ESC101 Soil Erosion

Causes of Soil Erosion

• The agents of soil erosion are water, wind, ice, and gravity.
• Running water is the primary cause of soil erosion due to its abundance and power.
• Wind is a significant cause, capable of picking up and blowing soil away.
• Activities increasing erosion include removing vegetation, disturbing the ground, or allowing the ground to dry.

Farming

• Agriculture significantly accelerates soil erosion because of the amount of land farmed and disruptive farming practices.
• Farmers remove native vegetation and plow the land for new seeds.
• The land often lies fallow during the stormy winter season, leaving it vulnerable to erosion.
• Tractor tires create grooves that act as pathways for water, enhancing erosion.
• Nutrient-rich topsoil is most susceptible to erosion, degrading farmland.
• Slash-and-burn agriculture is a main cause of soil erosion globally.

Grazing

• Grazing animals expose soil by removing plant cover and churning the ground with hooves.
• Overgrazing happens when too many animals pull plants out by their roots.

Logging and Mining

• Logging removes trees that protect the ground from erosion.
• Tree roots hold soil together, and canopies protect from heavy rain.
• Logging results in loss of leaf litter, which protects forest soils.
• Original forests have been logged, with tropical forests increasingly targeted due to past harvesting in North America and Europe.
• Soil erosion from logged forests clogs rivers and lakes, fills estuaries, and buries coral reefs.
• Surface mining disturbs land and leaves soil vulnerable to erosion.
• Some of the exposed ground from mining is reclaimed by planting trees.
• A coal mine in West Virginia covers more than 10,000 acres (15.6 square miles).

Construction

• Constructing buildings and roads churns up the ground and exposes soil to erosion.
• Native landscapes like forests and grasslands are cleared, increasing erosion.
• Completed construction can still cause erosion.

Recreational Activities

• Recreational activities can accelerate soil erosion.
• Off-road vehicles disturb landscapes, leading to bare spots.
• Even hikers' boots can disturb delicate habitats.

Soil Erosion

• Human activities have greatly accelerated soil erosion, which is a natural process.
• In some areas, soil erosion occurs about 10 times faster than its natural rate.
• About one-third of the topsoil in the present-day United States has eroded since European settlement.

Avoiding Soil Loss

• Terracing prevents soil from moving downhill by slowing water flow.
• Bad farming practices and normal rainfall contributed to the Dust Bowl, with over 75% of topsoil lost in some regions.
• Soil erosion rates are higher than soil formation rates in many global areas.
• Drought, insect plagues, and disease outbreaks negatively impact ecosystems and soil.
• Human actions like neglecting vegetation cover contribute to soil erosion.
• Soil can be contaminated by excessive salt or pollutants.

Soil Conservation

• Soil is a renewable resource with careful management.
• Adding organic material like compost or manure increases soil fertility.
• Inorganic fertilizers temporarily increase fertility without long-term benefits.
• Soil is vital for sustaining natural habitats and growing food.
• Soil is slowly renewable, needing hundreds or thousands of years to develop.
• Crop rotation, alternating crops, and planting cover crops help maintain soil fertility.
• Planting trees as windbreaks and plowing along contours help conserve soil.
• No-till or low-tillage farming minimizes ground disturbance during planting.
• Topsoil loss has decreased in developed countries using better farming practices.

Strategies for Prevention