Escrito por Soil erosion is, at its core, a natural process. Simply put, it is when topsoil, which is the upper-most layer of the ground, is moved from one spot to another. Why this matters is because topsoil is the part of the land that is highest in organic matter and best suited for farming and other fertile activities, which is why soil erosion can have the greatest impact on farmers and agricultural land.
In other words, soil erosion is a naturally occurring and slow process that refers to the loss of the field’s topsoil by water and wind or through the conversion of natural vegetation to agricultural land.
Essentially, all life depends upon the soil … There can be no life without soil and no soil without life; they have evolved together.
~ Charles Kellogg
When farming activities are carried out, the topsoil is exposed and is often blown away by wind or washed away by rain. When soil erosion occurs, the movement of the detached topsoil is typically facilitated by either a natural process – such as wind or water movement – or by the impact of man, such as through tilling farmland.
The process of soil erosion is made up of three parts:
- Detachment: This is when the topsoil is actually “detached” from the rest of the ground
- Movement: This is when the topsoil is relocated to another area
- Deposition: Where the topsoil ends up after this process
According to Wikipedia,
“Soil erosion is one form of soil degradation. Soil erosion is a naturally occurring process on all land. The agents of soil erosion are water and wind, each contributing a significant amount of soil loss each year.
Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks.”
When it comes to our planet, natural resources are typically affected by two things – either naturally-occurring ones such as weather or from man-made influence.
Soil erosion, or the gradual reduction of topsoil in a geographic area, can be caused by both natural and unnatural processes, but it can also have great effects on inhabitants of an affected area.
One of the major concerns regarding soil erosion is that it can permanently affect the land, which can be devastating for farmers or those with agricultural pursuits.
Unfortunately, many people are still uneducated about soil erosion, which is leading to the occurrence in greater amounts around the world. Soil erosion contributes to pollution in adjacent water sources and reduces cropland productivity.
Major crops that cause soil erosion include coffee, cotton, tea, tobacco, palm oil, soybean, and wheat that can increase soil erosion beyond the soil’s ability to maintain itself.
Types or Forms of Soil Erosion
1. Sheet Erosion
Sheet Erosion by water is almost invisible. Lighter colored soils are a sign that over the years, erosion has taken its toll.
2. Wind Erosion
Wind Erosion is highly visible. Although it is a problem, water erosion is generally much more severe.
3. Rill Erosion
Rill Erosion happens with heavy rains and usually creates small rills over hillsides making farming difficult.
4. Gully Erosion
Gully Erosion occurs when water runoff removes soil along drainage lines and makes gullies; some of them are huge and impossible to cross with farm machinery.
5. Ephemeral Erosion
Ephemeral Erosion usually occurs in natural depressions. It differs from gully erosion that the area can be crossed by farm equipment.
6. Bank Erosion
Bank Erosion refers to the wearing away of the banks of a stream or river. Generally, constructed drainage channels and natural streams act as outlets for subsurface drainage systems and surface water runoff. It is the progressive undercutting, scouring and slumping of these drainage ways.
Various Causes of Soil Erosion
As mentioned, the predominant causes of soil erosion are either related to naturally-occurring events or influenced by the presence of human activity. Some of the principal causes of soil erosion include:
1. Rain and Rainwater Runoff
During heavy rains, soil erosion is common. First of all, the water starts to break down the soil, dispersing the materials it is made of.
Typically, rainwater runoff will impact lighter materials like silt, organic matter, and finer sand particles, but in heavy rainfall, this can also include the larger material components.
2. Farming
When land is worked through crops or other agricultural processes, it reduces the overall structure of the soil, in addition to reducing the levels of organic matter, making it more susceptible to the effects of rain and water.
Tilling in particular, because it often breaks up and softens the structure of the soil, can be a major contributor to erosion. Farming practices that reduce this activity tend to have far fewer issues with soil erosion.
3. The slope of the Land
The physical characteristics of the land can also contribute to soil erosion. Important terrain characteristics for soil erosion are slope gradient, length, aspect and shape.
For example, land with a high hill slope will perpetuate the process of rainwater or runoff saturation in the area, particularly due to the faster movement of the water down a slope.
4. Soil Erodibility
The susceptibility of soil to the erosion is determined by inherent soil properties, e.g., texture, structure, soil organic matter content, clay minerals, exchangeable cautions and water retention and transmission properties.
Soil erodibility estimates the ability of soils to resist erosion, based on the physical characteristics of each soil. The principal characteristic that affects erodibility is texture.
However, organic matter, structure, and permeability also contribute. Soils with faster infiltration rates, higher levels of organic matter, and improved soil structure are usually found to have greater resistance to erosion.
Loam-textured soils, sand, and sandy loam usually tend to be less erodible compared to very fine sand, silt, and certain clay-textured soils.
5. Lack of Vegetation
Plants and crops help maintain the structure of soils, reducing the amount of soil erosion. Areas with less naturally-occurring flora may be a hint that the soil is prone to erosion.
6. Unsheltered Distance
Unsheltered distance with lack of windbreaks such as trees, shrubs, crop residue, etc. make way for the wind to put soil particles into motion for greater distances, thereby increasing soil erosion and abrasion. Knolls and hilltops are usually exposed without any vegetation cover and suffer the most.
7. Wind
Wind can be a major factor in reducing soil quality and promote erosion, particularly if the soil’s structure has already been loosened up. However, lighter winds will typically not cause too much damage, if any.
The most susceptible soil to this type of erosion is sandy or lighter soil that can easily be transported through the air.
Harmful Effects of Soil Erosion
A major problem with soil erosion is that there is no guideline as to how quickly or slowly it will occur. If largely impacted by ongoing weather or climate events, it may be a slow-developing process that is never even noticed.
However, a severe weather occurrence or other experience can contribute to rapid-moving erosion, which can cause great harm to the area and its inhabitants.
Some of the greatest effects of soil erosion include:
1. Loss of Topsoil
Obviously, this is the biggest effect of soil erosion. Because topsoil is so fertile, if it is removed, this can cause serious harm to farmer’s crops or the ability to effectively work their land.
2. Soil Compaction
When the soil under the topsoil becomes compacted and stiff, it reduces the ability for water to infiltrate these deeper levels, keeping runoff at greater levels, which increases the risk of more serious erosion.
3. Reduced Organic and Fertile Matter
As mentioned, removing topsoil that is heavy with organic matter will reduce the ability for the land to regenerate new flora or crops.
When new crops or plants can’t be placed successfully in the area, this perpetuates a cycle of reduced levels of organic nutrients.
4. Poor Drainage
Sometimes too much compaction with sand can lead to an effective crust that seals in the surface layer, making it even harder for water to pass through to deeper layers.
In some ways, this can help erosion because of the densely packed soil, but if it perpetuates greater levels of runoff from rainwater or flooding, it can negatively impact the crucial topsoil.
5. Issues With Plant Reproduction
When soil is eroded in active cropland, wind, in particular, makes lighter soil properties such as new seeds and seedlings to be buried or destroyed. This, in turn, impacts future crop production.
6. Soil Acidity Levels
When the structure of the soil becomes compromised, and organic matter is greatly reduced, there is a higher chance of increased soil acidity, which will significantly impact the ability for plants and crops to grow.
7. Long Term Erosion
Unfortunately, if an area is prone to erosion or has a history of it, it becomes even harder to protect it in the future. The process has already reduced the soil structure and organic matter of the area, meaning that it will be harder to recover in the long run.
8. Water Pollution
A major problem with runoff from soils – particularly those used for agricultural processes – is that there is a greater likelihood that sediment and contamination like the use of fertilizer or pesticide. This can have significant damage on fish and water quality.
9. Climate Change
The fact that erosion degrades land denotes that it can support fewer plants that can help absorb climate-warming CO2. Soils have the ability to potentially sequester enough GHG in a year to equal about 5% of all man-made GHG emissions annually.
A report from the Intergovernmental Panel on Climate Change (IPCC) found that when cultivated without conservation practices, the soil is currently eroding up to 100 times quicker than it’s forming.
There will be even higher risk of erosion in the future because of emissions-triggered temperature changes, with resulting decreases in human health, agricultural production, and land value.
Impressive Solutions to Soil Erosion
When it comes to finding solutions for soil erosion, the most useful techniques found tend to be those that emphasize reinforcing the structure of the soil and reducing processes that affect it.
1. Careful Tilling
Because tilling activity breaks up the structure of the soil, doing less tilling with fewer passes will preserve more of the crucial topsoil.
2. Crop Rotation
Plenty of crop rotation is crucial for keeping land happy and healthy. This allows organic matter to build up, making future plantings more fertile.
3. Increased Structure For Plants
Introducing terraces or other means of stabilizing plant life or even the soil around them can help reduce the chance that the soil loosens and erodes. Boosting areas that are prone to erosion with sturdy plant life can be a great way to stave off future effects.
4. Water Control
For those areas where soil erosion is predominantly caused by water – whether natural or man-made – specialized chutes and runoff pipes can help to direct these water sources away from the susceptible areas, helping stave off excess erosion.
Having these filters in particular areas rather than leading to natural bodies of water is a focus to reduce pollution.
5. Soil Conservation
Soil conservation can be defined as “the combination of the appropriate land use and management practices that promotes the productive and sustainable use of soils and, in the process, minimizes soil erosion and other forms of land degradation.”
Various measures for soil conservation are primarily meant for the prevention of soil loss or reduced fertility caused by acidification, over usage, salinization or other chemical soil contamination.
Different techniques for improved soil conservation involve cover crops, crop rotation, planted windbreaks, and conservation tillage and affect both fertility and erosion.
6. Increased Knowledge
A major factor for preventing soil erosion is educating more and more people who work with the land on why it is a concern, and what they can do to help reduce it.
This means outreach to farmers in susceptible areas for ways that they can help protect crops from inclement weather or ways that they can help make sure their soil remains compact without restricting their plant growing activities.
References:
Soil Erosion Issues
Problems of Soil Deterioration
Global Impact of Soil Erosion by Nature
