Question 1

The lithosphere is made up of _________.
A) air
B) rock
C) water
D) plants and animals
E) all of the above

Accepted Answer

The lithosphere is the outermost solid layer of the Earth and is made up of rock, including both continental and oceanic crust. It does not include air or water, and while some plants and animals may inhabit the lithosphere, they do not make up the lithosphere itself.

Question 2

"Topsoil" is generally equivalent to which soil horizon?
A) A
B) B
C) C
D) D
E) E

Accepted Answer

Topsoil refers to the layer of soil above the subsoil and consists of the A horizon, which is rich in organic matter and supports plant growth. B horizon is rich in minerals and leached materials, C horizon is the transitional layer, D and E horizons are the layers of solid rock below the soil.

Question 3

Which of the following pH values represents a neutral condition?
A) 1.0
B) 5.0
C) 6.0
D) 7.0
E) 10

Accepted Answer

A pH value of 7.0 represents a neutral condition, meaning the solution is neither acidic nor basic. Lower pH values indicate acidic conditions, while higher pH values indicate basic conditions.

Question 4

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?
A) 10% water and 90% air
B) 90% water and 10% air
C) 25% water and 25% air
D) 50% water and 50% air
E) 25% water and 75% air

Accepted Answer

In a typical mineral soil in optimal condition for plant growth, approximately 50% of the pore space would be filled with water and 50% filled with air. This is because plants need both water and oxygen in the soil for proper growth and development, and a balance between the two is crucial. Too much water can lead to waterlogged soils and oxygen depletion, while too little water can lead to drought stress for plants.

Question 5

Hydroxyl ion concentrations are greatest in a soil solution with a pH value of ______.
A) 0.1
B) 4.0
C) 5.0
D) 6.5

Accepted Answer

The pH scale is a measure of the acidity or alkalinity of a solution, with lower values being more acidic and higher values being more alkaline. A pH of 7 is neutral. Hydroxyl ions (OH-) are more prevalent in alkaline conditions. Therefore, among the given options, a pH value of 6.5, being closest to neutral and less acidic than the others, would have the greatest concentration of hydroxyl ions.

Question 6

The layers of contrasting material found when one digs a hole in the ground are called _______.
A) pseudoliths
B) regoliths
C) pedons
D) horizons
E) soil structure

Accepted Answer

Horizons are the layers of contrasting material found when one digs a hole in the ground, typically in reference to soil. Pseudoliths are not a term commonly used in geology or soil science. Regoliths are the layer of loose material covering solid rock, but not necessarily specific layers within that material. Pedons are the basic unit of soil classification and consist of a 3D soil volume that includes all the layers. Soil structure refers to how soil particles are arranged and clump together, but does not specifically refer to layers.

Question 7

In a load of 10 cubic meters of topsoil, approximately how cubic meters of the volume would be solid material?
A) 1
B) 2.5
C) 4
D) 5
E) 7.5

Accepted Answer

The answer of In a load of 10 cubic meters...

Question 8

Which of the following is (are) essential plant nutrients?
A) Cu
B) Al
C) Sr
D) Pb
E) all of the above

Accepted Answer

Copper (Cu) is an essential plant nutrient, required for various physiological functions in plants, including photosynthesis, enzyme activation, and metabolism.

Question 9

Soil occupies the ______part of the regolith.
A) upper
B) lower
C) younger
D) both B and C

Accepted Answer

Soil is the uppermost layer of the regolith which is formed by the weathering of rock and organic matter accumulation. So, soil occupies the upper part of the regolith.

Question 10

In a given soil, the horizon with the highest organic matter content is generally the _____ horizon.
A) E
B) C
C) D
D) B
E) A

Accepted Answer

The A horizon, often referred to as the topsoil, typically has the highest organic matter content due to the accumulation of decomposed plant and animal material.

Question 11

A soil profile consists of _________.
A) the sum of chemical and physical data known about a soil
B) the way a soil "feels"
C) the spatial boundaries of a particular soil
D) the set of layers seen in a vertical cross Section of a soil
E) the general outline of a soil or group of soils when viewed from the side

Accepted Answer

A soil profile consists of the set of layers seen in a vertical cross section of a soil. These layers, or horizons, are typically divided based on physical and chemical characteristics like color, texture, and organic matter content. The soil profile is an important tool for understanding a soil's properties and behavior, and is commonly used in agricultural, environmental, and engineering applications.

Question 12

Which of the following is considered to be a plant macronutrient?
A) N
B) P
C) S
D) Ca
E) all of the above

Accepted Answer

All of the nutrients listed (N, P, S, Ca) are considered to be plant macronutrients. Macronutrients are required by plants in relatively large quantities for growth and development.

Question 13

Most of the different nutrients essential for growth are supplied to plants directly from the ______.
A) rain water
B) soil solution
C) atmosphere
D) cosmic radiation.
E) humus

Accepted Answer

The answer of Most of the different nutrients essential for...

Question 14

"Subsoil" is generally equivalent to which soil horizon?
A) A
B) B
C) C
D) D
E) E

Accepted Answer

The subsoil is usually equivalent to the B horizon, which is located below the A horizon (topsoil). The subsoil contains less organic matter, minerals and nutrients than the topsoil and can be harder and more compact.

Question 15

Compared to silt, clay-sized soil particles are characterized by ______.
A) greater attraction for water
B) greater proportion of primary minerals
C) less tendency to form hard clods when dry
D) less capacity to hold nutrients in plant-available forms

Accepted Answer

Clay-sized soil particles have a greater attraction for water compared to silt, as they have a greater surface area and can hold onto water molecules more effectively. This can lead to problems such as waterlogging and reduced soil aeration, but also makes clay soils more effective at retaining moisture and nutrients for plant growth.

Question 16

Increasing the organic matter content of a soil is likely to _____.
A) have no effect on water holding capacity
B) increase the soil's water holding capacity
C) decrease the soil's water holding capacity

Accepted Answer

Increasing the organic matter content of soil improves soil structure, making it more porous and able to hold more water. Therefore, it increases the soil's water holding capacity.

Question 17

The water in the soil typically differs from pure water because the soil water ________. 5
A) contains organic compounds
B) contains mineral nutrients
C) is restrained in its flow by attraction to particle surfaces
D) all of the above
E) none of the above

Accepted Answer

Soil water contains organic compounds and mineral nutrients, and is also restrained in its flow by attraction to particle surfaces. Therefore, all of the above options are correct.

Question 18

Most (usually 80% or more) of soil potassium and calcium can be found in the form of _________________.
A) dissolved substances
B) structural components of minerals
C) exchangeable ions
D) organic compounds

Accepted Answer

Soil potassium and calcium are mostly present in the form of structural components of minerals like feldspar, mica, and calcite.

Question 19

The amount of different sizes of mineral particles in a soil defines the soil ________.
A) structure
B) texture
C) pore space
D) solution
E) profile

Accepted Answer

The size of mineral particles in a soil is used to determine its texture, which includes the proportions of sand, silt, and clay in the soil. The soil structure refers to the arrangement of the soil particles into aggregates or peds, while pore space refers to the gaps or voids between the soil particles. Solution refers to the chemicals that are dissolved in water that passes through the soil, and profile refers to the vertical layering of different soils in a particular location.

Question 20

Which of the following pH values represents the most acid condition?
A) 1.0
B) 10.0
C) 7.0
D) 100
E) 5.55

Accepted Answer

The lower the pH value, the higher the concentration of hydrogen ions (H+) and therefore the more acidic the solution. A pH of 1.0 represents a very high concentration of H+ ions and is the most acidic of the options given.

Quiz 1: The Soils Around Us

The lithosphere is made up of _________.

"Topsoil" is generally equivalent to which soil horizon?

Which of the following pH values represents a neutral condition?

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?

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

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

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

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

Soil occupies the ______part of the regolith.

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

A soil profile consists of _________.

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

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

"Subsoil" is generally equivalent to which soil horizon?

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

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

The water in the soil typically differs from pure water because the soil water ________. 5

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

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

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