Impacts of Erosion on Soil, Air, and Water Quality
Objective
By the end of this section the student/user will be able to:
Describe the impacts of erosion on soil, water, and air quality.
Accompanying Exercise: (For Students to print off, complete and turn in for a grade)
Impacts of erosion on soil quality:
Organic matter is a small fraction (2% to 4%) of soil mainly present on the soil surface. Organic matter contributes to productivity through its effect on the physical, chemical, and biological properties of the soil. Erosion gradually depletes organic matter and decreases soil productivity. When organic matter is lost, soils tend to lose their physical structure. The degradation of soil structure makes the soil hard, compact and cloddy. The soil aeration, water-holding capacity and permeability are also decreased. Decreased aeration means less oxygen available for plant roots to grow. Decreased water availability also means less water available for healthy plant growth. When soil permeability decreases, less water will soak into the soil and more will run-off. Beneficial organisms that suppress disease and break down organic residues will not function well due to reduced oxygen and water in soil. This in turn will reduce nutrient storage and supply abilities of the soil.
Impacts of erosion on air quality:
Soil particles blown by the wind into the air have a major impact on human and animal health. Particles suspended in air by wind are easily inhaled and accumulate in lung tissues causing major respiratory problems. Concentrated levels of wind blown particles can also reduce visibility and increase the risk of automobile accidents.
In the 1930’s erosion was the cause of great dust storms. Image by the (NOAA) National Oceanic and Atmospheric Administration/Department of Commerce.
It may be necessary to double click the image to view the video on the right. And click the speaker icon to hear the audio.
Impacts of erosion on water quality:
Sediment deposition in lakes and rivers increases water turbidity making it difficult for light to penetrate the water. This causes problems for aquatic plants that need sunlight for photosynthesis. Sediments are also rich in nutrients such as phosphorus and nitrogen. These nutrients promote the excessive growth of algae. This process is called eutrophication. Areas of excessive algae growth, called algae blooms, deplete oxygen in the water resulting in the death of aquatic animals from lack of oxygen.
The following 3 case studies address different scopes of erosion on water quality; local, national, and world.