Soil erosion is a gradual process of movement and transport of the upper layer of soil (topsoil) by different agents – particularly water, wind, and mass movement – causing its deterioration in the long term.
In other words, soil erosion is the removal of the most fertile top layer of soil through water, wind and tillage.
Soil erosion is a complex process that depends on soil properties, ground slope, vegetation, and rainfall amount and intensity. Modifications in land use are one of the most impactful ways of accelerating soil erosion. These changes then have a cascade effect as the loss of fertile topsoil cover sends millions of tons of sediments into lakes and reservoirs. Changing ecosystems and impacting agricultural production and water quality. There are 5 main types of natural soil erosion:
1) Sheet erosion by water;
2) Wind erosion;
3) Rill erosion – happens with heavy rains and usually creates smalls rills over hillsides;
4) Gully erosion – when water runoff removes soil along drainage lines
5) Ephemeral erosion that occurs in natural depressions.
In this post, Pritish Kumar Halder discussed the main causes and the overall impact of soil erosion. Also about how we prevent soil erosion
The Main Causes and Impacts of Soil Erosion
The most effective way of minimizing erosion is to guarantee a permanent surface cover on the soil surface. Such as trees, pasture, or meadow. However, compared to original forest soils, soils in pasture fields and croplands have less capacity to hold up and are more susceptible to erosion. These soils also have less capacity to absorb water. Which makes flooding more common.
1. Deforestation for Agriculture Is One of the Top Causes of Soil Erosion
The increasingly high demand of a growing population for commodities such as coffee, soybean, palm oil or wheat is clearing land for agriculture. Unfortunately, clearing autochthonous trees and replacing them with new tree crops. That don’t necessarily hold onto the soil increases the risks of soil erosion. With time, as topsoil (the most nutrient-rich part of the soil) is lost, putting agriculture under threat.
2. Soil Erosion is Also Caused by Overgrazing, Which Causes Floods too
Overgrazing is caused by intensive cattle raising. As plants don’t have the recovery period they need, they end up being crushed and compacted by cattle. In this process, topsoil sediments are transported elsewhere. As for the remaining soil, it can lose its infiltration capacity. Which means more water getting lost from the ecosystem and a harder time for new plants to grow.
3. Agrochemicals Cause Soil Erosion and Degradation
The use of chemicals under the form of pesticides and fertilizers on (often) monocultural crops is a very usual way of helping farmers improve their yields. However, the excessive use of phosphoric chemicals ends up causing an imbalance of microorganisms in the soil moisture. Stimulating the growth of harmful bacteria. As the soil gets degraded, the risk of erosion increases and the sediments sweep (via the actions of water and wind) into rivers and nearby regions, possibly contaminating nearby ecosystems.
At the same time, tillage techniques (that turn over crops and forages) commonly used by farmers to prepare seedbeds by incorporating manure and fertilizers. Leveling the soil and taking out invasive seeds also have a large impact. Because it fractures the soil’s structure, tillage ends up accelerating surface runoff and soil erosion.
4. Construction and Recreational Activities
Setting up buildings and roads also have their share of responsibility when it comes to soil erosion as they don’t allow for the normal circulation of water. Instead, it runs off to flood nearby lands, speeded up erosion in these areas. Moreover, motor-based activities such as motocross also have the potential to disturb ecosystems and erode the soil.
Why Preventing and Stopping Soil Erosion is so Important
- Soils help fight and adapt to climate change by collecting and storing carbon and reducing greenhouse gas emissions (GHG) in the atmosphere.
- Resilient soils allow for water infiltration through the soil, filtering pollutants and preventing them from leaching into the groundwater.
- Soils capture and store water for crops, whereas degraded soils retain less water.
- Reducing surface evaporation and increasing water use efficiency and productivity are also processes enhanced by healthy soils.
- Soils are home to 1/4 of biodiversity and they are a key part of the global cycles that make all life possible.
- Soils provide fiber, fuel, medicinal products, and other ecosystem services.
How to Prevent Soil Erosion
Despite the fact human activities have accelerated soil erosion. There are ways of repairing the damage we have created. From reforestation and windbreaks to stone walls or more sustainable agriculture techniques.
1. Stopping Soil Erosion via Sustainable Farming Practices
Regenerative agriculture techniques have the potential to preserve and restore ecosystems and habitats and improve the quality and health of the soil.
2. Protecting the Soil by Planting Windbreaks
Windbreaks are linear plantings of shrubs and trees with the goal of improving crop production, protect the soil, people, and livestock. Windbreaks can reduce wind velocities for a distance approximately 15 times the height of the tallest trees. As a result, there is a lower rate of soil loss across large crop areas.
3. Stone Walls to Prevent Soil Erosion
The sediments accumulating behind the dry-stone walls create suitable land for farming and prevent soil erosion.
4. Reforestation Helps Protect Soils
Reforestation helps reduce sedimentation rates in downstream valleys. According to this UN agency, reforestation on unstable land and around water regions such as rivers increases the water. Retention capacity of land and improve water quality, both of which benefit food production. Moreover, reforestation also has a tremendous potential to help fight climate change as trees capture huge amounts of CO2.
5. Conservation Tillage and Soil Erosion
Conservation tillage stands for as any form of tillage that minimizes the number of tillage passes. These techniques have the potential to reduce the vertical movements of soil. In this way, more crop residues are left on the soil surface reducing the exposure to water or wind erosion.