Soil is a decisive asset for mankind. It provides a tremendous amount of goods and ecosystem services that sustain life through regulating, supporting and supplying roles. Soil delivers its services by chemical, physical and biological processes. Nutrient cycling, water regulation, and other soil functions are normal processes occurring in all ecosystems. Soil benefits come in many forms to humans, such as food production, rain and snow infiltration and water quality, which can improve quality of life. People can increase or decrease these values of soil trough proper or inappropriate land-management choices that affect soil functions. The optimal goal of this review is to bring awareness to the issue of wind erosion around the globe and place a dollar value to degradation of this asset.
According to experts in the field, it is estimated that roughly 28% of global land area experiences land degradation. The cause of such degradation is due to wind-driven erosion processes. A total land area of 549 million hectares (ha) is potentially affected by wind erosion, of which 296 million ha could be severely affected (1).
Vegetation and Soil is all gone
In many parts of the world, organizations are now testing the limits of the resilience and multi-functional capacities of soil. Nearly two billion ha of land are globally affected by human-induced degradation of soil. The food needs of increasing population is leading to even greater intensification of agricultural practices, stretching thereby the capacity of soil to release and absorb nutrients and chemicals (2).
Degradation of Land in Iran, Fars Province, Middle Zagros
Wind erosion is a major threat to ecosystems and food sustainability. The wind erosive force is in action on every continent of the planet. Some soils may be eroding faster than they are being formed. With increasing pressure on agricultural land to produce more food for a growing population, pressure will be on to grow crops on drier marginal lands, which are more vulnerable to wind erosion. One of the countries experiencing this problem is Australia. At the same time, the areas that are affected by moderate or severe wind erosion (currently 17%, nearly 130 million ha) are likely to expand due to increased drought and climate variability associated with climate change (3).
Massive Sand Dunes in Central Kavir, Iran
It is therefore crucial to understand the benefits and values we derive from soil, so we can appreciate the importance of managing land in a way that maintains soil functions for a sustainable future. The United Nations Food and Agriculture Organisation (FAO) estimated that 24 billion tons of soil were lost in 2011, which amounts to some 3.4 tons of lost soil per person. FAO estimates that one quarter of the world’s 13 billion hectares of land is degraded. In the pursuit of greater yields and profits we have compromised soil health, mining soils for nutrients, over-using fertilizers, creating over 4 billion hectares of man-made deserts and depleting over 8 billion hectares of deep organic soils (4). One of the greatest threats to soil is accelerated erosion, which raises a natural process to unsustainable levels, and has downstream consequences (e.g. economic, environmental and social). Global intensification of agro-ecosystems is a recognized major cause of soil erosion that, in light of predicted population growth and increased demand for food security, will continue or increase (5).
Dust and sand in the air, Saqand area, Yazd Province
One of the important issues that soil erosion valuation data is missing is the status of soil biota (6). Transport and redistribution of biota by soil erosion has formerly been ignored and thus is poorly understood. With the move to sustainable intensification this is a key knowledge gap that needs to be addressed. Here as investigators attempt to highlight the erosion mechanisms in soil types to differentiate various forms of erosion, it seems very appropriate to argue that soil nematodes are a good model taxa to investigate the erosion’s impacts on soil biota all across soils (7). Some investigators have primarily highlighted the different known mechanisms of soil erosion that have impacts on soil biota in general, and nematodes in particular in tropical regions. Based on the availability of limited literature, using nematodes as a model organism, man should outline future research priorities to initially address the important interrelationships between soil erosion processes and soil biota (8).
Desertification around Qom, Iran
Soil erosion has both on-site and off-site effects. Loss of soil productivity is the main on-site effect, while enhanced productivity of downstream land, sedimentation and eutrophication of waterways and reservoirs are common off-site effects. Estimations of soil erosion costs are therefore difficult and complex because the on-site effects are often compensated by the use of increased amounts of fertilizers that mask the productivity losses, and because the cost of environmental goods and services depends greatly on the views of different stakeholders with different viewpoints. Therefore, estimates of soil erosion costs are widely variable and controversial (9).
Sheet Erosion in South Kerman Province, Flood and Wind Erosion
At the extreme high side, Pimentel et al, stated that the total on- and off-site costs of damages by wind and water erosion and the cost of erosion prevention each year is $44,399,000,000 in the USA alone (10). On the other extreme, Pierre Crosson estimated the loss in farm income in the USA per year at just $100 million USD (11). On the other hand, conservation programs best serve the public when their funding, design, and implementation maximize benefits relative to costs. Unlike the cost of soil conservation efforts, environmental benefits of decreasing soil erosion are not easy to measure. Information on the values of soil conservation benefits can however, aid in designing more cost-effective programs and evaluating accomplishments of programs, policies, and practices (12).
Infinite of Sand Dunes Around Bafq City, Yazd Province
USDA-NRCS reports that the productivity of some lands has declined by 50% due to soil erosion and desertification. Yield reduction in Africa due to past soil erosion may range from 2 to 40%, with a mean loss of 8.2% for the continent. In South Asia, annual loss in productivity is estimated at 36 million tons of cereal equivalent valued at $5,400 million (number needs revising) by water erosion, and $1,800 million USD (this would be a billion) due to wind erosion. It is estimated that the total annual cost of erosion from agriculture in the USA is about $44 billion USD per year, i.e. about US$247 per ha of cropland and pasture. On a global scale the annual loss of 75 billion tons of soil costs the world about US$400 billion per year, or approximately US$70 per person per year (13).
Sand Dune Invasion into Plantation
There are also serious (20%) productivity losses caused by erosion in Asia, especially in India, China, Iran, Israel, Jordan, Lebanon, Nepal, and Pakistan (13).
Big Sand in Central Kavir, Iran
Land degradation and desertification threaten fertile land and the benefits which human society derives from it throughout the world. On a global scale, around 10 – 20% of drylands and 24% of the world’s productive lands are degraded. The consequences are alarming: food insecurity, poverty, reduced availability of clean water, and increased vulnerability of affected areas to climate change. It is estimated that 1.5 billion people across the world are already directly affected through reduced income or food security. The annual economic losses due to deforestation and land degradation were estimated at 1.5 – 3.4 trillion Euro in 2008, equaling 3.3 – 7.5% of global GDP in 2008 (14).
It is widely recognized that accelerated soil erosion related to agricultural activities is a serious global problem. While the economic consequences of water-based soil erosion have received considerable attention, those from wind erosion have received little. Wind erosion occurs widely in arid and semiarid regions, which account for about one-third of the world’s area and contain about one-sixth of the world’s population (15).
Land Degradation in Qashqai Land in Fars Province
The total area in the world prone to wind erosion is estimated to be around 20 percent of global land area. In eight of ten Great Plains states in the United States, wind erosion exceeds water erosion (16). Similar to water erosion, wind erosion is worsened by human perturbations. However, unlike with water erosion, there are few measurements of the magnitude of wind erosion in different geographic locations. Estimating soil loss by wind erosion is more complex than estimating upland erosion by water (17).
Flood and Wind Erosion in Yazd Province
Meibodi et al calculated the costs related to dust storms in countries of Iran and Iraq as $1043.5 and 1404.0 million annually for year 2013 (18). According to a senior environmental official, the cost of soil erosion in Iran trumps the country’s oil revenue. “Between two and four billion tons of soil wears away in Iran every year. If the numbers are correct, the rate of soil erosion in Iran is 20 times over and above the global average. “With an estimated price of $28 per ton, soil erosion costs Iran between $56 billion and $112 billion.” Iran earned $53.6 billion in oil exports in 2014 (19).
Flood and Wind Erosion between Kerman and Balouchestan Provinces, Iran
Several studies have estimated the on-site and off-site benefits and costs associated with conservation practices aimed at reducing water-based soil erosion (20). Far fewer studies exist of the costs and benefits of reducing wind erosion. Davis and Condra have estimated the on-site costs of wind erosion in New Mexico, including damage to crops by wind-eroded soil and reduced soil productivity. They estimated total on-site damages from wind erosion of $10 million per year (21). Huszar and Piper surveyed households, businesses and government agencies and found that the off-site costs of wind erosion in New Mexico are much larger than the estimated on-site costs totaling $466 million per year (22).
In Tajikistan the on-site costs of land degradation associated with lost crop productivity and declines in milk production is estimated at US$ 442 million per year – 7.8% of GDP — at the national level. While this initial estimate of the cost of land degradation to the economy may be considered an overestimate given that it is a gross, rather than a net value (that is the costs of production have not been deducted), there are a number of reasons why it may in fact be an underestimate (23).
Overgrazing and Land Degradation in Qashqai Area, Fars Province
Socio-economic policies in the UK reflected in land use are a major influence on how the land is farmed and therefore on erosion and pollution. According to some research the external costs of farming can be directly related to erosion in 1996 was £304 million. These may be compared with (or added to) the £3 billion that taxpayers are spending annually on agricultural support in the UK (24).
Overall Estimated Cost of Environmental Degradation in Algeria in 1999 according to a world bank report Damage cost to Algeria is 3.6% of GDP. Damage cost estimates should be considered orders of magnitude. Mean estimate: Algerian Dinars 97 billion annually (US$1.7billions) Damage cost to the global environment: About 1.2% of GDP (25).
If the degree and extent of wind erosion is compared with that of water erosion, the total impact of the two is comparable. Areas affected by moderate and strong wind erosion are similar to those of water erosion, around 35 and 12 M ha respectively. The area for light wind erosion is only 40% of that for water erosion, but on the assumptions used above, this has a relatively small effect on production. Being confined to dry climates, the average productivity of land affected by wind erosion will be less than that affected by water erosion. Suppose that on average, it is one third as productive. The production loss from water erosion was assessed at US$5 400 M per year. For an impact of similar severity, the production loss from wind erosion is of the order of US$1800 M per year. This impact is very unevenly distributed in the region, being entirely for the countries of the dry zone: Afghanistan, Iran, Pakistan and the dry region of India (26).
Endemic Sand Dune Natural Vegetation
Costs are calculated on the basis of on-site effects (losses within the productive unit) and off-site effects (damage caused beyond the agricultural property). In the United States, the annual cost of soil erosion for both on-site and off-site effects has been estimated at 44 billion dollars a year (27). Currently, about 80% of the world’s agricultural land suffers moderate to severe erosion, while 10% experiences slight erosion. Worldwide, erosion on cropland averages about 30 t/ha/year and ranges from 0.5 to 400 t/ha/year. As a result of soil erosion, during the last 40 years about 30% of the world’s cropland has become unproductive and much of that has been abandoned for growing crops (28).
Soil erosion has been a public concern in the US since 1930. However, quantification of the problem has been elusive, and average annual U.S. cropland soil erosion losses have been given as 2 billion, 4.0 billion, 4.5 billion, 4.8 billion, 5 billion or 6.8 billion tons. The U.S. Department of Agriculture (USDA) National Resource Inventory (NRI), based on models, gave high values in the 1970s and 1980s but has shown decreases in the past decade. Some sources have suggested that recent erosion is as great as or greater than that of the 1930s, when the soil conservation effort was begun. Increases in spending for soil conservation have been many billion dollars (29).
A Student Excursion to visit a Soil Conservation and Watershed Management Project
While the above studies demonstrate that damages from wind erosion can be large, they do not assess the economic feasibility of specific soil conservation practices. Such an assessment requires estimations by which conservation practices would decrease soil erosion, and the costs of implementing those practices. Reviewing these research findings reveals many harsh facts about the problem. However, most of them lack a reliable methodology. Certainly, accurate estimation of wind erosion damages is difficult due to the nature of its dynamics and complexity. It also appears that various interested sides confronting this issue, including both the public sphere and landowners, have their own agenda in mind. At the same time, the environmental benefits of wind erosion control are not easy to precisely quantify due to its unknown magnitude.
Wind erosion is a worldwide phenomenon. Little information about its economic impacts is available, even for Western countries. The large amount of soil moved by wind erosion globally testifies to the need for more research with region-specific standards on both the on-site and off-site impacts. Research findings remind us that wind erosion’s off-site effects can be decisive in changing the ranking of alternative policies. This fact points out the need for incorporating wind’s erosion off-site damages in policy analyses. However, in many cases a conservative estimate may result in a decisive policy decision.
It is difficult to obtain even the most approximate estimate of the economic cost of wind erosion because the affected land is partly under farming use or livestock production, and there is virtually no basis for estimating the effects of erosion upon production. A conservative estimate could be obtained by benefit transfer, using an original non-market valuation study conducted in a developed country. At the moment, however, there are too few such studies available, and those that do exist have tended to focus on air quality in cities that suffer from industrial pollution, rather than areas that suffer from soil-derived dust pollution. Also, there is a serious need for further research focusing on benefit transfer approaches. With additional data, estimate of off-site benefits could be explored in greater depth.
Soil loss and deterioration will continue and will probably accelerate if proper and prompt measures are not taken. Solving soil erosion problems will help solve other problems at the national and global levels as well. Soil conservation will have multiple benefits. As the diversity and multi-functionality of soil contribute to natural diversity, resource availability, and people’s ability to cope with daily changes. Combating soil degradation will help offset greenhouse gas emissions, improve the environment, guarantee more food for increasing populations and will contribute to the economic progress of future generations.
As soil is a unique and irreplaceable asset, its assessment approaches and conservation policies need to incorporate a wide range of perspectives. This means it would be necessary to integrate assessments and policies at every social and international level. Since soil erosion is a global issue, all soil related plans, especially in the Middle Eastern countries, need to be carefully analyzed and strictly monitored by a joint local and internationally recognized experts body. Ideally such results should be communicated on a regular basis through, for example, a soil reporting mechanism and assessment framework.
Sustainable development of communities with such fragile ecosystems requires implementation of the essential recommendations of combating desertification to mitigate the effects of drought. Effective institutional coordination among the relevant stakeholders is an immediate need. Also, promotion of teamwork amongst disparate actors toward implementation of expert opinion, legislations and conservation plans can serve the mankind to a great extent. In the decades to come, the sustainable use of soil will be a huge challenge, comparable to and closely interrelated with the global concerns on climate change, global warming and biodiversity. These challenges would require the immediate actions to be taken in order to meet the diverse and potentially conflicting demands on the soil resource without compromising its use and availability to future generations.
1. Soil threats in Europe: status, methods, drivers and effects on ecosystem services (2015). A review report, deliverable 2.1 of the RECARE project.
2. Priti Gupta (2013). SOIL AND ITS ECONOMIC IMPLICATIONS IN INDIA, International Journal of Research and Development in Pharmacy and Life Sciences, 2:6, 650-666.
5. Dennis McLaughlin and Wolfgang Kitzelbach (2015). Food security and sustainable resource management. Water Resources Research, 51:4966-4985.
6. TEEB (2010). The Economics of Ecosystems and Biodiversit: Ecological and Economic Foundations. London and Washington, Earthscan.
8. N. Labrière et al (2015). Soil erosion in the humid tropics: A systematic quantitative review, Agriculture, Ecosystems and Environment, 203: 127–139.
10. David Pimentel et al (1995). Environmental and Economic Costs of Soil Erosion and Conservation Benefits. Science, New Series, 267(5201)1117-1123.
11. Pierre Crosson (2007). Soil Quality and Agricultural Development. Chapter 57 in Handbook of Agricultural Economics, Vol. 3:2911-2932.
12. LeRoy Hansen and Marc Ribaudo (2008). USDA Economic Measures of Soil Conservation Benefits: Regional Values for Policy Assessment, Technical Bulletin, 1922.
15. DREGNE, H.E., ed. 1992. Degradation and Restoration of Arid Lands. Lubbock: Texas Technical University.
16. Lal, R. 2001. Soil degradation by erosion. Land Degradation & Development, 12 : 519 – 539.
17. Lal, R. 1998. Soil erosion impact on agronomic productivity and environment quality: Critical Review. Plant Science, 17 : 319 – 464.
18. Ali Emami Meibodi et al (2015). Economic Modeling of the Regional Polices to Combat Dust Phenomenon by Using Game Theory. Procedia Economics and Finance, 24:409 – 418.
20. Sfeir-Younis, A. and Dragun, A.K. (1993). Land and Soil Management. Boulder, Colorado and Oxford, England: Westview Press.
21. Davis, Bob and Gary Condra (1989). ‘The On-Site Costs of Wind Erosion on Farms in New Mexico. Journal of Soil and Water Conservation, 44(4) 339-343.
22. Huszar, P.C. & Piper, S.L. (1986). Estimating the Off-site Costs of Wind Erosion in New Mexico. Journal of Soil and Water Conservation, Nov-Dec: 414-416.
24. John Boardman, Jean Poesen, Robert Evans (2006). Socio-economic factors in soil erosion and conservation. Environmental Science & Policy, 6:1–6.
27. David Pimentel and Michael Burgess (2013). Soil Erosion Threatens Food Production. Agriculture, 3:443-463.
28. Stanley W. Trimble and Pierre Crosson (2000). US Soil Erosion Rates: Myth and Reality. Science, 289(5477)248-250.