Land and soil are some of the most important resources we have on earth.
So, it’s important to learn how land/soil is being used, degraded, and conserved/protected.
Land degradation is the blanket term usually used to describe a number of land and soil degradation issues such as soil contamination, soil erosion, desertification, and more.
In this guide, we look at what land degradation is in it’s entirety, along with the causes, the effects/impacts, and the potential solutions to prevent it.
Summary – Land & Soil Degradation
- Land and soil degradation can take many forms – up to 36 types exist
- This is an issue as we rely on soil and land to live on, produce our food, make our clothes, support plant and animal life, plus other important things
- Some of the major types include soil erosion, soil contamination, desertification, soil acidification, soil salinity
- Some of the major causes include wind and water weathering of soil, deforestation and clearing of land, intensive or unsustainable agricultural practices, mining, urbanization and human development, carrying of contaminants by air and water, leaching and run off of contaminants, improper management/disposal of waste, natural or severe weather events, indirect factors, and human population growth
- Degradation of the world’s arable land and top soil are becoming significant issues – it’s estimated we may only have 60 years worth of harvests in top soil left in some countries
- Some solutions to land degradation might include more sustainable farming practices, reducing deforestation rates and planting more trees and plant life, examining our diets to eat more sustainably produced foods, more sustainable mining practices, ensure landfills are properly sealed, monitor industrial waste and dispose of it properly, limit run off from highways and roads, limit water pollution, limit air pollution, fund large projects to restore damaged and degraded soil and land
First, How Do We Use Land On Earth?
Before we look at how land is being degraded, it’s a good idea to get an overall idea of what we generally use land for on earth.
Land types and usage might be divided into:
- Forest land, scrub land, desert and uninhabited land
- Agricultural – pasture, and crop land
- Urban land use – Recreational (parks), Transport (roads, railways), Residential (housing), Commercial/Industrial (business),
- Special Use land, Miscellaneous Use land
The US Department of Agriculture has identified six major types of land use in the US. Acreage statistics for each type of land use in the contiguous 48 states in 2017 were as follows:
- Pasture/range: 654 M
- Forest: 538.6 M
- Cropland: 391.5 M
- Special use: 168.8 M
- Miscellaneous: 68.9 M
- Urban: 69.4 M
What Is Land Degradation?
Land degradation is a very broad term used to describe a range of land degradation forms, with soil erosion, soil contamination, desertification, and soil acidification being some of the major ones.
Land degradation usually has a few elements:
- Damage or change to land or soil which can be physical/mechanical (caused by physical actions) or chemical (caused by a synthetic or hazardous chemical – like pesticides), and caused by humans (such as farmers) or a natural factor (such as weather)
- Results in reduced potential for, or complete loss of, the land being used for any number of land uses – farming/growing food, urban development, biodiversity and ecosystems for animals and plant life etc (this includes deforestation and clearing of rangelands that contribute positively to the ecosystem). The value of the land for humans, animals, plant/vegetation and organisms is lessened as a result of land degradation. As an example, the land’s potential for food production, for building biodiversity, for urban development – is lessened.
Land degradation can be direct (where land or soil is directly damaged), or it can be indirect (where for example contaminated water leaches from it’s source onto a land/soil source)
Something that is interesting to note is that what is land degradation to some, may not be to others. For example, an environmentalist or scientist may look at the environmental aspects of how farmed land is being used, whereas a farmer might look at the economic aspect of what that land can provide.
Types Of Land Degradation
There can be many types of land degradation.
Some of the major types are:
- Soil Erosion – (wind erosion, water erosion, mechanical erosion and so on)
A partial or complete loss of the top fertile layer of soil (the soil layer with minerals and organic matter in it). Arable land in particular has fertile soil used to grow crops.
- Soil Contamination – (chemical contamination by fertilizers, pesticides and herbicides, hazardous waste from industry & residential sectors etc.)
When the chemical properties of the soil and land are changed and contaminated.
- Desertification – (land degradation in arid/dry zone areas)
When soil loses all it’s water and green matter. In this case, it’s very hard to restore the land.
- Soil Acidification – (a reduction in the pH of soil)
When the soil becomes too acidic, it loses it’s productivity. It can be caused by soil amendments, acid rain, nitrogen emissions in the air, and other factors.
- Soil Salinity – (an increase in the salt content of the soil)
When the soil becomes to saline, it loses it’s productivity. It can be caused by ocean environments, over irrigation, water sources with salinity issues, and other factors.
But, there are others – up to around 36 types of land degradation in total.
Land pollution is another name used to describe land degradation.
Causes & Sources Of Land Degradation
There are different causes for the different types/forms of land degradation, and causes may differ from one country or state/province to another (depending on factors like agricultural practices, other environmental pollution factors and so on). For example, the causes of land degradation in one part of Australia might be different to the causes in one part of Africa.
Beyond the specific causes of land degradation, the general causes of land degradation are usually either physical or chemical, or both.
Additionally, they can be natural causes, or they can be human causes.
Soil erosion fore example happens via wind, and water from rain – which are natural causes. But, it can also happen from deforestation, over-cultivation and over-grazing and other human causes.
Another example is soil contamination. This is primarily a human caused land degradation issue, with agricultural chemicals and industrial chemicals being big chemical contaminants.
Waste disposal, mining, urbanization, agricultural chemicals, atmospheric deposition, soil erosion might be seen as the major causes of land degradation.
More specifically, the causes of land degradation overall might be:
- Wind and Water Weathering Of Soil – naturally removes small amounts of the top soil from farming land
- Deforestation, Logging & Clearing Of Land – usually for conversion of land to agricultural land. The ground cover is cleared, exposing the top soil or removing the top soil completely. Biodiversity is also degraded with the clearing of ecosystems and organic matter.
- Intensive Or Unsustainable Farming Practices, Or Mismanaging Land – overgrazing, over tillage, over fertilizing (nitrogen can become excessive), over application of pesticide and herbicide, over irrigation or improper irrigation, and other factors. Additionally, farmers might not set up land conservation practices like ground cover and soil/water drains that can maintain land and top soil.
- Mining – excavation, and mining waste and tailings can cause contamination and degradation
- Urbanisation, & Human Development – development of cities, towns, infrastructure, roads etc. involves the clearing of green land and soil.
- Atmospheric Deposition, & Leaching Of Chemicals – leaching of chemicals or carrying of chemicals (by wind, water etc.) from one location to another where land/soil becomes contaminated or degraded. For example, pesticides can be carried in the air from one place to another. Oil can also leach from roads and major highways into land and water sources .
- Improper Management/Disposal Of Hazardous Chemicals – from households, factories, gas stations. Can cause soil contamination. Radioactive waste from nuclear plants are another example of this.
- Improper Management/Disposal Of Waste – hard waste, water waste, human sewage and so on. Can cause soil contamination and land pollution. Mismanaged landfills are another example of this – where leachate can leak out.
- Natural Or Severe Weather Events – floods, hurricanes and other events
- Indirect Factors – climate change, air pollution, water pollution and other factors
- Human Population Growth – puts pressure on land and soil through increased and more intense food production, increase urbanisation, increased water and air pollution, more waste produced and so on
You can see a good visualisation of soil contamination and how it might be caused here:
– visual.ly, and metropolitantransferstation.com.au
There’s a difference between the causes of erosion on open land and agricultural land:
- The basic factors causing soil erosion-induced degradation are wind and water erosion. Acidification, compaction and salinization are some other causes of agricultural land degradation.
- The main causes of erosion on agricultural land are intensive cultivation, overgrazing, poor management of arable soils and deforestation.
- The causes of soil destruction include chemical-heavy farming techniques, deforestation which increases erosion, and global warming. [more severe weather events like droughts can deprive soil of moisture]
Causes of soil contamination:
- Soil contamination in particular might be caused by Oil spills, Mining and activities by other heavy industries, Acid rain, Agrochemicals, such as pesticides, herbicides and fertilizers, Industrial accidents, Road debris, Drainage of contaminated surface water into the soil, Ammunitions, chemical agents, and other agents of war, Waste disposal of Oil and fuel dumping, Nuclear wastes, Direct discharge of industrial wastes to the soil, Discharge of sewage, Landfill and illegal dumping, Coal ash and Electronic waste.
- The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead, and other heavy metals.
- Any activity that leads to other forms of soil degradation (erosion, compaction, etc.) may indirectly worsen the contamination effects in that soil remediation becomes more tedious.
Some stats on the causes of land degradation are:
- Deforestation accounts for the major land degradation problem as it results in severe soil erosion, flood, and loss of fertile soil.
- Land degradation is caused by soil water erosion (46%), wind erosion (36%), loss of nutrients (9%), physical deterioration (4%), and salinization (3%).
- Overgrazing (49%) followed by agricultural activities (24%), deforestation (14%), and overexploitation of vegetative cover (13%) are the primary causes of land degradation in rural areas
TheGuardian.com has this to say about the causes of land degradation, particularly outlining industrial agriculture as a major cause of land degradation:
- urbanisation, climate change, erosion and forest loss [are all causes of land degradation]. But the biggest factor is the expansion of industrial farming.
- Heavy tilling, multiple harvests and abundant use of agrochemicals have increased yields at the expense of long-term sustainability. In the past 20 years, agricultural production has increased threefold and the amount of irrigated land has doubled … Over time, however, this diminishes fertility and can lead to abandonment of land and ultimately desertification.
- … decreasing productivity can be observed on 20% of the world’s cropland, 16% of forest land, 19% of grassland, and 27% of rangeland.
- High levels of food consumption in wealthy countries such as the UK are also a major driver of soil degradation overseas.
- So, high levels of food consumption, high levels of meat consumption, poor land regulation and poor farming efficiency can compound land degradation effects
- There are six major causes of land degradation in the region: deforestation, shortage of land due to increased populations, poor land use, insecure land tenure, inappropriate land management practices and poverty.
- Water and wind erosion are the major problems but salinity, sodicity and alkalinity are also widespread; water tables have been over-exploited; soil fertility has been reduced; and where mangrove forest has been cleared for aquaculture or urban expansion, coastal erosion has been a common result.
- Finally, urban expansion has become a major form of land degradation, removing large areas of the best agricultural land from production.
- The effect of these forms of land degradation on cereal production has so far been masked by the increasing levels of agricultural inputs that are used. However, production of other crops, such as pulses, roots and tubers, has now begun to decline. It is no coincidence that these crops arc grown on land with low production potential, where rates of land degradation are highest.
Read more about land degradation causes in different parts of the world at:
- https://www.fewresources.org/soil-science-and-society-were-running-out-of-dirt.html (major causes of land degradation, but also soil loss cause by region of the world – we see in Africa overgrazing is the major cause, but in North America it’s agricultural practices)
- https://www.ommegaonline.org/article-details/Restoration-of-Degraded-Agricultural-Land-A-Review/1928 (causes in developing countries)
How Much Of An Issue Is Land Degradation? – Where Is It Happening, & To What Extent? (Stats On Land Degradation)
As noted above with causes, land degradation is happening to different extent in different countries and states/provinces.
Land degradation has been a more significant issue in developing countries than developed countries. But, it’s becoming more of an issue now in developed countries too.
What should also be noted about land degradation is that it is harder for us to see with our naked eye – you can see some signs of things like erosion and desertification, but you can’t see what is happening underground or what chemicals are in the ground, or the quality or thickness of fertile soil.
For these reasons, people may not think land degradation is as big of an issue as it really is.
Some stats on the extent of land degradation and where it is happening (worldwide and country specific) are:
- It is estimated that up to 40% of the world’s agricultural land is seriously degraded.
- It is estimated that today, 33 percent of land is moderately to highly degraded due to the erosion, salinization, compaction, acidification and chemical pollution of soils.
- Soils play a key role in absorbing carbon and filtering water, the FAO reported. Soil destruction creates a vicious cycle, in which less carbon is stored, the world gets hotter, and the land is further degraded.
- One-third to half of the world’s agricultural land was in a degraded state in 2010, and a quarter was severely degraded …
- Even as pressure grows to boost agricultural production, another 12 million ha are lost each year due to poor soil and water management and other unsustainable farming practices …
- The United Nations estimates that degradation of agricultural landscapes cost US$40 billion worldwide in 2014, not counting the hidden costs of increased fertiliser use and the loss of biodiversity and of unique landscapes …
- Land degradation is already one of the major problems affecting the world
- Global rates of soil erosion have been exceeding those of new soil formation by 10- and 20-fold on most continents of the world in the last few decades.
- Currently some 6–7 million hectares are lost annually through soil erosion
- Desertification affects about one-sixth of the world’s population and one-quarter of the world’s land
- Salinization affects some 20 million hectares of irrigated land.
- Land degradation through damage to the soil is a serious problem and its causes are often complex and interwoven. Severe damage has already been done to the world’s soils, and the impact of climate change needs to be considered in parallel with the effect of the existing pressures on the land. It is difficult to separate the effects of these various impacts and their cumulative impact on soils is often greater than a simple summation.
- The UNDP estimated that $42 billion in income and 6 million ha of productive land are lost every year due to land degradation
- A third of the planet’s land is severely degraded and fertile soil is being lost at the rate of 24bn tonnes a year
- The impacts [of land degradation] vary enormously from region to region.
- Worst affected is sub-Saharan Africa, but poor land management in Europe also accounts for an estimated 970m tonnes of soil loss from erosion each year with impacts not just on food production but biodiversity, carbon loss and disaster resilience.
- … sub-Saharan Africa, south Asia, the Middle East and north Africa will face the greatest challenges [in the future] unless the world sees lower levels of meat consumption, better land regulation and improved farming efficiency.
- America’s farms have lost about half their soil organic matter since colonial days
- Of the 80 countries substantially affected by land degradation, 36 are situated in Africa.
- In Lesotho, for example, over 100 km2 (approximately 2% of the total land area) has been degraded due to overgrazing and incorrect farming practices, as well as mismanagement of rangeland and residues from chemicals/pesticides
– apps.who.int (World Health Organisation)
- In the Philippines, for example, it is estimated that soil erosion carries away a volume of soil equivalent to one metre deep over 200 000 hectares every year. In India, some 144 million hectares of land are affected by either wind or water erosion. In Pakistan, 8.1 million hectares of land have been lost to wind erosion and 7.4 million hectares to water erosion.
More resources that outline where land degradation takes place in the world, and stats on how much land degradation and erosion is happening can be found at:
Effects & Impact Of Land Degradation
We have a growing population of people on earth.
As mentioned above, land and soil are resources that we use to not only regulate the environment, but use to extract or produce other resources for that growing population of people.
We will need more production or better efficiency in the future from out land resources, not less.
We use land to:
- Grow food, grow fibres, raise livestock
- Develop housing, commercial buildings and factories, build roads and other infrastructure
- Mine minerals, metals and fossil fuels
- Manage our waste (landfills)
- Contain freshwater sources
- Support living organisms, animals, plants/vegetation and ecosystems
- + more
Land degradation has an impact on:
- Our ability to make money and support an economy
- Our ability to produce or protect vital resources like food and water
- Animals and the environment
- Our health and well being (when we talk about soil contamination and cross contamination of water sources)
What is very clear is that land degradation, through loss of efficiency, loss of production and through increased health and other risks – impacts the short and long term future of the social, economic and environmental aspects of society.
Soil erosion and other land degradation issues lead to soil that is less able to hold water, has less minerals and nutrients, has less beneficial microorganisms, and ultimately – these things can lead to decreased yields and productivity, which in turn means less food production for the population.
- ongoing soil degradation reduces global harvests by a third of a percent each year under conventional farming practices
- the American economy losing roughly $37 billion in productivity annually from soil loss.
- About 60 percent of soil that is washed away [worldwide via soil erosion] ends up in rivers, streams and lakes, increasing the risks of flooding and intensifying water contamination from fertilizers and pesticides runoff.
You can read more about the effects and costs of land degradation and soil erosion at:
- https://www.farmprogress.com/soil-health/economics-soil-loss (the economics of topsoil loss on a farm)
How To Prevent Land Degradation, & Potential Solutions
It depends on the country and state/province as to the best strategy to prevent and solve short and long term land degradation.
Obviously, it depends heavily on the major causes of land degradation in that region as to what the prevention and solution strategies should be.
If we look at the general causes of land degradation, some solutions and prevention strategies related to those causes would be:
- Water & Wind Soil Erosion – farming practices like introducing ground cover, and building up the organic matter in the soil can help reduce the effects of water and wind erosion.
- Deforestation, Logging & Clearing Of Land – become more efficient with existing plots of farming land so less land has to be cleared in the future of agricultural land conversion. Introduce more tree planting and reforestation programs for farming land, logging land and cleared land affected by land degradation.
- Industrial Farming Methods > Organic & Sustainable Farming Practices – move more towards organic and sustainable agricultural practices that preserve land and soil health with minimal or even beneficial effects on yield and land production rates. Industrial farming methods like over application of fertilizer and pesticides, over grazing, over irrigation, too much tillage and so on – all extract more from land and soil without putting any nutrients back in the ground. Ground cover, no till farming, organic fertilizers and manure, drip irrigation, water and soil drains, and other techniques can all help preserve land.
- Farming Efficiency – become more efficient with existing farming practices. This means we can grow more food for a growing population on less land.
- Look At Our Diets – consider moving more towards plant based diets from animal products (meat and dairy). Plant based diets produce more food per person with less land than animal based products.
- Climate Change – look at the impact severe and changing weather events are having on soil health.
- Mining For Minerals, Metals & Fossil Fuels – more emphasis can be put on restoring mining sites. But also, we can look at re-using and recycling metals and minerals already mined and being used above ground. We can also look at moving towards renewable energy and electric cars – both of which mean we can eventually mine less fossil fuels from the ground.
- Landfills – ensure landfills are properly sealed so leachate doesn’t leak out and contaminate land/soil. Also, look at the benefits of moving further towards recycling over landfills.
- Factories & Industrial Waste – limit and minimise illegal or damaging dumping of industrial waste.
- Other Hazardous Waste – such as radioactive waste. Ensure treatment and disposal of this waste doesn’t damage land.
- Transport – run off from roads and highways usually comes from oil/petroleum. So, as mentioned above, moving towards alternate fuel vehicles may help.
- Water Pollution & Air Pollution – limit water pollution which can contaminate soil, and limit air pollution (where excess nitrogen in the air and acid rain can cause soil/land degradation issues)
- Restoring Damaged Land/Soil – soil that has been contaminated can be aerated and treated. Additionally, top soil that has been eroded can be renewed (slowly). Soil that is too acidic can be rebalanced. Land that has been desertified by weather, mining or other factors can be restored in various ways. This is all expensive and time consuming though. Bioremediation and phytoremediation are two examples of new/developing soil restoration technology.
- Recycling Damaged Land/Soil – instead of restoring the land, it might be recycled with an end use in mind. For example, former mining sites might become sites for solar panels and wind farms, or land fill sites might become parks.
- Regenerative Agriculture vs GMO Crops – some people think we can provide more food into the future with GMO technology, whilst others argue the downsides and disadvantages to it and prefer regenerative agriculture which focuses on organic and sustainable and holistic farming practices. We will have to choose in the future what balance of these two approaches to go with.
Some ideas from Greentumble.com:
- Economic incentives need to be put in place for farmers at the frontier of forests so that they intensify their production without expanding their land by cutting down the forests. (via ucsusa.org)
- Governments could put money into researching higher yielding varieties of tropical crops and then develop policies like subsidized seeds to encourage their use.
- The farmers could be educated by local extension agencies in sustainable practices like conservation tillage, cover crops, crop rotation and adding crop residuals to increase the fertility of their soil instead of fertilizers that cause greenhouse gas emissions, and land, water and air pollution.
- The inhabitants of the forests could be taught other methods of earning an income that do not jeopardize the forest habitat, like ecotourism in its purest sense or small-scale businesses harvesting sustainable amounts of the forest’s resources and replacing them.
- Insisting on organic food would be a very big start to reducing the adverse effects of agriculture on land. Requiring sustainable practices that help land regenerate and re-establish a community of beneficial organisms between crops would be helpful. Zoning requirements mandating havens of biological diversity at the edges of agricultural land, once the toxic chemicals are no longer in the equation of course, would work to promote the natural balance of life, where crickets and frogs and pollinators can all help make the land more productive.
- Populations eating less beef would go a long way to reducing the need for animal feed and land for grazing.
- Consuming less overall per person would go a long way to reducing land pollution
- Protect land via legislation. This applies too to regulations governing mining and industrial waste and disposal of solid and hazardous waste.
- The world’s population needs to be educated in the health hazards of soil pollutants to create an awareness of what is happening and the importance of being involved.
- A possibility is bringing religious leaders into the picture to help educate their followers. Very often there is a dichotomy on environmental issues as the theory of evolution invites an easy divisiveness between science and religion, but that gap should be bridged as we reach toward a common solution.
Some solutions to soil erosion and restoring saline soil:
- Restoration of eroded agricultural land is achieved through several agronomic and biological techniques. Crop rotations, agro-forestry, reduced tillage, cover crops, vegetative filter strips, residue, and no-till are important among these.
- Biological measures such as buffers, conditioner application in direct contact with the soil surface, crop residues using manure protect the soil from erosion.
- Restoration of saline agricultural land can be achieved through recharge stabilization and reconstruction of saline land through fencing, retain remnant vegetation, revegetation, runoff interception earthworks, and water table lowering.
- Financial support, public awareness, education and training, particularly of farmers, are necessary to accomplish such objectives. [as well as good policy, regulations and support by governments and land conservation organisation. Investment and further research and testing into sustainable farming and land restoration is also important]
- [subsidies, rewards and insurances for farmers who implement soil restoration practices may also be a priority]
- New farming practices like terraces and temporary “cover” crops have helped lower soil erosion by more than 40 percent over the past two decades
In particular with soil contamination – to resolve current issues with contamination, methods might include:
- Excavate soil and take it to a disposal site away from ready pathways for human or sensitive ecosystem contact.
- Aeration of soils at the contaminated site (with attendant risk of creating air pollution)
- Thermal remediation by introduction of heat to raise subsurface temperatures sufficiently high to volatize chemical contaminants out of the soil for vapor extraction. Technologies include ISTD, electrical resistance heating (ERH), and ET-DSP.
- Bioremediation, involving microbial digestion of certain organic chemicals. Techniques used in bioremediation include landfarming, biostimulation and bioaugmentating soil biota with commercially available microflora.
- Extraction of groundwater or soil vapor with an active electromechanical system, with subsequent stripping of the contaminants from the extract.
- Containment of the soil contaminants (such as by capping or paving over in place).
- Phytoremediation, or using plants (such as willow) to extract heavy metals.
- Mycoremediation, or using fungus to metabolize contaminants and accumulate heavy metals.
- Remediation of oil contaminated sediments with self-collapsing air microbubbles.
- Surfactant leaching
The FAO has this to say about land and soil reclamation and restoration:
- The effects of water and wind erosion are largely irreversible. Although plant nutrients and soil organic master may be replaced, to replace the actual loss of soil material would require taking the soil out of use for many thousands of years, an impractical course of action.
- In other cases, land degradation is reversible: soils with reduced organic master can be restored by additions of plant residues, degraded pastures may recover under improved range management. Salinized soils can be restored to productive use, although at a high cost, through salinity control and reclamation projects.
- Land reclamation frequently requires inputs which are costly, labour-demanding or both. The reclamation projects in salinized and waterlogged irrigated areas demonstrate this fact clearly. In other cases, the land can only be restored by taking it out of productive use for some years, as in reclamation forestry. The cost of reclamation, or restoration to productive use, of degraded soils is invariably less than the cost of preventing degradation before it occurs.
[So, some types of land degradation are reversible – but, there are time and cost considerations. And, you have to consider risk for farmers, as well as lost productivity opportunity.]
In terms of real life examples of rehabilitated land:
- … positive progress made by countries like Ethiopia, which has rehabilitated 7m hectares (17m acres).
- Lower levels of meat consumption, better land regulation and improved farming efficiency can help us prevent more land degradation in the future from agriculture
One of the best ways to prevent land degradation worldwide in the future would be to better map the world’s land and soil (with satellites and other technology), and track the impact of different factors (like deforestation, farming, weather etc.) on this land and soil. An example of how this is currently being done is the Global Land Outlook.
Recognizing The Challenges With Preventing Or Solving Land Degradation
If we take arable land and land with fertile topsoil for example – there are a number of approaches farmers are encouraged to take to prevent soil erosion.
However, these approaches can be time consuming, in some cases decrease yields, and eat at profits. They can also be a risk for farmers.
For farmers in poorer countries – these approaches may be completely unrealistic.
Another example is fossil fuels we mine from the ground. We want to use more renewable green energy that makes use of solar and wind power – but that technology has it’s challenges too and can’t yet supply all our energy needs.
These are multi layered realities we have to face if we truly want to address land degradation.