The Dirt on Soil Conservation

Chris Langley
Readability
7.4

How does this align with my curriculum?

If I asked you to name a few things that all life on the planet couldn’t live without you could probably come up with some good answers, but I bet you’d never think to say dirt.

What does life on earth need to survive? You probably think of food, sunlight, and water, right? These things are important, but I bet you’d never think to say soil. It’s easy to forget that soil plays a very important role in supporting all life on Earth!

What is soil?

Soil makes up the top layer of the Earth’s surface. The layer that contains soil, where soil-forming processes happen, is called the pedosphere. Soil is made of minerals, water, air, and broken down organic material. This organic material can be things like leaves, roots, twigs, and bugs.

Cross-section of sandy soil
Cross-section of sandy soil (Source: georgeclerk via iStockphoto).

What living things depend on soil?

You probably know that plants grow in soil and get water and nutrients from it. But you may not know that soil is home to an ecosystem of its own. 

Soil is filled with organic and inorganic nutrients that are used by plants and microorganisms like bacteria and fungi. These microorganisms are a food source for other animals, like insects. Insects are then eaten by larger animals like mice and birds, which are eaten by other animals, like hawks or foxes. 

Soil is the foundation of every terrestrial (land-based) food chain on Earth. Without soil, it would be very difficult for plants and microorganisms at the bottom of these food chains to grow. So, the health and conservation of soil are very important.

Terrestrial food chains including soil
Terrestrial food chains including soil (Let’s Talk Science using images by lukaves via iStockphoto).

How can soil be damaged?

Soil can be damaged when something harmful is added to it, or when nutrients are taken away from it. Land pollution is when solid waste, liquid waste, or pesticides are added to soil on purpose or by accident. Land pollution is a major contributor to soil contamination

Solid waste, like the garbage in landfills, takes up land and can get mixed up in the soil. This can make it difficult for plants to grow because there isn’t enough space on land or underground for their roots. 

Soil at a landfill site
Soil at a landfill site (Source: vinhdav via iStockphoto).

Liquid waste from landfills, factories, and farms can contaminate soil. This happens when chemicals leak into the soil and make it poisonous or remove its nutrients. If soil is contaminated, plants and microorganisms are not able to live in it. 

Pesticides are chemicals that people spray on farms or in gardens. These chemicals protect the plants we are growing by killing unwanted insects, fungi or competing plants such as weeds. But if too many pesticides are used, they can build up in the soil and kill important microorganisms, along with the insects. People can choose to use pesticides that break down easily, and do not build up over time. Or they can use pesticides made of natural materials, such as soap, that get rid of the insects with little to no environmental impact

Soil can also be damaged when nutrients or water is lost from it. This can happen through irresponsible ways of farming, or through erosion. 

Tillage is the process of digging and turning over soil to remove the weeds that compete with crop plants. But if the farmland is on a hill, tillage can move nutrient-rich soil down the hill, leaving the higher soil without nutrients.

Tractor tilling soil
Tractor tilling soil (Source: MartinLisner via iStockphoto).

Desertification is when soil loses so much water that nothing can grow in it. This soil becomes a type of land called drylands. Drylands now cover over 40% of Earth’s land, and many organisms have a difficult time living in or on it.

Erosion from wind or water can cause nutritious topsoil to be removed from an area. This can happen slowly or very quickly. Water erosion often happens when there is a lot of rainfall. It can also happen when snow melts and the ground thaws in the spring, causing water runoff. Wind erosion happens when the wind moves small particles of soil long distances or moves larger particles of soil around. This affects the way nutrients are spread through the soil, making it hard for organisms to survive in it. 

Soil erosion on a farm
Soil erosion on a farm (Source: NeilBradfield via iStockphoto).

Did you know?

Due to poor farming methods, fertile soil (soil where plants and organisms can grow) is being lost at a rate of about 24 billion tonnes per year. This is one-third of the Earth’s total soil.

What is soil conservation?

Soil conservation includes many ways to reduce soil damage. It is often used in forestry and farming. 

Farmers can choose to use composted manure to fertilize their plants, instead of chemical fertilizers that can damage soil. Farmers can also use crop rotation, switching up the kinds of crops that are planted in a certain area. This way, the soil will not lose as many nutrients as it would if it only contained one crop for a long time. Conservation tillage describes a number of ways farmers can till while protecting the soil. For example, changing the time of year that they till, and changing the way they till, can help the soil keep its nutrients. 

To prevent wind and water erosion, farmers can leave a layer of mulch over their crops. This is called mulching. Buffer strips, or conservation buffers, can also be used to prevent wind and water erosion. These are barriers such as trees, alfalfa crops, or waterways that block the wind or provide water with a route to pass through farmland without removing the soil.

Buffer strip of trees
Buffer strip of trees (Source: TT via iStockphoto).

When you consider the importance of the dirt beneath your feet and support biodiversity and life on Earth, you can’t help but want to protect it!

Infographic which shows why soil is important
Infographic which shows why soil is important (© Soil Conservation Council of Canada. Used with permission).

 

 

Starting Points

Connecting and Relating

  • Where have you seen land that has been eroded? What was the cause of the erosion? 
  • Have you ever thought of soil as something that could be healthy or not healthy? Why or why not? 
  • What soil conservation practices have you observed?
  • What things can you and your family do to protect and conserve soil?

Connecting and Relating

  • Where have you seen land that has been eroded? What was the cause of the erosion? 
  • Have you ever thought of soil as something that could be healthy or not healthy? Why or why not? 
  • What soil conservation practices have you observed?
  • What things can you and your family do to protect and conserve soil?

Relating Science and Technology to Society and the Environment

  • Should governments put restrictions on the development of land for urbanization to preserve soil resources? Why or why not? 
  • Why are many urban regions restricting the use of pesticides? 
  • What could be the impact of climate change on global soil resources?

Relating Science and Technology to Society and the Environment

  • Should governments put restrictions on the development of land for urbanization to preserve soil resources? Why or why not? 
  • Why are many urban regions restricting the use of pesticides? 
  • What could be the impact of climate change on global soil resources?

Exploring Concepts

  • What factors can impact the health of soil?
  • How can the overuse of pesticides affect soil health? 
  • What are some methods that can be used to decrease soil erosion? 
  • Conduct additional research to explore different methods of conservation tillage.

Exploring Concepts

  • What factors can impact the health of soil?
  • How can the overuse of pesticides affect soil health? 
  • What are some methods that can be used to decrease soil erosion? 
  • Conduct additional research to explore different methods of conservation tillage.

Media Literacy

  • Students could watch Dirt! The Movie (2009), a documentary which highlights the environmental, economic, social, and political importance of soil.

Media Literacy

  • Students could watch Dirt! The Movie (2009), a documentary which highlights the environmental, economic, social, and political importance of soil.

Teaching Suggestions

  • This article can be used to support teaching and learning of Earth Science, Soil, Science and Earth materials/processes related to the pedosphere, soil and erosion. Concepts introduced include soil, organic, pedosphere, ecosystem, microorganisms, terrestrial, land pollution, contamination, landfills, leach, pesticides, tillage, desertification, erosion, topsoil, soil conservation, crop rotation, conservation tillage, mulch and buffer strips. 
  • Before reading this article, teachers could have students use a Vocabulary Preview to engage their prior knowledge and introduce new terminology. Ready-to-use Vocabulary Preview reproducibles for this article are available in [Google doc] and [PDF] formats. 
  • After reading this article, teachers could have students in groups brainstorm the many ways in which humans interact with soil and depend on soil (the pedosphere) as a resource. Students could present gathered information in a graphic organizer or an infographic
  • Humans need land and soil not only as a resource for growing food, but also as a space to live. Using a Pros & Cons Organizer learning strategy, teachers could have students consider the positive and negative impacts on the soil of building a new 200 ha (~500 acre) housing development on A1 agricultural land in Canada. A ready-to-use Pros & Cons Organizer reproducible for this article is available in [Google doc] and [PDF] formats.

Teaching Suggestions

  • This article can be used to support teaching and learning of Earth Science, Soil, Science and Earth materials/processes related to the pedosphere, soil and erosion. Concepts introduced include soil, organic, pedosphere, ecosystem, microorganisms, terrestrial, land pollution, contamination, landfills, leach, pesticides, tillage, desertification, erosion, topsoil, soil conservation, crop rotation, conservation tillage, mulch and buffer strips. 
  • Before reading this article, teachers could have students use a Vocabulary Preview to engage their prior knowledge and introduce new terminology. Ready-to-use Vocabulary Preview reproducibles for this article are available in [Google doc] and [PDF] formats. 
  • After reading this article, teachers could have students in groups brainstorm the many ways in which humans interact with soil and depend on soil (the pedosphere) as a resource. Students could present gathered information in a graphic organizer or an infographic
  • Humans need land and soil not only as a resource for growing food, but also as a space to live. Using a Pros & Cons Organizer learning strategy, teachers could have students consider the positive and negative impacts on the soil of building a new 200 ha (~500 acre) housing development on A1 agricultural land in Canada. A ready-to-use Pros & Cons Organizer reproducible for this article is available in [Google doc] and [PDF] formats.

Learn more

What makes soil hard and compacted? 

This hands-on activity by Let’s talk Science explores how walking on soil changes how water soaks into the ground and why that matters to gardeners and farmers.

Soil Conservation Council of Canada

Participate in national Soil Conservation Week or the Soil Your Undies program to learn about soil conservation.

Soil Conservation (2015)

This article by The Canadian Encyclopedia includes information on land use, conservation practices as well as soil health by region.

Soil Erosion Round the World - Causes and Solutions (2015)

This video by DW News (3:37 min) discusses types of soil erosion, including water erosion, wind erosion, excessive farming, and how it impacts different countries around the world and some possible solutions to these issues. 

Earthrise - The Great Green Wall (2011)

This video by Al Jazeera English (5:58 min) is about a project fighting desertification in Senegal, and its effects on the people and the land. 

References

National Institute of Environmental Health Sciences (2020). Pesticides.https://www.niehs.nih.gov/health/topics/agents/pesticides/index.cfm

Nelson, K. (2020). Environment for Kids: Land Pollution. https://www.ducksters.com/science/environment/land_pollution.php 

Nova Scotia Environmental Farm Plan. (2018, April). Soil Conservation Practices. https://www.perennia.ca/wp-content/uploads/2018/04/soil-conservation-and-practice.pdf

Ritter, J. (2018). Soil Erosion - Causes and Effects. http://www.omafra.gov.on.ca/english/engineer/facts/12-053.htm#6

Soils 4 Kids. (n.d.). What Is Soil? https://www.soils4kids.org/about

Weathering and Soil. (n.d.). Soil Damage and Loss. https://sites.google.com/site/weatheringandsoil/home/soil-damage-and-loss

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