm drops 2.5 inches of rain on a gently sloped landscape in 2 hours... Which soil textural types will allow the most rapid rate of water infiltration?

Coarse

If a late spring rainstorm drops 2.5 inches of rain on a gently sloped landscape in 2 hours... Which soil textural types will have the most rapid rate of drainage (internal)?

Coarse

C Horizon

Consists of loose parent material which is essentially unaffected by soil forming processes

Bedrock

Consolidated, rocky material

Soil Texture

Content of sand, silt, and clay particles in a soil. Described as: fine- clayey, medium- loamy, or coarse - sandy.

The parent material for soils formed in organic materials is called:

Cumulose

Soil Structure

Describes shape, size and strength of aggregated soil particles.

Which horizon is severely leached and has lost significant amount of clay, iron, aluminum, and salts?

E Horizon

Which soil profile horizon is noted for being highly leached and is typically acidic?

E Horizon

E Horizon

It is very severely leached, typically due to decomposition of acidic vegetation and or frequent saturation with water

Soil Horizons are

Layers of soil in a soil profile

Master Horizons

Layers of soil with distinctive characteristics O A E B C R

Soil is the interface of Earth's Ecosystems, a global 'Super-ecosystem'. From the list below, select the FOUR components of the soil ecosystem identified in the video "A Look at Soil".

Living Organisms (Life) Water Minerals Air

From the list below, select the FOUR that have been identified as soil forming processes.

Losses Additions Transformations Translocations

Topsoil

Major site of biological activity - Where humus is stored. Moved or distrubed by cultivation- consists of O, A, & E horizons.

Identify the five over-arching general functions in the list of soil functions below.

Medium for plant growth Regulator of water supplies Recycler of raw materials Habitat for soil organisms Landscaping and engineering medium

Which is the most numerous creature in soil?

Microorganisms- bacteria

Organic matter is composed of several chemical elements. Which of the following elements is most influential in controlling the rate of organic matter decomposition. In other words: Residue with a greater _______ content, will decompose faster.

Nitrogen

Which horizon is found more often in forest soil than under grasslands?

O Horizon

Which horizon is mainly composed of organic material in various stages of decay?

O Horizon

Topsoil is expected to have:

O and A horizons The most biological activity The highest organic matter content The most disturbance

R Horizon

Solid rock parent material which has not been significantly affected by soil forming processes

Layer of clay accumulation, with other elements accumulating that have moved down from above.

Subsoil (B Horizon)

Soils are the base material for roads, homes, buildings, and other structures set upon them, but the physical properties of different soil types may be greatly variable. The type of solid soil particles (textural class) and the amount and size of the empty spaces between them (porosity and structure) determine how a soil will behave when used as foundations for buildings and roads. Select four of the following soil properties that will be of greatest interest to an engineer designing a roadway or building foundation?

Textural Class (% of Sand, Silt, and Clay) Structure and Aggregation Soil Depth Soil Density (Compaction)

Soil is home for an enormous variety of living organisms (plants, insects, microorganisms, etc.). Which of the following soil properties will have the greatest influence on the ability of the soil to provide a suitable habitat for these organisms?

Textural Type Porosity (Aeration) Organic Matter Type and Composition Soil Water Content

Soil fertility

The ability of a soil to supply nutrients necessary for plant growth.

Why do green or grassy plant residues usually decompose faster than woody residues?

They generally contain more protein, and thus more nitrogen than woody-type residues.

The effects of drainage on soil formation are closely related to, and hard to distinguish from, the effects of ___________.

Topography

Layer of greatest biological activity and humus accumulation.

Topsoil (A Horizon)

Many soil properties affect the ability of soil to function as a 'Medium for Plant Growth'. Check the list of the soil properties below and identify all those that would be considered PHYSICAL properties of soils. Select FIVE that apply.

Topsoil Depth Texture and Aggregation Aeration and Infiltration Surface Cover Soil Compaction (Density)

Parent Material

Unconsolidated, unweathered, loose material.

The C horizon is characterized as a/an...

Unformed soil layer in loose parent material

From the list below, select the FIVE that have been identified as soil forming factors.

Vegetation/Biota Topography Climate Parent Material Time

Soil Profile is a ...

Vertical cross section of all soil horizons

Creatures that live in soil

Very small mites, insects, microorganisms (bacteria), fungi, earth worms, protozoa

Soil is composed of both abiotic and biotic elements. From the list below, select the FOUR ABIOTIC elements of soil.

Water Minerals Air Clay

Which of the essentials for life do plants receive from the soil? Choose 2 of the following:

Water Nutrients

For the monolith of the 'Hastings' soil series, the structure of the first 'Subsoil' layer ('B' horizon) was described as:

blocky or fine-blocky structure

What or whose activity is responsible for the formation of humus in soil?

fungi, bacteria, invertebrates, decomposers

According to the video 'How Dare We Call it Dirt! - A Look at Soil', Which of the following is a benefit of 'Humus' to soil health?

improves water retention and infiltration promotes porosity and structure soil binder aggregate stabilizer

According to the "official" definiton of soil, which of the following are true? Mark five statements which are true.

naturally occurring formed in place includes all materials less than 2 mm in diameter occupies top two meters of lithosphere unconsolidated materials

For the monolith of the 'Aksarben' soil series, the structure of the surface layer (0 - 10 cm) was described as:

well-granulated structure