COE113 Environmental Science Lecture 13

Questions and Answers

What is the primary consequence of soil erosion on agricultural productivity?

It improves the fertility of the soil

It enhances the biodiversity of soil organisms

It leads to the loss of fertile soil (correct)

It increases water retention in the soil

Which natural cause can lead to soil erosion through the movement of water?

Heavy rainfall causing surface runoff (correct)

Volcanic activity modeling the landscape

Plant roots stabilizing the soil

Strong winds displacing topsoil

How does deforestation contribute to soil erosion?

By increasing soil nutrient levels

By removing vegetation that anchors soil (correct)

By exposing the soil to stronger winds

By enhancing the growth of other plants

Which agricultural practice is a contributor to soil erosion?

Overgrazing livestock Signup and view all the answers

What impact does monoculture farming have on soil erosion?

It leads to nutrient depletion and soil degradation Signup and view all the answers

What role does gravity play in soil erosion on steep slopes?

It causes landslides and mudslides Signup and view all the answers

Which of the following methods can help control soil erosion?

Planting cover crops Signup and view all the answers

What is a potential result of urbanization related to soil erosion?

Exposing subsoil to erosion Signup and view all the answers

What is one benefit of afforestation and reforestation in controlling soil erosion?

Reduces wind speed Signup and view all the answers

Which method involves planting crops during off-seasons to protect soil?

Cover crops Signup and view all the answers

What is the primary purpose of creating terraces on steep slopes?

To allow water infiltration and reduce runoff velocity Signup and view all the answers

How do check dams and silt fences primarily prevent erosion?

By trapping sediment and reducing flow speed Signup and view all the answers

Which method of soil erosion control minimizes soil disturbance through farming techniques?

No-till farming Signup and view all the answers

What is the purpose of mulching in soil management?

To protect soil from erosion and retain moisture Signup and view all the answers

What is a function of drainage control in managing soil erosion?

Directs water away from vulnerable areas Signup and view all the answers

What does contour plowing do to minimize soil erosion?

Reduces water runoff speed Signup and view all the answers

What is the primary benefit of rainwater harvesting in agricultural contexts?

It reduces surface runoff. Signup and view all the answers

Which method is NOT part of the treatment options for contaminated soil?

Geothermal heating Signup and view all the answers

What is a major challenge associated with soil contamination in urban areas?

Industrial and manufacturing activities. Signup and view all the answers

What role do micro-organisms play in bioremediation?

They breakdown and transform contaminants. Signup and view all the answers

Which of the following contaminants can bioremediation effectively mitigate?

Non-chlorinated pesticides Signup and view all the answers

What is the potential drawback of using bioremediation for soil decontamination?

It can be time-consuming. Signup and view all the answers

How does chemical oxidation treat contaminated soil?

By converting contaminants into less harmful substances. Signup and view all the answers

Which process involves the addition of immobilizing agents to soil?

Soil stabilization Signup and view all the answers

What is the primary purpose of chemical oxidation in soil treatment?

To achieve rapid and complete contaminant destruction Signup and view all the answers

Which of the following contaminants can chemical oxidation treat?

PCBs Signup and view all the answers

How does soil stabilization primarily reduce risks from contamination?

By binding contaminants in place to prevent their movement Signup and view all the answers

What does soil washing achieve in terms of soil treatment?

It separates fine grained soils that bind to contaminants Signup and view all the answers

Why is soil remediation important?

It mitigates health risks posed by contaminated soil Signup and view all the answers

What is a significant benefit of Enva operating a licensed contaminated soil treatment facility?

It eliminates the need for soil transportation off-site Signup and view all the answers

What does the addition of immobilizing agents in soil stabilization accomplish?

It reduces the bioavailability of contaminants Signup and view all the answers

What is a major limitation of soil washing as a treatment method?

It does not remove contaminants from soil, necessitating disposal Signup and view all the answers

Study Notes

Soil Erosion

Soil erosion involves the removal of the topsoil layer by natural forces like wind and water, as well as human activities.
Consequences include loss of fertile soil, agricultural productivity decline, and environmental damage.
Erosion can lead to desertification, habitat loss, decreased soil water retention, and nutrient depletion.

Root Causes of Soil Erosion

Natural Causes:
- Water Erosion: Heavy rainfall causes surface runoff that dislodges soil; rivers erode banks and create gullies.
- Wind Erosion: Strong winds transport dry soil particles, especially in arid regions, causing dust storms.
- Gravity: Landslides and mudslides on steep slopes can rapidly shift large soil volumes, triggered by heavy rains or seismic activities.
Human-Induced Causes:
- Deforestation: Clearing vegetation for agriculture loosens soil, increasing vulnerability to erosion.
- Agricultural Practices: Overgrazing by livestock and monoculture farming degrade soil and make it prone to erosion. Improper plowing techniques exacerbate runoff.
- Urbanization: Construction exposes subsoils to erosion; urban runoff from impervious surfaces further accelerates erosion.

Methods of Controlling Soil Erosion

Vegetative Methods:
- Afforestation and Reforestation: Planting trees stabilizes soil through root systems and reduces erosive impacts.
- Cover Crops: Growing plants like clover or rye enhances soil structure and prevents erosion during off-seasons.
- Contour Plowing: Plowing along slopes decreases runoff speed and mitigates erosion.
- Terracing: Creating steps on sloped land reduces runoff velocity and aids water infiltration.
Structural Methods:
- Check Dams and Silt Fences: Barriers slow water flow and trap sediment, mitigating downstream erosion.
- Retaining Walls: Stabilize soil in landslide-prone areas and impede erosion.
- Riprap: Large stones on slopes absorb energy from water, protecting against erosion.
Soil Management Techniques:
- No-Till Farming: Preserves soil structure and minimizes erosion.
- Mulching: Protects soil surface from raindrop impact and retains moisture.
- Contour Bunding: Embankments along contours slow water flow and enhance infiltration.
Water Management:
- Drainage Control: Proper drainage systems reduce erosion risk by directing water away from vulnerable areas.
- Rainwater Harvesting: Reduces runoff and supplies water, alleviating erosion stress on soil.

Methods of Soil Treatment

Soil contamination arises from improper management of hazardous substances, prevalent in urban areas and former industrial sites.
Contaminants may be surface-applied or leaked into the soil from underground sources like tanks and pipes, potentially impacting groundwater.

Soil Treatment Techniques

Bioremediation: Utilizes microorganisms to degrade or transform contaminants. Effective against hydrocarbons, various organic solvents, and metals.
Chemical Oxidation: Involves injecting oxidants into contaminated areas, facilitating rapid contaminant destruction, ideal for difficult-to-access soils.
Soil Stabilisation: Enhances safety by locking contaminants in place, improving soil structure for construction through immobilizing agents.
Soil Washing: Cleans soil by separating contaminants using liquid solutions, necessitating careful disposal of residual contaminated materials.

Importance of Soil Remediation

Essential for mitigating health risks associated with contaminated soil; procedures include testing, investigation, and treatment.
Enva offers comprehensive soil remediation services, including the only licensed treatment facility in Ireland, which can reduce costs for soil management.

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Description

This quiz covers Lecture 13 of COE113, focusing on soil pollution control, soil erosion, and methods for treatment and prevention. Participants will gain insights into the natural and human factors contributing to soil erosion as well as effective control measures.