What is soil erosion?

What is soil erosion?

Soil erosion is a three-phase process in which soil particles are detached, transported, and deposited by physical forces such as rainfall, flowing water, wind, and ice. It is a major form of land degradation worldwide. The soil degradation indicators presented by the EUSO soil degradation¹ dashboard identify 5 types of soil erosion: erosion by water, erosion by wind, harvest erosion, tillage erosion and post-fire recovery. In this MOOC, we present erosion by water, as it is the most widespread erosion process in Europe.

Types of Soil Erosion by water

Rainsplash and water running over the soil surface detach and transport the detached soil particles.

Screenshot from the movie: https://vimeo.com/1173230664/68301a4d6f <<movie 1>> (© Jannes Stolte/NIBIO).

This encompasses the following processes:

Rainsplash:

The soil particles are displaced by raindrop impact. (No changes were made to the original photo. source: unknown)

Sheet erosion:

Water running as a shallow sheet (overland flow) and displacing a relatively uniform thickness of soil. (No changes were made to the original photo. © Jannes Stolte/NIBIO).

 Rill erosion: 

This refers to water moving as concentrated flow and removing soil by “digging out” channels, resulting in small rills formed by concentrated water flow. (No changes were made to the original photo. © Jannes Stolte/NIBIO).

  Gully erosion:

Severe cases of rill leading to the formation of gullies that are either temporary (left) or permanent (right). (No changes were made to the original photo. © Jannes Stolte/NIBIO).

Historical Context

Humans have observed erosion since ancient civilizations, but scientific study began in the early 20th century. Soil erosion by water and wind has been occurring naturally. There is archaeological evidence from many parts of the world that water erosion is often linked to early agriculture. In a scientific context, the connection between water erosion and agricultural practices was first identified in the early 20th century in the USA, and subsequently in other parts of the world. Today, water erosion is recognised as one of Europe’s most widespread soil degradation threats.

Consequences

Erosion by water leads to several negative consequences, both on-field and off-field.

On-field:

Loss of fertile topsoil and cultivable land (© Jannes Stolte/NIBIO).

Loss of crop production (No changes were made to the original photo. © Jannes Stolte/NIBIO).

 

Decline in soil structure and productivity (No changes were made to the original photo. © Jannes Stolte/NIBIO).

Off-field:

Pollution of rivers and lakes (Screenshot from  https://njtrees.org/trees-sediment-and-erosion/)

Mudflows (Screenshot from: https://www.bmluk.gv.at/en/topics/forests/forests-and-natural-hazards/what-are-torrents.html)

Damage to infrastructure (Screenshot from: www.railwaygazette.com/infrastructure/infrastructure-managers-assess-impact-of-catastrophic-flooding/59544.article)

Silting of reservoirs (Screenshot from: https://education.nationalgeographic.org/resource/silt/)