17. What is Land Degradation? What are the different causes of land degradation in India
explain with
examples.
Answers
Answer:
Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land.[1] It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable.[2] Natural hazards are excluded as a cause; however human activities can indirectly affect phenomena such as floods and bush fires.
Serious land degradation in Nauru after the depletion of the phosphate cover through mining
This is considered to be an important topic of the 21st century due to the implications land degradation has upon agricultural productivity, the environment, and its effects on food security.[3] It is estimated that up to 4% of the world's agricultural land is seriously degraded.[4]
According to the Special Report on Climate Change and Land of the Intergovernmental Panel on Climate Change: "About a quarter of the Earth's ice-free land area is subject to human-induced degradation (medium confidence). Soil erosion from agricultural fields is estimated to be currently 10 to 20 times (no tillage) to more than 100 times (conventional tillage) higher than the soil formation rate (medium confidence).".[5]
The United Nations Sustainable Development Goal 15 has a target to restore degraded land and soil and achieve a land degradation-neutral world by 2030.[6]
Measures Edit
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.
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. For example, planting crops at a location with heavy rainfall and steep slopes would create scientific and environmental concern regarding the risk of soil erosion by water, yet farmers could view the location as a favourable one for high crop yields.[7]
Different types Edit
Potato field with soil erosion
In addition to the usual types of land degradation that have been known for centuries (water, wind and mechanical erosion, physical, chemical and biological degradation), four other types have emerged in the last 50 years:[8]
pollution, often chemical, due to agricultural, industrial, mining or commercial activities;
loss of arable land due to urban construction, road building, land conversion, agricultural expansion, etc.;
artificial radioactivity, sometimes accidental;
land-use constraints associated with armed conflicts.
Overall, more than 36 types of land degradation can be assessed. All are induced or aggravated by human activities, e.g. soil erosion, soil contamination, soil acidification, sheet erosion, silting, aridification, salinization, urbanization, etc.