Embedded Files
Overview:
Overview:
In this activity you will examine the impacts of human activities, such as agriculture, industry, and construction, on soil quality.
Content:
Content:
As you have discovered, the lithosphere contains the land portion of the Earth. Soil is a key component of the lithosphere. As discussed, soil has four components, mineral matter, organic matter, air, and water. Different ecosystems have different types of soil determined by the texture, mineral components, organic components, size of mineral particles, and water content. Soil provides nutrients necessary for plant growth and is the basis of terrestrial ecosystems. Humans use the land and soil for their own benefit, for food and shelter. Whenever humans use a natural resource, such as the soil, they affect the environment, sometimes in a positive way and more commonly, in a negative way.
As you have discovered, the lithosphere contains the land portion of the Earth. Soil is a key component of the lithosphere. As discussed, soil has four components, mineral matter, organic matter, air, and water. Different ecosystems have different types of soil determined by the texture, mineral components, organic components, size of mineral particles, and water content. Soil provides nutrients necessary for plant growth and is the basis of terrestrial ecosystems. Humans use the land and soil for their own benefit, for food and shelter. Whenever humans use a natural resource, such as the soil, they affect the environment, sometimes in a positive way and more commonly, in a negative way.
Natural Ecosystem:
Natural Ecosystem:
Ecosystems that have had no, or minimal, human impact or influence on them are considered natural ecosystems. An old-growth forest is a natural ecosystem where humans have had no or minimal influence, and nature is left alone. In this situation, the soil supports a wide variety of plant and animal life in a sustainable manner. Nutrients are cycled and the quality of the soil is either stable or will improve over time.
Disturbed Ecosystem:
Disturbed Ecosystem:
Ecosystems that have been impacted, or influenced, by human activity are considered to be disturbed ecosystems. A schoolyard or a park is an example of a disturbed ecosystem. Humans have affected this ecosystem by using it for their own purposes. Disturbed ecosystems usually have to be maintained by people, since the natural cycles of the environment have been disturbed. Many areas of human intrusion are actually toxic to all life. An example of this is the Chernobyl reactor site.
Check Your Understanding:
Check Your Understanding:
Identify the following ecosystems as natural or disturbed.
The continent of Antarctica lies over the South Pole. It has no permanent human residents and is protected as a world nature preserve.
Downsview Park in Toronto is Canada's first urban National Park, it features sports fields, a museum, and a nature centre, as well as lots of green space.
The Pinery Provincial Park on the shores of Lake Huron features forests with great hiking trails, campsites, and a long sandy beach.
Human Impact on Soil Quality
Human Impact on Soil Quality
Various forms of land use, including crop production, animal grazing, and urbanization, have negatively impacted the soil quality in a variety of ecosystems.
Agriculture
Agriculture
Livestock and heavy equipment compact the soil, reducing the amount of air and water in the soil, making it difficult for plants to grow. Pesticide residues may contaminate the soil, making it unsuitable for some activities and disrupting the natural biological communities in the soil responsible for nutrient cycling.
Global topsoil depletion is considered a serious human crisis. Previous civilizations have collapsed as a result of unsustainable agriculture. Our modern agricultural system could be called “dirt mining” in which long term devastation is the result of short term profit-taking from the stored biological riches in the soil.
Deforestation
Deforestation
The clear cutting of trees exposes the topsoil to erosion by wind and water, resulting in the potential loss of topsoil and nutrients from the ecosystem. The temperature fluctuations, erosion, lack of moisture and increased wind, hinder any regeneration (natural or man-made tree plantations) in this large scale disruption of the natural ecosystem
Industry
Industry
Hazardous wastes from manufacturing processes may pollute the soil, making it unsuitable for some activities until it is cleaned up. There are numerous sites across Canada that have contaminated soil in need of clean up. Industries frequently deny their role or declare bankruptcy in order to avoid their responsibility to clean up the mess they created.
Construction
Construction
The clearing of land for building and road construction strips the soil of vegetation and results in large amounts of dust and loss of topsoil. Heavy machinery compacts the soil and disturbs the soil layers, changing its soil profile.
Lawns and chemical use
Lawns and chemical use
The use of fertilizers and pesticides on lawns disrupts natural cycles in the ecosystem, and may contaminate the soil. Some people are also worried about the health risks of using chemicals on lawns and gardens for purely cosmetic appearances. In addition, the fossil fuels burned in inefficient lawn mowers and leaf blowers, further degrades the environment
Classwork:
Classwork:
The purpose of this assignment is to allow you to gain an appreciation of the limited amount of land available to supply the energy needs of the Earth's population. You will need an average-sized apple (or imagine an apple) to complete this activity.
Steps
Steps
Let the apple represent Earth.
Slice the apple into quarters.
Set aside three of the four quarters of the apple. These three quarters represent the oceans of the world.
Slice the remaining apple quarter in half.
Set aside one of the pieces. This portion represents inhospitable land areas such as polar areas, deserts, and mountains.
Slice the remaining piece of apple into four sections.
Set aside three of these sections. These three sections represent areas that are too cold, wet, steep, or have soil too poor to produce food. They also include cities, roadways, and other places where people live.
Peel the remaining piece of apple. The peeling represents Earth's surface, or the topsoil on Earth. It is less than 30 cm deep, and it takes at least fifty years for a centimetre of topsoil to form
Next: Go to Google Classroom and complete and submit the following questions:
What fraction of the Earth's total surface is topsoil, based on the apple activity?
Can food be grown in places other than farmland? List these places.
Is the thin layer of topsoil on Earth increasing or decreasing? Explain your answer.
It has been hypothesized that the world population will exceed 8.5 billion by the year 2030. How might this population growth have an impact on food availability? Explain your answer based on what you already know about land availability.
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