Land degradation

Topic: Geographical Issues: Pollution, Urban Waste, Slums and Land Degradation · NCERT: Class 10, Ch 1 "Resources and Development"; Class 12, Ch 3 "Land Resources and Agriculture"; Class 12, Ch 9 "Geographical Perspective on Selected Issues and Problems"

Meaning

Land degradation is a temporary or permanent fall in the land's power to produce. It happens through soil erosion, waterlogging, salinisation, alkalinisation, or growing crops again and again without putting nutrients back. It matters because nearly 30% of India is degraded [3][4]. Degraded land lowers farm output and incomes. If nobody checks it, the land can turn into wasteland (degraded land left unused or under-used).

Explanation

1. Five causes (NCERT)

• Soil erosion: water or wind carries away the fertile top layer of soil.
• Waterlogging: water stays in the soil for a long time, so roots cannot breathe.
• Salinisation: salts build up in the soil.
• Alkalinisation: sodium salts build up and the soil turns alkaline. In north India these soils are called usar, reh or kallar.
• Continuous use without managing fertility: the same land is cropped again and again. Nutrients are not put back through manure, fallowing (resting the land) or crop rotation.
• Degradation can come from natural processes, from human action, or from both together.

2. How canal irrigation ruins land (cause → process → result)

• Cause: too much canal water
• Farmers use more water than crops need.

• Water seeps down from canals and fields, so the water table (the top level of underground water) rises.

• Process: rise and evaporation

• In a hot climate, this water moves up through the soil to the surface.

• At the surface the water evaporates, but the salts in it stay behind.

• Result: two problems at once

• A white salt crust forms, so the soil becomes saline/alkaline.
• The field also becomes waterlogged.

3. How gullies and ravines form (badlands)

• Gully: a deep, narrow channel that running water cuts into soft soil. Ravine: a bigger and deeper gully. Badland topography: a large area cut up by many ravines.
• Steps:
• Soft alluvium (silt and clay laid down by rivers) lies on the river banks.
• Heavy monsoon rain runs over bare slopes and cuts small channels called rills.

• The rills grow deeper and wider. They become gullies, and then ravines.

• What speeds it up: deforestation (cutting trees) and overgrazing strip away the plant cover that holds the soil in place.

• Result: farmland is lost, villages are cut off, and the land gives hiding places to outlaws (the dacoits of the Chambal).

4. Degraded land vs wasteland, and the NRSC classes

• Not all degraded land is wasteland. A field that has lost some fertility can still be farmed. If degradation goes unchecked, the land slowly becomes wasteland.
• NRSC (National Remote Sensing Centre, ISRO, Hyderabad) maps wastelands with remote sensing (studying satellite images instead of surveying on foot). It sorts them into three groups:

Group	Wasteland types
(i) Natural agents	Gullied and ravinous land; desert and coastal sands; barren rocky areas; steep slopes; glacial areas
(ii) Natural + human factors	Waterlogged and marshy land; saline and alkaline land; land with or without scrub
(iii) Human action	Degraded shifting cultivation areas; degraded plantation land; degraded forests; degraded pastures; mining and industrial wastelands

• NCERT says man-made wastelands matter more than natural ones.
• Natural wastelands, such as glaciers or bare rock, are hard to change.
• Man-made wastelands come from overgrazing, mining, bad irrigation and shorter jhum cycles (less time before a forest plot is cleared again).

• Because people caused them, better land management can prevent and reverse them.

• Mining and industrial wastelands: overburden dumps (waste rock and soil removed to reach the ore), open pits and fly-ash ponds leave the land bare and polluted.

Where it occurs

• Gullied and ravinous land (natural agents):
• Chambal: rises in the Vindhya Range near Mhow (MP). It flows north-east through Kota (Rajasthan), forms part of the MP–Rajasthan border, and joins the Yamuna in Etawah district (UP). The worst ravines are in Morena and Bhind (MP), Dholpur (Rajasthan) and Agra–Etawah (UP).
• Yamuna: ravines along its banks in the Agra–Etawah stretch.

• Mahi: rises in the Vindhyas in MP, flows through southern Rajasthan and Gujarat, and enters the Gulf of Khambhat (Arabian Sea). It crosses the Tropic of Cancer twice.

• Desert sands: Thar Desert, western Rajasthan. Glacial areas and steep slopes: the Himalaya.

• Waterlogging and salinity/alkalinity: canal command areas (farmland served by a canal) of Punjab, Haryana and western UP, and the Indira Gandhi Canal command area in Rajasthan. Coastal marshes are also in this group.
• Shifting cultivation (jhum): the north-east hills.
• Mining wastelands: mining belts of Jharkhand, Odisha and Chhattisgarh.
• How big the problem is (the two atlases):
• Wastelands Atlas of India – 2019 (DoLR + NRSC, fifth edition, made from IRS satellite data): 55.76 Mha, or 16.96% of India, in 2015-16. Wasteland was about 56.6 Mha in 2008-09, so 0.84 Mha (0.26%) was turned back to productive use [2].

• Desertification and Land Degradation Atlas of India (SAC–ISRO, Ahmedabad, released 2021): 97.84 Mha in 2018-19, nearly 30% of India [3][4]. It tracks change over 15 years, from 2003-05 to 2018-19 [3]. Water erosion is the main process. Rajasthan, Maharashtra and Gujarat have the largest degraded areas.

• World: the UNCCD (UN Convention to Combat Desertification) is the UN treaty on desertification, land degradation and drought. Its goal of Land Degradation Neutrality is SDG 15.3.

Don't confuse with

• Wasteland: wasteland is degraded land that is unused or under-used. Degraded land is the bigger set and includes land that is still farmed. This is why wasteland can fall (55.76 Mha) while total degradation rises (97.84 Mha) [2][3].
• Desertification: this is land degradation only in dry areas (arid, semi-arid and dry sub-humid zones). Land degradation can happen in any climate, including waterlogging in wet canal areas.
• Natural vs human-caused wasteland (NRSC): gullies and ravines are classed as natural agents. Waterlogged and saline/alkaline land is natural + human, not human alone. Degraded pastures, jhum areas and mining land are human-made.
• Salinisation vs alkalinisation: salinisation is a build-up of salts in general. Alkalinisation is a build-up of sodium salts that makes the soil alkaline (usar/reh/kallar). It is reclaimed with gypsum, which replaces the sodium.

Prelims Hooks

• NRSC (Hyderabad) puts gullied and ravinous land under natural agents. Classic valleys: Chambal, Yamuna, Mahi.
• Trap: waterlogged and saline/alkaline land comes from natural + human factors, not from human action alone.
• Wastelands Atlas 2019: DoLR + NRSC, 5th edition, 55.76 Mha (16.96%) in 2015-16 [2].
• Desertification and Land Degradation Atlas: SAC–ISRO, Ahmedabad. 97.84 Mha in 2018-19 (about 30%). Main process: water erosion. Top states: Rajasthan > Maharashtra > Gujarat [3][4].
• LDN = SDG 15.3, under the UNCCD. Under LDN, every area of degraded land is balanced by restoring an equal area.
• Bonn Challenge (2011, IUCN + Germany): 150 Mha by 2020 and 350 Mha by 2030. India's target is 26 Mha by 2030, announced at UNCCD COP14, New Delhi, 2019. This is the largest pledge so far [S3a][5]. 21.76 Mha is under restoration (June 2026) [5].

Mains Points

• Causes: man-made degradation is the bigger issue (GS-I/GS-III)
• Canals cause waterlogging and salinity in Punjab–Haryana and the Indira Gandhi Canal area.
• Overgrazing damages dry Rajasthan and Gujarat. Shorter jhum cycles damage the north-east.
• Mining dumps scar Jharkhand and Odisha.

• NCERT stresses these because they can be prevented and reversed.

• What the data shows (GS-III)

• Wasteland fell by 0.84 Mha between 2008-09 and 2015-16 [2].
• But degraded land is about 30% of India and has been rising since 2003-05 [3].

• So the hidden problem is degradation, mainly water erosion, inside farmed land. Policy must look beyond "wastelands".

• Effects and response (GS-III)

• Effects: lower farm incomes, migration, more runoff and silt in rivers, and greater desertification and drought risk.
• Response: LDN (SDG 15.3) and the 26 Mha Bonn target need several measures:
  • watershed management (treating the whole drainage area from ridge to valley)
  • afforestation, gully plugging and check dams
  • contour bunding and terracing (earth ridges and steps on slopes)
  • controlled grazing
  • gypsum and drainage for saline soils
  • shelterbelts (rows of trees that break the wind) on desert sands
• India uses a landscape restoration approach, which treats farms, forests and water together [S3a][5].

Related concepts

• Wasteland
• Gullied and ravinous land
• Man-made wastelands
• Wastelands Atlas of India
• Desertification and Land Degradation Atlas of India
• Land Degradation Neutrality
• Bonn Challenge

Read more

• Land degradation and wastelands