SOIL EROSION – Definition And What Causes This Event
SOIL EROSION – In this topic, we will now talk about the definition of soil erosion and the different factors causing this action or process.
Definition
By definition, erosion is an action or process which involves the removal of soil, rock, or dissolved material from one place from the crust to the other.
This event is caused by many factors. Here are the following:
Causes of Erosion
1. Rain and Overland Flow
Indeed water is the primary leading cause of soil erosion but it comes in many forms, one of which is rain and its aftermath, the overland flow or surface runoff. This result in the four kinds of water erosion:
- Splash erosion – occurs when the impact from raindrop creates a small crater in the soil, thus, ejecting particles.
- Sheet erosion – the result of overland flow. When the flow gains enough flow energy, it can lossen and transport sheets of soil particles
- Rill erosion – it is the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes.
- Gully erosion – happens when runoff water gathers together and rapidly flows in narrow channels during or immediately after heavy rains or melting snow, removing soil to a considerable depth.
2. Rivers and Streams
The second form of water erosion. This erosion was caused by continued water flow along a linear feature. It is both downward and headward. It comes in two forms
- Bank erosion – the wearing away of banks of a stream or river.
- Thermal erosion – the aftermath of melting and weakening permafrost due to moving water.
3. Coastal erosion
Also known as shoreline erosion, occurs on both exposed and sheltered coasts, primarily occurs through the action of currents and waves. Sea level can also be a factor to this kind of erosion.
4. Chemical erosion
The loss of matter in a landscape in the form of solutes. It is usually found from the solutes found in streams
5. Glaciers
Basically ice erosion, they erode into three ways:
- Abrasion/scouring – occurs when debris in the basal ice scrapes along the bed, polishing and gouging the underlying rocks
- Plucking – Occurs when glaciers cause pieces of bedrock to crack off
- Ice thrusting – Occurs when glacier freezes to its bed, then as it surges forward, it moves large sheets of frozen sediment at the base along with the glacier..
6. Floods
The extreme form of water erosion. The large volumes of rapidly rushing water could cause kolks or vortexes, which could cause extreme local erosion, plucking bedrock and creating rock-cut basins.
7. Wind
It is also one of the major causes of soil erosion and is also one of the sources of land degradation, evaporation, desertification, harmful airborne dust, and crop damage. It comes in two forms:
- Deflation – occurs when the wind picks up and carries away loose particles.
- Abrasion – occurs when surfaces are worn down as they are struck by airborne particles carried by wind.
8. Mass Movement
It is the downward and outward movement of rock and sediments on a sloped surface, mainly due to the force of gravity. It is also one of the important part of the erosional process and is often the first stage in the breakdown and transport of weathered materials in mountainous areas.
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