GEO101 Module 8 Connect

How is soil defined by soil scientists?

Soil is material capable of supporting plant growth.

What caused the Dust Bowl?

The exposure of soil due to tilling A drought

Ion exchange capacity is the ______.

ability of a particular soil to exchange ions with water

The drainage characteristics of the soil affect plant growth because

different species of plants prefer different levels of soil moisture

Permeability is the ability of a

fluid to flow though the interconnected pore spaces within a material

Sediment pollution from soils is likely to result when the ______.

rate of soil erosion increases and soil loss occurs

How are soils derived from rocks? Soils develop as ____

rocks are weathered, form sediment, and then plants and other organisms thrive on it and help to form soil

Soils with an abundance of clay minerals capable of incorporating a large number of water molecules within their structure can ______.

significantly shrink and swell as the volume of the water changes

Loose material capable of supporting plant life is called

soil

Which of the following do food crops such as wheat, corn, and soy need to grow?

soil

are critical to humans because they form the basis of our food supply and provide the raw materials used to produce aluminum metal.

soil

The ability of a soil to support the growth of crops is referred to as ______.

soil fertility

The ability of a soil to form lumps of particles is called soil

structure

Soil fertility is the ability of a soil to ______.

supply the elements necessary for plant growth

Click and drag on elements in order Order the soil horizons found in a soil profile with the layer closest to the surface at the top and the deepest layer at the bottom.

1. o organic matter 2. a organic matter mixed with rock 3.e zone of leeching 4.b zone of accumulation 5. c weathered parent material

Which of the following soils is most likely to swell when water is added?

A soil rich in smectites in the vertisol soil order

How do the E and B horizons form?

Acidic water from the decay of organic matter leaches minerals in the E horizon and deposits them in the B horizon.

The zone of accumulation, named the horizon, is the area in the soil profile in which minerals leached from the E horizon are collected.

B

Acidic water from the A horizon moves downward in the soil profile and leaches soluble minerals from the horizon. Those minerals then accumulate in the horizon.

B and E

What is the role of organic matter and soil organisms in soil fertility?

Biological activity produces certain essential nutrients not produced in the inorganic chemical weathering of minerals. Bacteria and fungi in the soil break down complex organic materials into simpler structures that plants can use.

One soil-forming factor is the parent material (earth materials) from which the soil develops; the other four soil-forming factors are

Blank 1: climate Blank 2: organisms Blank 3: topography, slope, or aspect Blank 4: time

Vegetation acts as a material for soil keeping essential chemical components in and protecting the soil from erosion. Listen to the complete question

Blank 1: cover

Soil loss in the U.S. is concentrated in areas used extensively for

Blank 1: farming or agriculture

This image is showing the two different ways in which occurs in soil.

Blank 1: ion Blank 2: exchange

Old soils are generally infertile because plants and the action of water have removed the essential with time.

Blank 1: ions or nutrients

Which of the following are soil-forming factors?

Climate Organisms Parent material Time Topography

Match the terms for different earth materials to their description.

Dirt matches Choice, The everyday term for the loose, fragmented debris that collects at the surface of Earth The everyday term for the loose, fragmented debris that collects at the surface of Earth Soil matches Choice, The loose material on Earth's surface capable of supporting life The loose material on Earth's surface capable of supporting life Regolith matches Choice, Weathered materials that have not been transported Weathered materials that have not been transported Sediment matches Choice, Earth materials that have been transported by wind, water, or ice Earth materials that have been transported by wind, water, or ice

What are the ways in which ion exchange occurs in soils?

Ions with a weaker attraction to soil particles can replace more strongly held ions if the weaker ions obtain a high concentration in the water. Ions in water having a stronger attraction to soil particles replace ions already attached to the soil that have a weaker attraction.

Why is cover material important for a soil?

It prevents or limits the direct impact of raindrops on the soil and in doing so limits soil erosion. It shelters the soil from wind erosion.

Match the method used to limit soil loss on farms with its description.

No-till farming matches Choice, At the end of the growing season, farmers leave remains of crops in the field rather than plow the field. New crops are planted in the space between the old rows. At the end of the growing season, farmers leave remains of crops in the field rather than plow the field. New crops are planted in the space between the old rows. Strip cropping matches Choice, Different crops are planted in alternating rows within the same field. The rows are often, but necessarily, parallel to the slope of the land. Different crops are planted in alternating rows within the same field. The rows are often, but necessarily, parallel to the slope of the land. Contour plowing matches Choice, Farmers plant rows of crops parallel to the slope of the land. Farmers plant rows of crops parallel to the slope of the land. Grassed waterways matches Choice, Low areas in a farmer's field are not used for farming since they often flood. Instead the soil is protected in the swales by planting noncrop vegetation. Low areas in a farmer's field are not used for farming since they often flood. Instead the soil is protected in the swales by planting noncrop vegetation.

Match the horizons typically found in a soil profile to their descriptions.

O matches Choice, Organic matter Organic matter A matches Choice, Organic matter mixed with mineral fragments Organic matter mixed with mineral fragments E matches Choice, Zone of leaching; dissolved minerals are leached away from this layer Zone of leaching; dissolved minerals are leached away from this layer B matches Choice, Zone of accumulation; iron, aluminum, and clays Zone of accumulation; iron, aluminum, and clays C matches Choice, Weathered parent material Weathered parent material

influence soil development by adding organic matter to soil, creating passageways in the soil that allow for the exchange of oxygen and water, and sometimes by moving particles upward in the soil.

Organisms

Which of the following are essential soil nutrients for plant growth?

Phosphorous Sulfur Magnesium Calcium Nitrogen

Why does the number of soil horizons typically increase as the soil evolves?

Physical and chemical weathering continue to differentiate the soil into more layers.

How does climate control the development of soil?

Rainfall and temperature influence the abundance and diversity of life in and on the soil. Temperatures influence the rate of chemical reactions involved in weathering.

Why is soil loss a problem for humans?

Required farming activities result in the loss of some soil. We could not grown enough food without soil.

What can farmers do to help maintain soil fertility?

Rotate what crops are grown on the field from year to year. Spread fertilizers on fields to add essential nutrients.

Soils contain three grain types: sand, clay, and silt. Match the grain type to the range of sizes it is found in.

Sand matches Choice, 2 - 0.05 mm 2 - 0.05 mm Clay matches Choice, Less than 0.002 mm Less than 0.002 mm Silt matches Choice, 0.05 - 0.002 mm 0.05 - 0.002 mm

Soil texture is a significant factor in how quickly soil drains. Which soil type would drain the fastest?

Sandy

Match the method of limiting soil loss used at construction sites with its description.

Silt fences matches Choice, Physical barriers meant to be temporary are installed to prevent sediment from filling nearby drainage channels. Physical barriers meant to be temporary are installed to prevent sediment from filling nearby drainage channels. Retention basins matches Choice, Human-made depressions are excavated within a drainage system to store excess water and/or sediment. Human-made depressions are excavated within a drainage system to store excess water and/or sediment. Slope vegetation matches Choice, Regraded slopes are replanted immediately following the exposure of the soil. Regraded slopes are replanted immediately following the exposure of the soil.

Why does the permeability of soil differ?

Soils vary in pore spaces; more pore spaces generally mean more permeability. Soils vary in the pecentage of adhesive and cohesive forces; those with more adhesive forces have lower permeability. Soils vary in grain-size distribution; those soils lacking smaller grains have greater permeability.

How do organisms control soil development?

Some organisms move materials within the soils. They create passages in the soil that increase gas and fluid exchange. They contribute organic matter to the soil.

Which of the following methods use significant physical barriers beyond crops themselves to limit soil loss by blocking the movement of soil off of a field?

Terracing Stream buffers Silt fences

Which of the following are true in regard to the problem of soil loss?

The climate and aspect (slope) of the land impact the rate of soil loss.

What is soil porosity?

The fraction of void space in a soil

Which of the following is true about soil?

The nutrients released as water and organisms interact with rocks and minerals help to form the soil on which plants and other organisms depend.

How does the parent material control the types of soil that develop?

The parent material supplies the weathered material from which soils develop.

What is the result of the situation here that portrays an old soil?

The soil becomes acidic.

What is soil structure?

The tendency of clumps of soil to form

How are expanding clays used?

They are used to increase the density of drilling fluids. They are used to absorb liquids.

Swelling clays can be used to ______.

absorb liquids

Farmers use fertilizers and crop rotation to maintain soil fertility because these methods

add or allow certain nutrients in the soil to build back up

Farmers use fertilizers and crop rotation to maintain soil fertility because these methods ______.

add or allow certain nutrients in the soil to build back up

A soil that has a lot of in it will not drain well.

clay

The three primary grain sizes found in soil are sand, silt, and

clay

Temperature and rainfall patterns known as ______ influence the development of soils since they control rates of weathering and the abundance and diversity of organisms.

climate

Soil horizons are formed by processes that result in layers that are

compositionally different from the soil below them

Swelling clays located in a climate with ______ would be expected to cause the most problems.

dry and wet seasons with fluctuating soil moisture

The combination of farming practices that exposed land to erosion and a massive drought created the in the 1930s in the United States.

dust bowl

The movement of soil particles away from where they formed is called soil ______. If the rate of this movement exceeds the rate of soil formation, soil ______ occurs. The washing of soil particles into waterways results in soil pollution.

erosion; loss

Plants are able to get essential nutrients from the soil because the process of ion ______ moves elements such as K+ and Ca2+ from minerals in the soil to soil particles, where they are absorbed by roots.

exchange

The ability of a soil to exchange ions with water is referred to as the ion

exchange capacity

Permeability is the ability of a ______.

fluid to flow though the interconnected pore spaces within a material

Why is ion exchange an important topic in soil science? The process of ion exchange is

how essential nutrients move from minerals in the soil to the plants that use them

A(n) ______ in the ______ content of a soil increases its capacity to shrink and swell.

increase; clay

The continued physical and chemical differentiation that occurs over time in soils results in soils with ______.

more soil horizons

Essential nutrients in the soil for plants include sulfur, phosphorous, potassium, magnesium, ______, and ______.

nitrogen; calcium

The bacteria and fungi living within the soil rely on ______ matter for a food source. They help to break down this matter and make it into simpler substances plants can use directly.

organic

The ability of a fluid to flow through interconnected pore space within a material is referred to as

permeability

The ability of a fluid to flow through interconnected pore space within a material is referred to as ______.

permeability

Soils are important to humans because they

play a critical role in the production of food. influence construction projects provide the raw materials to make aluminum

The amount of void space in a soil relative to the total volume of the soil is called soil ______.

porosity

The processes by which soil horizons develop are related to the

slightly different organic, chemical, and physical processes that are occurring at different soil depths

The processes by which soil horizons develop are related to the ______.

slightly different organic, chemical, and physical processes that are occurring at different soil depths

The general term for the loose material at the surface of Earth is dirt. However, if that loose material can support life, it is called ______ by scientists. If the loose material has been transported, it is called ______; if not, it is called ______.

soil; sediment; regolith

Soil development is influenced by the parent material because ______.

soils are derived from their weathered by-products the parent materials differ in composition different parent materials weather at different rates and in different ways

What is the difference between saturated and unsaturated soils? Saturated soils have

their pores completely filled with water, whereas unsaturated soils do not

If the pore spaces in a soil are filled with both water and air, it is described as ______; once those pore spaces are filled completely with water, the soil is described as ______.

unsaturated; saturated