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Soil Erosion Problems and Solutions

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Need to Know: Soil Degradation

The soil is a crucial component of agriculture and forestry, and degradation leads to a partial or total decline of its productive capacity. Due to natural hazards or human mismanagement, the soil can lose one or more of its potential ecological functions, leading to a steep decline in its capacity to be used in the production of goods and services.

Defining Soil Degradation

A 2004 report by the U.N. Department of Economic and Social Affairs described soil degradation as a process that occurs when “the balance between the attacking forces of climate and the natural resistance of the terrain against these forces has been broken by human intervention, resulting in a decreased current and/or future capacity of soil to support life”.

Soil degradation is primarily attributed to mismanagement or misuse of the land in domains such as agriculture, industry, or urban planning. Due to its major impact on food growth and consumption and on the environment as a whole, soil degradation causes have been a constant topic of research and concern throughout the 20th and the 21st centuries.

Causes of Soil Degradation

Throughout the world, soil degradation is usually caused by one or more of these three factors:

  • Physical factors represent the loss of the soil’s life-sustaining qualities due to natural physical forces, mainly water or wind erosion. These physical forces affect the structure of the soil mainly by damaging its top layer and subsequent organic matter, where the nutrients necessary for sustaining growth are found. Long-term exposure to massive rainfall, winds, floods, surface runoff, or any other powerful physical factors leads to the slow decline in the respective soil’s structure and quality. According to Volume 11 of the publication “Advances in Soil Science,” physical degradation can include:
    • Compaction and hardsetting, causing densification of soil due to the elimination or reduction of its structural pores, and also increasing soil’s bulk density as a result of natural and manmade factors.
    • Desertification caused by erosion and sedimentation due to constant exposure to wind and water.
    • Laterization, meaning the desiccation and hardening of plinthitic material.
  • Chemical factors are the alterations of the soil’s chemical properties that lead to it losing nutrients. University of Chittagong professor Khan Towhid Osman’s book, “Soil Degradation, Conservation and Remediation,” states that chemical degradation of soil can be caused by a number of factors, such as a rise of alkalinity or acidity levels, or simply the oversaturation of the respective soil with water. The result is usually either a buildup of salt or the hardening of the soil, with soil nutrients being irreversibly lost in the process. More than half a billion acres of land are affected by chemical soil erosion throughout the world. 
  • Biological factors refer to human activities or plant growth that cause degradation of soil quality by accentuation compaction, erosion, water runoff, anaerobiosis, nutrient depletion, reduction in SOC pool etc., as described in the book “Soil Degradation in the United States: Extent, Severity, and Trends.” An overaccumulation of fungi or bacteria can, for example, cause biochemical reactions that will drastically reduce the soil’s capacity to grow proper crops. Poor farming practices and overfarming also have the potential to diminish the fertility of the soil by depleting it of nutrients. These farming practices can be excessive cultivation, improper manuring, misuse or overuse of fertilizers, or excessive irrigation, among others. 

There are also other factors that can lead to soil degradation. Deforestation will dramatically alter the soil’s composition by removing the vegetation that binds it together. Mining and other industrial activities release toxic substances into the soil, making it poisonous and completely unusable. Also, urbanization will unavoidably affect the soil quality by covering the soil with concrete and with the inevitable rise in pollution levels.

Effects of Soil Degradation

The most significant effect of soil degradation is the loss of a land’s life-sustaining qualities. Throughout the world, more and more land becomes unusable because of factors like soil pollution, contamination, and erosion.

The overuse of fertilizers also keeps the affected land from regenerating, polluting both the land and water in the area and dramatically decreasing land value.

Another major effect of degradation to the soil is its contribution to droughts and the occurrence of arid conditions in certain areas. Soil degradation reduces the biodiversity in the area, leading to desertification and the inevitable drought and aridity that come with it.

The University of Sheffield’s Grantham Centre for Sustainable Futures estimates that approximately 40 percent of the world’s agricultural land is unusable because of the loss of soil quality caused by degradation and overuse of agrochemicals. These practices make agriculture impossible, and therefore make the respective land useless.

Due to the alteration of the degraded soil’s physical attributes, one of the consequences is the affected land’s inability to hold massive amounts of water, leading to increased chances of floods occurring.

How Big is the Range of Soil Degradation Observed Between Continents?

Soil degradation is a big issue all over the world, but Africa is by far the most-affected continent. Throughout the African continent, it is estimated that 28 percent of the land is affected by degradation.

This costs the continent as much as 56 billion euros every year. It’s usually manmade, with the lack of fertile land being compensated by mass deforestation, leading to massive soil degradation. It can be reversed, though, with massive state programs and policies that train communities to take better care of the land. 

Other areas of the world gravely affected by the degradation of soil are Southeast Asia, Northern and Central Australia, China, and parts of the boreal forests in North America and Siberia. 

Solutions for Soil Degradation

The reduction and reversal of soil degradation typically lie in the elimination of manmade causes. Chief among these causes is massive deforestation, and the trend can be reversed by educating populations and governments about the dangers of reckless deforestation. Improving the land’s organic composition and restoring its mineral matter can also reverse soil degradation.

Prevention is also crucial to reducing the amount of land that is affected by soil degradation. Reducing over-irrigation, improving overall irrigation efficiency, and preventing land salinization are all significantly more cost-effective than restoring soil that has already been affected by degradation.

Soil degradation is an issue that affects the entire world in numerous ways. It increases the odds of famine and poverty in already impoverished countries. It also increases the cost and human labor that’s necessary to grow food throughout the world, massively influencing the price and quality of the food that we eat.

Other side effects, from dramatic rises in pollution levels to socio-economic effects like mass migration, also contribute to soil degradation’s status as a major global issue.

Sources:

Advances in Soil Science Vol. 11, Soil Degradation

Soil Degradation, Conservation, and Remediation, Khan Towhid Osman

Soil Degradation in the United States: Extent, Severity, and Trends, Rattan Lal, Terry M. Sobiecki, Thomas Iivari, John M. Kimble

Effective Ways to Control Soil Erosion

Erosion can cause devastating damage to your home, property, or construction site, which is why finding an effective way to control erosion is a primary concern for anyone hoping to preserve a landscape or complete a successful build on solid ground.

Before you tackle the erosion itself, however, it’s important to understand the definition of erosion, what causes erosion, what type of erosion you’re dealing with, and how to choose the best method for controlling it.

What Is Erosion?

You were probably introduced to a rudimentary erosion definition as a kid, but how much do you really know about this complex process?

In a nutshell, scientists define erosion as a process by which the surface of the earth gets worn down either by natural elements like ice and wind or by manmade interactions such as poor land management techniques at a faster rate than the soil or rock is formed.

When only natural elements are involved, erosion is generally a slow process that can create massively impressive formations. The Grand Canyon is an extreme example of steady, prolonged erosion.

Other erosion examples include:

  • Caves.
  • Riverbanks.
  • Coastlines.
  • Cracks in rocks.
  • Landslides.

Some of the most devastating types of erosion involve people’s homes and properties. Remember the infamous Dust Bowl of the 1930s?

The Dust Bowl occurred because people moved to the Great Plains and started plowing the land, which was never ideal for farming. After a few short droughts, people mistakenly believed there would be enough rainfall to sustain future crops, so they broke up the prairie soil and destroyed native grasses in order to plant wheat.

Unfortunately, a 10-year drought settled over the prairie which quickly dried up the topsoil. Once all that freshly planted wheat died, there was nothing left to hold the soil in place.

As a result, a series of dust storms swept through and damaged the prairie’s ecology and agriculture. Entire farms were covered with sand and turned to desert. Cattle were found dead with dust coating their stomachs. Residents coughed up clumps of dirt from breathing in dust. The effect was so extensive that dust storms blew Kansas soil all the way to New York City.

To this day, the prairie region hasn’t fully recovered. And the entire event could have been avoided if settlers had accounted for the region’s history of droughts, utilized different farming methods, and not overworked or stripped the land.

Sure, the Dust Bowl is an extreme example of an erode definition, but it’s given us a clearer understanding of the importance of responsible agricultural practices and construction techniques that can help us become better stewards of our environment.

Types of Erosion

Now that you have a better understanding of this natural process, you’re probably wondering what causes erosion? Land erosion happens in a variety of ways, the main ones being:

  • Water Erosion
  • Wind Erosion
  • Glacier Erosion
  • Permafrost Erosion
  • Human Cause Erosion

Water Erosion

Water erosion results from flowing water removing soil material. The soil can be impacted by raindrops, suspended in runoff, or affected by ocean waves. Both the chemicals in the water and the force that make up the flow can break down rocks and change the shape of riverbanks.

There are four types of accelerated water erosion:

  • Sheet erosion, which occurs when soil particles resting on a downslope are impacted and detached by rainwater. The soil detaches in a sheet-like formation that flows overland as a whole piece or uniform layer. Imagine pulling a sheet of sod across the yard and that’s pretty much what sheet erosion looks like. Sheet erosion typically occurs on sites with poorly consolidated soil material, such as a recently plowed field.
  • Rill erosion, which refers to soil removal through cutting or tilling numerous channels where runoff can concentrate, resulting in soil loss and eroded fields.
  • Gully erosion, which results from water cutting into the soil along the flow line, exposing natural drainage-ways, vehicle ruts, animal trails, and crop rows. Common farm equipment cannot cross deep gullies.
  • Tunnel erosion, which is the movement of excess water through a dispersive subsoil such as old root holes, animal burrows, or surface cracks.

Wind Erosion

Although the wind might not be strong in your area, wind can still transfer light objects like pebbles and rocks until they run into landforms. Over time, these tiny particles can start to erode whatever they hit.

Glacier Erosion

Also known as ice erosion, glacier erosion occurs when huge bodies of ice transfer big chunks of rock. The combination of ice, water, and sediment creates one impressive eroding entity.

Permafrost Erosion

In northern areas of the Northern Hemisphere, there is currently an accelerating problem of the permafrost melting, and eroding into lakes and sinkholes. Permafrost is the historically “permanently frozen soil”. The frozen ice is actually a constituent of the soil itself, lending structure and rigidity to the silt-rich soil.

Due to climate change, the ice is melting, leaving a very unstable layer of loamy or silty soil which is carbon-rich and contains ancient microorganisms. As the microorganisms reanimate, they produce gases such as methane, which erupt from the soil and create voids which fill with melted water and quickly form new lakes or sinkholes. The Siberian tundra is currently experiencing this phenomena at an unprecedented rate; primarily due to climate change.

Human Cause Erosion

Soil erosion occurs a number of ways. The most egregious would be human-induced causes. These include construction, faulty farming (tillage), mining, deforestation, overzealous herbicide use, and cattle overgrazing. The usage of herbicides or allowing livestock to overgraze cause ground cover vegetation to die, leaving bare soil. The bare soil is easily eroded away by natural means.

Something as simple as not utilizing appropriate engineering principals or procrastinating with erosion mitigation utilities on ditches or roadways will inevitably lead to natural erosion. The natural causes of soil erosion would include precipitation, wind velocity, soil characteristics, hydrology, and slope gradients. The eroded topsoil will ultimately inundate the planned drain system perhaps leading to enormous damages to surrounding land.

5 Ways to Prevent Erosion

Fortunately, there are effective ways to control erosion. Your specific solution will depend on the factors causing the erosion as well as its severity. Taking these erosion control measures can help minimize construction costs and keep your home safe from harm.

Coir Products

Coir is a type of material made from natural coconut fibers that are ideal for erosion control. Coir erosion products are available in numerous shapes and sizes, including mats, blocks, wattles, logs, and silt checks. They’re so effective, in fact, that coir has been used to control coastal and riverbank erosion. Plus, since they’re all-natural, coir products are a more aesthetically pleasing choice than most erosion prevention measures.

Articulated Concrete Blocks

While not as natural as coir, concrete blocks are available in just as many shapes and sizes. They can even form interconnected grids to prevent erosion on waterway embankments. The biggest downside to articulated concrete blocks, however, is that they look best protecting manmade structures like boat ramps and channels.

Dust Control

Utilizing dust control methods like silt fences and misted water keeps topsoil moist enough to resist dreaded wind erosion.

Riprap

Riprap is a common erosion control method that uses large, interlocking stones as barriers. These structures are mainly placed on unstable slopes with seepage issues that have already eroded.

Soil Nails

One of the more surprising methods of erosion prevention is soil nailing, which involves drilling and placing steel bars deep into the soil and capping them with a facing that creates a retaining wall.

No matter the causes of erosion you’re dealing with, finding the right prevention technique is key. If you’re looking for an environmentally friendly, superior performing, cost effective and affordable option, consider coir-based erosion products.

Sources:

https://www.nps.gov/grca/planyourvisit/upload/life_geology.pdf

https://www.sciencedirect.com/science/article/abs/pii/S1875963715000798

https://www.nda.agric.za/docs/Infopaks/Soilerosion.pdf

https://www.nrdnet.org/sites/default/files/soil_erosion.pdf

https://nptel.ac.in/courses/105101010/downloads/Lecture06.pdf

https://www.erosionpollution.com/Coir.html

https://www.geosolutionsinc.com/products/erosion-control-articulated-concrete-blocks.html

http://lshs.tamu.edu/docs/lshs/end-notes/riprap-2389874252/riprap.pdf

https://www.minovaglobal.com/documents/34900/167120/Minova_Soil_Nailing_Web_EN.pdf/0fb0ca67-ba19-8fba-1850-f2828da26fa1

Introduction to Soil Remediation

When nature and human activities clash, it’s practically inevitable that pollution and toxins contaminate our soil, sediment, groundwater, and surface water. Sadly, soil contamination has serious, long-term effects on property and eco-systems, even resulting in massive animal die-offs.

What Is Contaminated Soil?

Contaminated soil is defined by significant harm to the health of living organisms or interference with ecological systems, which usually involves significant pollution to either the soil itself or nearby water.

Environmental contaminants are not only harmful to nature, but they can also negatively impact human health. In fact, people can get permanently ill from soil contamination.

One high-profile example of environmental contamination that made people sick involved Erin Brockovich, who helped build a case against the Pacific Gas and Electric Company in 1993. PG&E had allegedly allowed hexavalent chromium to contaminate the drinking water in Hinkley, California.

The case was settled in 1996, resulting in the largest settlement ever paid in a direct-action lawsuit in the United States. The incident was the focus of the 2000 film “Erin Brockovich,” starring Julia Roberts.

Given how devastating the effects of environmental contamination can be, remedial action is often necessary to address contaminated soil and water. That’s why numerous regulatory requirements have been legislated over the years, helping maintain standards by which government agencies and environmental remediation services must abide.

What Is Soil Remediation?

Soil remediation is a term applied to various processes used to decontaminate the soil. The goal is to treat contaminated soil by removing and converting pollutants into less harmful products.

Some of the pollutants that soil remediation addresses include:

  • Heavy metals
  • Cyanides
  • Pesticides
  • Creosote
  • Semi-volatiles
  • Petroleum and fuel residues

Removing these pollutants from the soil prevents them from seeping into the groundwater, surface water, agricultural crops, and wild flora. In cases where they’ve already affected water sources, additional land remediation techniques are required.

Types of Soil Remediation

There are four main techniques used for soil remediation, each of which takes a distinct approach to removing pollutants. These techniques are:

  • Thermal Soil Remediation
  • Air Sparging
  • Encapsulation
  • Bioremediation

It’s important to choose the right soil remediation technique for each situation, as each method has an indicated best use.

Thermal Soil Remediation

Thermal soil remediation is an in-situ technique that involves heating contaminated material in a Primary Treatment Unit (PTU) to the point where hydrocarbon impurities and water evaporate. Polluted materials are typically treated at temperatures ranging from 650 to 900 degrees. Think of the PTU as a massive oven that bakes the soil.

Once heated, the materials are transferred from the PTU into a cooling unit such as an auger or mixer. At this point, water is added for additional cooling and dust control. Once cooled, the material is moved from the cooling unit via a conveyor system and is then tested and recycled.

Thermal soil remediation is best used for soil that has been polluted by either contaminated water or hydrocarbon compounds like petroleum products. Since thermal remediation methods are performed without excavating the contaminated zone, they are great for hard-to-access locations such as between buildings and around buried utilities.

Air Sparging

Another soil remediation method is called air sparging, which involves injecting large amounts of air into a contaminated soil stratum to force organic vapors outwards where they can be treated by carbon filtering. Unlike other methods, air sparging has to be applied directly to the soil instead of being used on extracted soil in a treatment unit.

Air sparging is commonly used for removing hydrocarbon pollutants, but it’s best used in cases where the soil can’t be removed from the site.

Encapsulation

Encapsulation is an interesting remediation soil technique because it separates contaminates instead of filtering them. Essentially, encapsulation ensures that the pollutants can’t spread any further than they already have, so it acts similar to a medical quarantine.

The contaminant source is covered with layers of lime, concrete, clay caps, or synthetic textiles that limit precipitation’s infiltration, thereby preventing the leaching and migration of contaminants away from the isolated zone. The process isolates the polluted soil and prevents it from coming into contact with the surrounding soil.

Unfortunately, although the technique is effective, it doesn’t treat and recycle the soil to be used in cultivation. Instead, encapsulated soil will never be used to grow anything ever again, which makes encapsulation a sort of “last resort” technique.

Bioremediation

Bioremediation is a soil remediation technique that uses a biological mechanism rather than mechanical means. The contaminated soil is treated at the site with aerobic and anaerobic bacteria that have been engineered specifically to consume and break down pollutants. Once the contaminate has been taken care of, the microbes die off.

While bioremediation is the most natural technique of soil remediation, it’s most successful when the soil maintains a temperature of 70 degrees with sporadic rainfall to optimize the moisture levels. As such, bioremediation isn’t always possible, especially in extreme climates. In colder climates, the soil must be covered and insulated prior to the bioremediation.

NJDEP Soil Remediation Standards

In 2017, the New Jersey Department of Environmental Protection (NJDEP) updated the residential and non-residential soil remediation standards for 19 contaminants listed in the United States Environmental Protection Agency Integrated Risk Information System database. The updates reflected recent revisions made to existing toxicity data.

Overall, the standards to remediate soil increased (became less stringent) for 11 contaminants and decreased (became more stringent) for six contaminants. One contaminant will no longer be regulated and one remained unchanged.

Of the six contaminants for which the standards become more stringent, three stood out as having their remediation standards decrease by an order of magnitude:

  • 1,1-Biphenyl
  • Cyanide
  • Nitrobenzene

Thallium is the contaminant no longer being regulated by NJDEP soil remediation standards.

How Much Does Soil Remediation Cost?

Historically, soil contamination has had far-reaching economic impacts, but remedial action aims to minimize those adverse effects. Soil remediation costs vary depending on the technique, but the NJDEP has released an estimated soil remediation cost per acre-foot that can provide a glimpse into the economic impacts.

For example, consolidating and covering on-site soil with roads or other structures costs around $1000 to $2000 per acre-foot. Blending contaminated soil with clean soil can cost up to $15,000, while treating soil with innovative treatment technologies can range from $50,000 to $100,000 per acre-foot.

Remediating soil isn’t necessarily easy or cheap, but remediated soil prevents long-term, detrimental effects on our ecosystem. Taking responsibility for man-made contaminants goes a long way toward ensuring a healthy planet for future generations.

Sources:

https://www.nj.gov/dep/srp/guidance/srra/srwmp_implementing.pdf

https://www.nj.gov/dep/special/hpctf/final/costs.htm

https://centerjd.org/system/files/MB08_Enviro2.pdf

http://www.terratherm.com/pdf/white%20papers/paper3-11-6-09.pdf

https://clu-in.org/download/toolkit/sparge_o.pdf

https://pdfs.semanticscholar.org/6bff/82c2c20de69c1892915f4ee46f60f50c5f2a.pdf

A Guide to Soil Erosion and Prevention

Soil erosion is a kind of soil degradation that occurs naturally on all land. However, it is usually heavily influenced by human activity. Soil erosion’s natural causes are typically similar to the causes for other types of erosion: mainly water, wind, ice, and gravity.

The most devastating effects of soil erosion are the degradation of fertile land and water pollution and all the negative effects that come with them. For these reasons, learning how to prevent soil erosion is crucial for any community.

Causes of Soil Erosion

The first step in reducing soil erosion is to properly understand the causes behind it. It is usually caused by several factors working together, both natural and man-made. It is difficult to pinpoint the exact causes for each situation, so all potential factors have to be taken into consideration.

Usually, the natural causes of soil erosion cannot be fully eliminated, only contained. One cause of soil damage is from the massive amounts of water dropped by heavy rains. This deluge sweeps away the top part of the soil, which contains important nutrients, thus decreasing the quality of the soil. Wind is another major natural cause of erosion, as it tends to lift and transport light and sandy soils, decreasing land quality.

The most significant man-made factor of soil erosion is heavy farming. Overworking the land for long periods of time will greatly affect the land’s structure and deplete it of nutrients. Tilling especially damages the soil. So how does no-till farming reduce soil erosion? It does so simply by keeping a constant land structure. Vegetation is, however, needed to avoid soil erosion, so a complete lack of plants and crops is also a contributing factor, as is the deforestation of a piece of land. In his book, “The Political Economy of Soil Erosion in Developing Countries,” geographer and environmentalist Piers Blaikie argues that most man-made factors of soil erosion are caused by mismanagement and lack of funds in developing countries.

Soil Erosion Solutions

Soil erosion prevention is vital for the well-being of a community and can be achieved by following a series of steps. Most ways of preventing soil erosion rely on eliminating the causes or limiting the natural events that lead to the erosion of land. Prevention is done with the help of ecotechnology, which is using technology and knowledge to better manage human interaction with nature.

The lack of vegetation on a piece of land is a major cause of soil erosion, as factors such as heavy rains or strong winds will do significantly more damage to bare soil. That is why using plants to prevent soil erosion is an efficient move. Vegetation not only keeps the soil in place, thanks to the plants’ roots, but also provides the soil with valuable nutrients from fallen leaves, fruit, or animal droppings. The result is a portion of land that is able to withstand the effects of wind and water, therefore preventing degradation.

For areas in which planting vegetation is not an option or is only in the initial phases, adding rocks and mulch is a good way of controlling soil erosion. The effects are similar to those that come from vegetation, meaning the soil will be heavier and less likely to be displaced by rain or wind. Keeping a fertile topsoil means that plants will start to grow, even from beneath the rocks or mulch, further strengthening the land.

Steep slopes present extra challenges for preventing soil erosion, as another natural factor, gravity, joins rain and wind in causing damage. In this case, the solution is to use a soil erosion mat, which is basically a nonbiodegradable soil erosion control blanket that is placed over the seeds or young plants. This blanket holds the top part of the soil in place, even when it is threatened by multiple natural causes of erosion. If soil erosion mats can’t keep massive amounts of water from carrying mud downhill, putting down fiber logs will block the water and keep it on the soil.

Properly draining water from the soil is another major part of fixing soil erosion. If the land is not properly drained, it will only take a heavy rainfall for water to build up and wash away nutrient-rich topsoil. Watering of plants must be kept to a minimum and constantly adjusted, depending on the amount of rain that falls in a particular period of time. Ideally, irrigation and underground drainage systems will be put in place for efficient water management.

Among the soil erosion prevention techniques, avoiding soil compaction is one of the most important. The constant movement of people, cattle, or machines on a particular piece of land will press down the soil, making it harder and denser. Since compacting reduces space between dirt particles, water is not able to drain through; instead, it carries the soil downhill. Compacted soil also makes it harder for plants to push through, reducing the vegetation needed for healthy soil. Creating walking paths and keeping machines and cattle off the land will help to prevent soil erosion.

How Does Terracing Prevent Soil Erosion?

Terracing is a very effective method to stop soil erosion on sloped plains. Basically, it means cutting the sloped land and forming many receding flat surfaces that resemble steps. Historically, terracing has been used with great success throughout the world and is still used today, mostly in Southeast Asia, the Mediterranean, Africa, and South America. It also is used on islands with steep slopes and allows farming in places that would not have been accessible otherwise.

The reasons for why terracing works are mostly related to the flow of the water that comes from rains. First, the speed at which the water circulates downhill is greatly reduced, preventing it from taking off the top part of the soil. Another upside is that since the water travels more slowly, more of it will be absorbed by the land. This feeds the plants and prevents downhill floods. However, for terracing to work, the system has to be not only well-designed but also properly managed. According to the book, “Terracing for Soil and Water Conservation” by Claude L. Hamilton, inadequate tillage practices or overcropping can make terraces fail only a few years after they have been put to use.

Soil erosion is and has always been a major problem for humanity. Damaged land will not only prevent the growth of rich crops but will also enable other natural calamities, such as major floods caused by the land not absorbing the water. Although soil erosion is partly inevitable due to its natural causes, good farming practices and soil management techniques will help control and prevent it.

List of sources:

The Political Economy of Soil Erosion in Developing Countries, Piers Blaikie

Terracing for Soil and Water Conservation, Claude L. Hamilton