Causes of land degradation
Land degradation is a process in which the value of the physical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable. Land degradation definitions usually exclude natural causes - examples of which include floods and fires although increasingly, human activity indirectly impacts on these too.
Land degradation measures
Land degradation is a broad term that can be applied differently across a wide range of scenarios. There are various 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.
Action in the land's 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 defining land degradation is that what one group of people might view as degradation, others might view as a benefit or opportunity underlining the tensions over land use.
Land degradation types
There are numerous types of land degradation that have been described.
The more established types have been joined by a raft of new variants in more recent times.
Traditional types include:
- wind-induced land degradation
- mechanically-induced land degradation (mechanised agricultural practices)
- chemically-induced land degradation (e.g. nitrogen runoff)
- biologically-induced degradation (e.g. cattle grazing)
Emerging in more recent times:
- pollution, often chemical, due to agricultural, industrial, mining or commercial activities
- loss of arable land due to urban construction
- artificial radioactivity, sometimes accidental
- land-use constraints associated with armed conflicts
Land degradation causes
Land degradation is a global problem largely related to agricultural use.
- Land clearance, such as clearcutting and deforestation
- Agricultural depletion of soil nutrients through poor farming practices
- Livestock including overgrazing
- Inappropriate irrigation
- 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
- Soil degradation, e.g. soil contamination, soil erosion, soil acidification, loss of soil carbon
- Climate change (man-made) leading to sea level rises making once-fertile areas too saline (salty) for agricultural purposes
- Improper use of fertilisers, particulalry nitrogen and phosphorous