Land degradation is a process in which the value of the biophysical environment is affected by one or more combination of human-induced processes acting upon the land. also environmental degradation is the gradual destruction or reduction of the quality and quantity of human activities animals activities or natural means example water causes soil erosion, wind, etc. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable. Natural hazards are excluded as a cause, however human activities can indirectly affect phenomena such as floods and bush fires.
This is considered to be an important topic of the 21st century due to the implications land degradation has upon agronomic productivity, the environment, and its effects on food security. It is estimated that up to 40% of the world's agricultural land is seriously degraded.
Land degradation is a broad term that can be applied differently across a wide range of scenarios. There are four main ways of looking at land degradation and its impact on the environment around it:
- A temporary or permanent decline in the productive capacity of the land. This can be seen through a loss of biomass, a loss of actual productivity or in potential productivity, or a loss or change in vegetative cover and soil nutrients.
- A decline in the lands “usefulness”: A loss or reduction in the lands capacity to provide resources for human livelihoods. This can be measured from a base line of past land use.
- Loss of biodiversity: A loss of range of species or ecosystem complexity as a decline in the environmental quality.
- Shifting ecological risk: increased vulnerability of the environment or people to destruction or crisis. This is measured through a base line in the form of pre-existing risk of crisis or destruction.
A problem with measuring land degradation is that what one group of people call degradation, others might view as a benefit or opportunity. For example, heavy rainfall could make a scientific group be worried about high erosion of the soil while farmers could view it as a good opportunity to plant crops.
- Land clearance, such as clearcutting and deforestation
- Agricultural depletion of soil nutrients through poor farming practices
- Livestock including overgrazing and overdrafting
- Inappropriate irrigation and overdrafting
- Urban sprawl and commercial development
- Soil contamination
- Vehicle off-roading
- Quarrying of stone, sand, ore and minerals
- Increase in field size due to economies of scale, reducing shelter for wildlife, as hedgerows and copses disappear
- Exposure of naked soil after harvesting by heavy equipment
- Monoculture, destabilizing the local ecosystem
- Dumping of non-biodegradable trash, such as plastics
The main outcome of land degradation is a substantial reduction in the productivity of the land. The major stresses on vulnerable land include:
- Accelerated soil erosion by wind and water
- Soil acidification and the formation of acid sulfate soil resulting in barren soil
- Soil alkalinisation owing to irrigation with water containing sodium bicarbonate leading to poor soil structure and reduced crop yields
- Soil salination in irrigated land requiring soil salinity control to reclaim the land 
- Soil waterlogging in irrigated land which calls for some form of subsurface land drainage to remediate the negative effects 
- Destruction of soil structure including loss of organic matter
Overcutting of vegetation occurs when people cut forests, woodlands and shrublands—to obtain timber, fuelwood and other products—at a pace exceeding the rate of natural regrowth. This is frequent in semi-arid environments, where fuelwood shortages are often severe.
Overgrazing is the grazing of natural pastures at stocking intensities above the livestock carrying capacity; the resulting decrease in the vegetation cover is a leading cause of wind and water erosion. It is a significant factor in Afghanistan.
Agricultural activities that can cause land degradation include shifting cultivation without adequate fallow periods, absence of soil conservation measures, fertilizer use, and a host of possible problems arising from faulty planning or management of irrigation. They are a major factor in Sri Lanka and the dominant one in Bangladesh.
The role of population factors in land degradation processes obviously occurs in the context of the underlying causes. In the region, in fact, it is indeed one of the two along with land shortage, and land shortage itself ultimately is a consequence of continued population growth in the face of the finiteness of land resources. In the context of land shortage the growing population pressure, during 1980-1990, has led to decreases in the already small areas of agricultural land per person in six out of eight countries (14% for India and 22% for Pakistan).
Population pressure also operates through other mechanisms. Improper agricultural practices, for instance, occur only under constraints such as the saturation of good lands under population pressure which leads settlers to cultivate too shallow or too steep soils, plough fallow land before it has recovered its fertility, or attempt to obtain multiple crops by irrigating unsuitable soils.
High population density is not always related to land degradation. Rather, it is the practices of the human population that can cause a landscape to become degraded. Populations can be a benefit to the land and make it more productive than it is in its natural state. Land degradation is important factor of internal displacement in many African and Asian countries
Severe land degradation affects a significant portion of the Earth's arable lands, decreasing the wealth and economic development of nations. As the land resource base becomes less productive, food security is compromised and competition for dwindling resources increases, the seeds of famine and potential conflict are sewn.
Sensitivity and resilience 
Sensitivity and resilience are measures of the vulnerability of a landscape to degradation. These two factors combine to explain the degree of vulnerability. Sensitivity is the degree to which a land system undergoes change due to natural forces, human intervention or a combination of both. Resilience is the ability of a landscape to absorb change, without significantly altering the relationship between the relative importance and numbers of individuals and species that compose the community. It also refers to the ability of the region to return to its original state after being changed in some way. The resilience of a landscape can be increased or decreased through human interaction based upon different methods of land-use management. Land that is degraded becomes less resilient than undegraded land, which can lead to even further degration through shocks to the landscape.
Climate change 
Significant land degradation from seawater inundation, particularly in river deltas and on low-lying islands, is a potential hazard that was identified in a 2007 IPCC report. As a result of sea-level rise from climate change, salinity levels can reach levels where agriculture becomes impossible in very low lying areas.
See also 
- Conacher, Arthur; Conacher, Jeanette (1995). Rural Land Degradation in Australia. South Melbourne, Victoria: Oxford University Press Australia. p. 2. ISBN 0-19-553436-0.
- Johnson, D.L., S.H. Ambrose, T.J. Bassett, M.L. Bowen, D.E. Crummey, J.S. Isaacson, D.N. Johnson, P. Lamb, M. Saul, and A.E. Winter-Nelson. 1997. Meanings of environmental terms. Journal of Environmental Quality 26: 581-589.
- Eswaran, H.; R. Lal and P.F. Reich. (2001). "Land degradation: an overview". New Delhi, India: Oxford Press. Retrieved 2012-02-05. Unknown parameter
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- Ian Sample (2007-08-31). "Global food crisis looms as climate change and population growth strip fertile land". The Guardian. Retrieved 2008-07-23.
- Stockings, Mike; Murnaghan, Niamh. (2000), Land Degradation - Guidelines for Field Assesment, Norwich, UK, pp. 7–15
- ILRI (1989), Effectiveness and Social/Environmental Impacts of Irrigation Projects: a Review, In: Annual Report 1988 of the International Institute for Land Reclamation and Improvement (ILRI), Wageningen, The Netherlands, pp. 18–34
- "Land: Programmes and Activities". United Nations Environment Programme. Retrieved 2008-07-19.
- "Free articles and software on drainage or waterloged land and soil salinity control". Retrieved 2010-07-28.
- Terminski, Bogumil, Towards Recognition and Protection of Forced Environmental Migrants in the Public International Law: Refugee or IDPs Umbrella (December 1, 2011). Policy Studies Organization (PSO) Summit, December 2011
- Johnson, Douglas; Lewis, Lawrence. (2007), Land Degradation; Creation and Destruction, Maryland, USA
Further reading 
- "Human Induced Land Degradation is Preventable". United States Department of Agriculture - Natural Resources Conservation Service. Retrieved 2006-06-20. This article incorporates text in the public domain produced by the USDA Natural Resources Conservation Service
- Eswaran, H.; R. Lal and P.F. Reich. (2001). "Land degradation: an overview". Responses to Land Degradation. Proc. 2nd. International Conference on Land Degradation and Desertification. New Delhi, India: Oxford Press. Retrieved 2006-06-20.
- D.L. Johnson and L.A. Lewis Land Degradation:Creation and Destruction, 2nd edition, Rowman and Littlefield, Lanham, Boulder, New York, Toronto, Oxford, 2007.