Effective Strategies for Erosion Control

Erosion is a natural process that is seldom understood by the majority of the population. On a per-acre basis, erosion moves almost five tons of soil per year, per acre, in the United States. On a country-wide level, this is about 1.7 billion tons moved by water and wind alone. This has a massively detrimental impact on farmland, with billions being lost to erosion every year.

While admittedly a natural process, climate change has only exacerbated the rate of erosion. This is due to increased rain, which is a direct consequence of global warming. These days, storms are stronger, and the resulting floods are causing entire crops to be lost.

Due to the higher incidence of soil erosion, it’s essential that those with arable land engage in erosion control to protect against the economic and environmental impact of this phenomenon. This guide will explore some effective strategies for controlling soil erosion.

Understanding Erosion

Soil erosion is the process of silt and soil being worn or washed away from the ground over an extended period of time. Rain and wind are often the causes of soil erosion. However, when land is farmed or trees are cleared, the soil becomes more vulnerable to erosion. Several other types of erosion also significantly change the land.

Water Erosion

Different types of water erosion can occur, depending on the location of the soil and whether it is hit by rain or covered by a body of water.

Types of water erosion include:

Splash erosion: This is when the soil is affected by rainwater. When rain hits the ground, it can spatter with a strong impact that splashes the soil up to 2 feet.
Sheet erosion: This is often the result of a heavy downpour. Runoff that does not soak into the ground will run along the surface, taking dirt with it.
Streambank erosion: Streams cause this type of erosion. As the water runs downstream, the soil along the sides gets pulled into the water.
Gully erosion: Gullies are the formation of deep crevasses along a river. When it rains, these carved valleys fill with water. During a dry period, they do not contain any water.
Coastal erosion: When an ocean causes the soil to wear away, this is called coastal erosion. This is often caused by waves, tides, and fierce storms along the coast.

Wind Erosion

Wind erosion occurs when the wind is strong enough to move the soil. With enough wind, the topsoil is removed over time. Wind erosion is common in deserts and occurs often in areas with less rain.

Types of wind erosion include:

Surface creep: This is when the wind slightly moves relatively large particles that are up to 2 millimeters along the surface.
Saltation: This is when the wind bounces small particles, typically less than half a millimeter, along the ground.
Suspension: Tiny particles that create dust are part of this type. The particles can go higher in the air and reduce visibility.

Glacial Erosion

Glaciers move, and when they do this, they take everything with them, including soil. With enough time, glaciers can carve out deep valleys in the mountains and form unique landmarks. Cape Cod has a distinct fish hook shape because it was formed by a glacier.

Unchecked Erosion Consequences

If left unchecked, erosion has a number of consequences that will affect the world we live in. It is important to know these consequences and find ways to prevent them. Some of the main issues you will find include:

Loss of fertile land: When the land is less fertile, the crop yield is also reduced. The United States suffers an annual loss of over 8 billion dollars because soil fertility has decreased.
Water pollution: The soil that enters the water via erosion may contain contaminants that pollute the river or stream. Fertilizers, pesticides, and other chemicals disrupt the delicate balance of an aquatic population, harming fish and other wildlife.
Habitat destruction: With the loss of crops and polluted water, the habitat will go downhill as well. Animals that rely on the food and water in these habitats face a massive threat.
Infrastructure damage: When soil around a foundation erodes, the structural stability of the building is vulnerable. Cracks form, and with erosion, structural collapses could occur.

Vegetative Erosion Control Methods

As covered previously, tree removal through processes like logging is a direct cause of erosion. Tree roots anchor the soil, so when they are removed, the topsoil becomes much looser and more vulnerable. This type of erosion is exacerbated when trees are removed because the canopy provides an active barrier against wind.

Grass and Ground Cover

By planting trees, grasses, and shrubs, you restore the protective root systems that actively guard against erosion. Like naturally occurring trees that may be reduced by excessive logging, these plants also provide a canopy that protects against rain and wind, which are almost always the primary culprits in erosion. New vegetation has the knock-on effect of slowing runoff; when vegetation prevents topsoil from running off, sheet erosion is naturally curtailed.

In the U.S., native grasses are amazing for preventing soil erosion. This is because these plants have fibrous root systems that are particularly good at keeping soil packed tight and protected against both wind and rain. Some particularly useful grass species include:

Red fescue
Blue fescue
Sedge
Canada wild rye
Buffalo grass
Red switch grass

Cover Crops

Cover crops are an effective vegetative erosion prevention method as well. These crops work in tandem with cash crops by protecting the soil better from erosion than cash crops can. These aren’t harvested for their financial value or edibility but deliver utility.

Like the aforementioned grasses and plants, crops like vetch, cereal rye, winter wheat, and white clover have several useful traits for cash crops. For example, vetch vines effectively cover the ground, protecting it from wind and rain. Similarly, plants like cereal rye and winter wheat have extensive root systems that deliver a layer of protection for the soil.

Tree Planting and Vegetative Buffers

When attempting this kind of erosion control, it’s best to use native species to help keep the topsoil in place. Invasive tree and shrub species have become a problem, as land is frequently lost to this kind of vegetation.This causes negative economic and environmental impacts, and there are plenty of local vegetation choices.

Some non-invasive tree and shrub species to consider are:

Northern bayberry
Forsythia
Periwinkle
Creeping junipers
Northern sea oats
Catmint
Creeping phlox
Smooth hydrangea

Most of these species provide direct barriers via their canopies and have strong root systems to prevent soil erosion. Many can also be used as riparian buffers along waterways. These are vegetative areas where planted trees actively reduce the impact of flooding. These buffer zones work like cover crops to protect farmed land from rising water levels.

Structural Erosion Control Measures

This kind of erosion control uses physical structures, such as retaining walls and concrete channels, to manage erosion. These structures deliver a purely physical barrier to keep wind and rain from negatively affecting topsoil.

Retaining Walls

With slope erosion, wind and water erode soil that’s on a slope or hillside. Retaining walls prevent this kind of erosion by holding the soil behind it. These can be made up of concrete blocks, treated timbers, rocks, boulders, or poured concrete. A wall of this type effectively blocks erosion and works like an earth dam. The wall’s strength and weight must be stronger than the pressure on both sides. They are stronger because they “lean in” to the force of the soil.

Sediment Barriers and Silt Fences

These temporary solutions, known as sediment barriers and silt fences, slow down water flow and trap sediment before they reach bodies of water. This barrier is used at the foot of a slope, and it will retain the silt so that it doesn’t reach unprotected areas. This barrier “ponds” stormwater so that the silt is retained in the porous material of the fence.

Check Dams and Flow Diversion

Check dams, which are temporary structures typically made up of rock, sandbags, or gravel, reduce the slope of a channel. Slowing water flow velocity actively reduces erosion. This can even help soil fertility, as water is retained on the surface without soil loss being an issue.

Other flow diversion structures are similar, except they actively divert water away from the erodible soil. This sends water to places like treatment facilities.

Land Management Practices

Outside of vegetative erosion control, there are centuries-old techniques that you can use to manage erosion. Let’s consider a few.

Contour Farming

Contour plowing is a method of plowing in hilly terrain that involves plowing along the land’s contours. This is the opposite of plowing in straight lines, and it reduces erosion by slowing water runoff. The plowed furrows work as miniature barriers to the water, so topsoil does not wash away during rain storms. This helps the soil retain water without erosion.

Terracing

Also known as terrace farming, this is an erosion-resistant land management practice that creates “terraces” of crops on steep slopes and hills. This methodology is commonly used in Asia to help yield rice crops.

This method is useful for hilly terrains because it allows for the collection of water while also preventing the water from eroding the soil. Since crops are terraced, water flows from one level to the next by design. This keeps certain areas dry and others wet as needed.

Mulching

Mulch is typically organic matter placed on the soil surface to prevent erosion. It conserves soil moisture and enhances soil fertility. When applied to exposed soil on slopes, mulch helps form a micro barrier against flowing water and wind. Wood chips, wheat cloth, or fiber cloth are often used, but inorganic mulching materials are also available.

Effectively, this means you’re using non-decomposing materials for mulching, like rocks, gravel, or plastic sheeting. Since these don’t compose, they provide a longer-lasting barrier against erosion that will stabilize even sloped areas.

Grazing Management

If your animals’ grazing isn’t managed correctly, it can be a major source of erosion. Livestock animals will overgraze and reduce plant numbers, which reduces the root systems needed to keep soil in place. This can even lead to the appearance of invasive species on your grazeable lands.

Instead of using the same area for grazing, consider rotational grazing. This allows the land to recover and grow new plant species. You simply move your animals from one blocked-off section of land to another.

Conclusion

Effective erosion control is essential. Soil erosion in sections of the country, like the Midwest, is causing the loss of arable land at a rate that’s anywhere between 10 and 1,000 times faster than it forms. If you own land, implement at least some of the techniques we outlined to protect your crops and prevent flooding.

Techniques like contour plowing and terracing use fairly natural methods to utilize the sources of erosion to provide crops with additional moisture, making them useful tools on the community level.

As erosion control techniques advance, expect to see more optimized land planning methodologies. New technologies, like drones, will start to be implemented for visualizing new control areas. These AI-powered machines will be able to more accurately analyze areas where there is a risk for erosion to implement sustainable techniques.