Soil Erosion in India: Types, Causes, Degradation and Conservation

Overview

Soil erosion is the removal of the soil cover and its washing down by water, wind and other agents. Soil erosion in India matters because soil forms very slowly. Soil formation and erosion normally go on together and balance each other. Deforestation, over-grazing, construction and mining upset that balance, and estimates put India's loss of soil at about 5.3 billion tonnes a year. Erosion is the most visible part of a wider problem, land degradation, the loss of the land's productive capacity, which also includes salinisation, waterlogging, acidity and chemical damage. Conservation answers each process with its own remedy, backed by national schemes and India's pledge to restore 26 million hectares of degraded land by 2030.

Types of Soil Erosion in India: Water, Wind and Coastal

Water Erosion: Splash, Sheet, Rill and Gully Stages

Water erosion begins whenever rain falls faster than the soil can absorb it. If the soil is saturated, or the rainfall rate is greater than the rate at which water can infiltrate, surface runoff occurs, and runoff with enough energy carries soil with it. Rainfall and the runoff it produces cause four types of water erosion, which also form a sequence from the least to the most severe:

  1. Splash erosion: The impact of a falling raindrop makes a small crater in bare soil and throws soil particles into the air. It is the first and least severe stage.
  2. Sheet erosion: Water flows as a sheet over a large area down a slope and washes away the topsoil. Because the loss is spread evenly, it can continue unnoticed while the topsoil is lost.
  3. Rill erosion: The flow gathers into small concentrated paths, shallow channels no more than a few centimetres deep, which carry soil off the hillslope.
  4. Gully erosion: Running water cuts through the soil and makes deep channels called gullies, metres to tens of metres in depth and width. Land cut by gullies becomes unfit for cultivation and is known as badland.
Four stages of water erosion in order: 1 splash erosion, where a raindrop strikes bare soil and throws particles up, remedied by mulch; 2 sheet erosion, where a thin sheet of water removes the topsoil evenly, remedied by contour ploughing; 3 rill erosion, where flow gathers in channels a few centimetres deep, remedied by bunds and terraces; 4 gully erosion, with channels metres deep that turn farmland into badland, remedied by check dams in series.

Gully Erosion and the Chambal Ravines

Gully erosion reaches its extreme in the Chambal basin, where land cut by deep gullies is called ravines. The Chambal rises near Mhow in the Malwa plateau of Madhya Pradesh, flows north through a gorge to Kota in Rajasthan, and passes Sawai Madhopur and Dholpur before it joins the Yamuna. The river is famous for this badland topography, and the ravines of Chambal, Bhind and Morena are among the best-known examples of the complex relief of ravines and gorges on the north-western Peninsular plateau.

A ravine is larger than a gully but smaller than a valley, and its sides are steep, on the order of 20 to 70 per cent in gradient. The Chambal badlands spread across northern Madhya Pradesh, south-eastern Rajasthan and southern Uttar Pradesh, and a small strip of badlands is also found in western Uttar Pradesh and Haryana; Garbeta in West Bengal is another badland, lying in a monsoon climate. Ravine thorn forest is the natural vegetation of the Chambal ravines.

Ravine land is classed with barren and wasteland, land that normally cannot be brought under cultivation with the available technology, and reforestation is being tried in the Garbeta badlands. Check dams built in series across the channels slow the water that deepens them.

Wind Erosion and Aeolian Processes in Arid Western India

The removal of loose soil from flat or sloping land by the wind is called wind erosion. It is most severe in arid areas and in times of drought, the conditions of India's arid west. Wind erosion is one of the aeolian processes, the work done by wind, and it acts in three ways:

  • Deflation: The wind lifts and removes dust and smaller particles from the surface. Where it keeps blowing in one direction it scoops out shallow depressions called deflation hollows.
  • Abrasion: Sand and silt carried by the wind act as tools that wear down the land surface.
  • Impact: Sand driven against a rock surface strikes it with the sheer force of its momentum, much as in sand-blasting.

The wind moves loosened grains in three ways. Larger, heavier particles slide or roll along the ground by surface creep; particles lifted a short height bounce across the surface by saltation; and very small, light particles rise into suspension and are often carried long distances in dust storms. Saltation accounts for most wind erosion, about 50 to 70 per cent, followed by suspension at 30 to 40 per cent and surface creep at 5 to 25 per cent. Silty soils are the most affected, because silt particles are easily detached and carried away.

Wind erosion is a major source of land degradation, desertification, harmful airborne dust and crop damage, especially where human activity has raised it far above natural rates. Desertification is the gradual degradation of fertile land into arid desert through natural processes and human activities, as in India's arid west. Its immediate cause is the loss of most vegetation, and over-grazing is one of the main reasons for land degradation in Gujarat, Rajasthan, Madhya Pradesh and Maharashtra. Once grazing and drought have stripped the cover, deflation carries off the finer particles and the loose sand drifts across the land.

Wind erosion in two bands. How the wind erodes. Deflation lifts dust and fine particles and scoops deflation hollows; abrasion by wind-borne sand and silt wears down the surface; impact of sand strikes rock, much as in sand-blasting. How the wind moves the grains. Surface creep, large grains rolling along the ground, 5 to 25 per cent; saltation, grains bouncing across the surface, 50 to 70 per cent; suspension, fine particles carried far in dust storms, 30 to 40 per cent. Shelter belts of trees calm the wind and hold the soil.

Coastal and Stream-Bank Erosion

Coastal erosion is the loss of land and the removal of sediment and rock along the coastline by waves, currents, tides and storms. Waves striking a cliff break it by hydraulic action, the force of the water itself, and wear it down by abrasion with the sand and rock particles they carry. Sea level rise caused by climate change will increase coastal erosion worldwide and change low-lying coastal areas significantly, and a cyclone's storm surge adds to the erosion of low-lying coasts.

Coasts are protected by hard and soft means. Soft measures such as sandbags and beach nourishment only slow erosion for a time, while seawalls and groynes are semi-permanent structures, with an average life of about 50 to 100 years for a seawall and 30 to 40 years for a groyne. Mangrove forests and coral reefs are natural defences. Mangrove swamps protect coastal areas from erosion, storm surge and tsunamis, because their massive root systems dissipate wave energy. India conserves mangroves through the Central Sector Scheme on Conservation and Management of Mangroves and Coral Reefs under the National Coastal Mission, which prepares an annual Management Action Plan for mangroves in every coastal State and Union Territory.

Along rivers, bank erosion wears away the banks of a stream, as distinct from scour, which changes its bed. A larger flow of water through a stream causes a large increase in the rate of bank erosion. On the Chambal, bank erosion has cut ravines back into the farmland beside the river.

Causes of Soil Erosion in India: Natural Factors and Human Activities

Natural Factors: Heavy Rainfall, Steep Slopes and Soil Type

Natural forces such as running water, wind and glaciers cause soil erosion, and three conditions favour it. The first is heavy or intense rainfall. In wetland farming regions, where rainfall exceeds the soil-moisture needs of crops during the rainy season, farms face flood and soil erosion hazards. The second is a steep slope, down which water runs off fast; hill farmers cut terraces to break the flow. The third is soil type. Laterite soils are prone to erosion and degradation because of their position on the landscape, and silty soils are the ones the wind removes most easily.

Climate change is raising the natural rate. Warmer air is expected to bring a more vigorous water cycle with more extreme rainfall, and greater rainfall amounts and intensities are expected to cause greater soil erosion. Floods and erosion also feed each other, since flood waters carry eroded material when soil erosion in the catchment is high.

Human Causes: Deforestation, Over-Grazing, Mining and Faulty Farming

Human activities have not only degraded land directly but have also quickened the natural forces that damage it. The main human causes are:

  • Deforestation: Removing the tree cover exposes soil to rain and wind. In Jharkhand, Chhattisgarh, Madhya Pradesh and Odisha, deforestation due to mining has caused severe land degradation. Unsustainable extraction of fuelwood and fodder, encroachment on forest land and forest fires add to the loss.
  • Over-grazing: Livestock strip the ground cover that holds the soil. India supports about 20 per cent of the world's livestock and about 17 per cent of its people on 2.5 per cent of the world's geographical area, which puts enormous pressure on the country's finite land.
  • Shifting cultivation: Plots are cleared, often by slash-and-burn, farmed for a short time and then left fallow to regenerate; in India this farming is called jhumming. It is one of the recognised factors of land degradation.
  • Faulty farming: Ploughing up and down a slope forms channels for the quick flow of water. Improper crop rotation, the failure to adopt soil conservation measures and the indiscriminate use of fertilisers and pesticides weaken the soil further.
  • Mining and quarrying: Mining sites are abandoned after excavation, leaving deep scars and traces of overburden. Grinding limestone for cement and calcite and soapstone for ceramics releases dust that settles on land and slows the infiltration of water into the soil.
  • Construction and urban growth: Construction strips the ground of its cover, and roads and urban sprawl are among the strongest human causes of erosion.
Map of India by the main cause of land degradation. Mining with deforestation in Jharkhand, Chhattisgarh and Odisha; over-grazing in Gujarat, Rajasthan and Maharashtra; Madhya Pradesh under both; over-irrigation and salinity in Punjab and Haryana. Lettered regions: A Chambal ravines, B the Thar with wind erosion, C western Uttar Pradesh with waterlogging.

Effects of Soil Erosion on Farms, Rivers and Reservoirs

Soil erosion removes the topsoil, the upper layer of the soil, and the nutrients that crops draw from it. The soil India loses each year carries away about 0.8 million tonnes of nitrogen, 1.8 million tonnes of phosphorus and 26.3 million tonnes of potassium.

The damage spreads beyond the field. The loss of soil reduces cropland and its production potential, and land cut into gullies goes out of cultivation altogether as badland. Eroded soil washed into streams lowers the quality of surface water, damages drainage networks, lowers the effective water levels of reservoirs and adds to flooding, and the loss of soil destroys habitat as well.

Bar chart of the nutrients India loses each year with eroded soil, in million tonnes. Nitrogen 0.8, phosphorus 1.8, potassium 26.3.

Soil Degradation in India Beyond Erosion

Salinisation, Alkalinity and Waterlogging in Irrigated Tracts

Irrigated land degrades in a different way from hill slopes. In Punjab, Haryana and western Uttar Pradesh, over-irrigation causes waterlogging, the saturation of soil with water for much of the time so that its air space is restricted and roots suffer, and waterlogging raises the salinity and alkalinity of the soil. A large tract of agricultural land has lost its fertility through alkalisation, salinisation and waterlogging, a direct result of a faulty strategy of irrigation and agricultural development.

Salts are a natural part of soils. Drainage water flushes them out where rain or irrigation is sufficient, but they can rise through capillarity and accumulate near the surface under intense evaporation, and human practices such as irrigation increase the salinity of soils. The ions responsible for salinisation are sodium, potassium, calcium, magnesium and chloride.

Soil Acidity, Nutrient Depletion and Chemical Pollution

Soil acidity is a second chemical form of degradation. Laterite soils, formed by intense leaching under heavy rain, are acidic, with a pH below 6.0, and are generally deficient in plant nutrients. Acidification increases with acid rain, intensive agriculture and pollution, and it is reduced by applying lime, organic amendments such as straw and manure, and biochar; in sugarcane, soybean and maize grown on acidic soils, liming has raised the pH and restored nutrients.

Intensive cropping also degrades the soil chemically. Excessive use of insecticides and pesticides has left them in toxic amounts in the soil profile. In irrigated areas, leguminous crops have been pushed out of the cropping pattern and fallows shortened by multiple cropping, so natural fertilisation through nitrogen fixation has been lost. Industrial effluents discharged as waste have become a major source of land and water pollution in many parts of the country.

Desertification and Land Degradation Atlas of India: Extent and State-wise Data

India measures its degraded land with the Desertification and Land Degradation Atlas of India, published by the Space Applications Centre of the Indian Space Research Organisation at Ahmedabad. The edition released on 17 June 2021 gives the State-wise area of degraded land for 2018‑19 and analyses the change over 15 years, from 2003‑05 to 2018‑19.

The atlas puts land degradation and desertification in the country at 97.84 million hectares in 2018‑19. Its State-wise data help plan and carry out restoration schemes, and they give the baseline and technical inputs for the national action plan to meet India's restoration targets. An online portal built with the Space Applications Centre shows the degraded land together with the processes causing degradation.

Soil Conservation Methods in India

Mechanical Methods on Slopes: Contour Ploughing, Bunding, Terracing and Check Dams

Mechanical methods change the shape of the land so that water moves slowly enough to soak in instead of carrying soil away. They suit sloping land, where runoff is fastest:

  • Contour ploughing: Ploughing along the contour lines, across the slope rather than up and down it, makes each furrow a small barrier that slows the flow of water down the slope. Furrows along the contour reduce the formation of rills and gullies during heavy rain and give water more time to settle into the soil.
  • Contour bunding: Lines of stones or bunds are placed along the contours of a slope, so that each one holds back the runoff from the strip above it. It is a method for sloping farmland.
  • Terracing: Steps are cut out of the slope to make level terraces. Terraced fields decrease both erosion and surface runoff, and the western and central Himalaya have well-developed terrace farming.
  • Check dams: A small dam built across a gully, swale or drainage channel counteracts erosion by reducing the velocity of the water. Check dams are usually built as a series at regular intervals along the channel.

Biological Methods: Strip Cropping, Mulching, Crop Rotation and Afforestation

Biological and agronomic methods protect soil by keeping it covered and binding it with roots:

  • Strip cropping: A large field is divided into strips, and strips of grass are left to grow between the crops. The grass breaks the force of the wind and slows water; closely sown crops such as hay, wheat or other forages are usually alternated with row crops, and on badly eroded patches some strips carry permanent protective vegetation.
  • Mulching: A layer of material, normally 5 centimetres or more deep, is spread on the soil surface to prevent erosion on slopes and conserve soil moisture.
  • Crop rotation: Growing different crops in sequence improves soil structure and organic matter, which reduces erosion. Including leguminous crops restores natural fertilisation through nitrogen fixation.
  • Afforestation: Trees on degraded land give soil a permanent cover. The National Forest Policy of 1988 sets a national goal of at least one-third of the land area under forest or tree cover, and among its aims are checking soil erosion and the extension of desert lands, reducing floods and droughts, and increasing forest cover through social forestry and afforestation on degraded land.

Methods for Arid Lands: Shelter Belts, Sand Fences and Dune Stabilisation

Arid land needs methods that defeat the wind rather than running water. A shelter belt, or windbreak, is a planting of one or more rows of trees or shrubs that gives shelter from the wind and protects soil from erosion. Shelter belts have contributed significantly to the stabilisation of sand dunes and of the desert in western India.

Three further methods are used in dry areas. Sand fences control the drifting of soil and sand. Thorny bushes grown on sand dunes stabilise them, and control of over-grazing lets the natural cover return.

Remedies Matched to Each Form of Soil Degradation

Each form of erosion and degradation needs its own remedy. Land damaged by mining and industry is treated by control of mining activities, the proper discharge and disposal of industrial effluents after treatment, and the management of wastelands.

Table 1. Soil erosion and degradation problems in India and the methods that answer each
Erosion or degradation problem Where it is most serious in India Methods that answer it
Sheet and rill erosion on slopes Sloping farmland and hill slopes Contour ploughing, contour bunding, strip cropping, mulching
Gully erosion and ravines Chambal basin, western Uttar Pradesh and Haryana Check dams in series across the channels
Wind erosion and moving sand Thar and the arid west Shelter belts, sand fences, thorny bushes on dunes, grazing control
Mining and industrial damage Jharkhand, Chhattisgarh, Madhya Pradesh, Odisha Control of mining, treatment of effluents before disposal, management of wastelands
Waterlogging and salinity Punjab, Haryana, western Uttar Pradesh Control of over-irrigation, drainage to flush out salts
Coastal erosion Low-lying coasts and deltas Mangroves, seawalls and groynes

Watershed Management: Treating the Whole Catchment

In its narrow sense, watershed management is the efficient management and conservation of surface water and groundwater. It prevents runoff and stores and recharges groundwater through percolation tanks, recharge wells and similar works. In its broad sense it covers the conservation, regeneration and judicious use of all the resources of a watershed, its land, water, plants and animals and its people, and it aims at a balance between natural resources and society. Its success depends largely on community participation.

Treatment of a watershed follows the flow of water from ridge to valley. Trees and grass on the upper slopes slow the rain where it falls; contour bunds and terraces on the farmed slopes hold the runoff; check dams in the drainage lines slow what still flows; and percolation tanks and ponds at the foot store it and recharge the wells below. Because erosion control and water harvesting are the same works, a treated watershed both keeps its soil and gains water for irrigation in the dry months, which matters most in drought-prone and semi-arid regions.

Several Indian programmes show the method at work. Haryali, a watershed development project sponsored by the Central Government and executed by Gram Panchayats with people's participation, was designed to enable rural people to conserve water for drinking, irrigation, fisheries and afforestation. Neeru-Meeru (Water and You) in Andhra Pradesh and Arvary Pani Sansad in Alwar, Rajasthan, built percolation tanks, dug-out ponds (johads) and check dams through people's participation.

In Ralegan Siddhi, a village of Ahmadnagar (now Ahilyanagar) district in Maharashtra, the work began with a percolation tank that villagers repaired by voluntary labour, after which the seven wells below it filled in summer; open grazing was banned in favour of stall-feeding, sugarcane was given up, and pulses, oilseeds and other crops needing little water were encouraged.

Cross-section of a watershed from the ridge on the left to the stream on the right, with five treatments: 1 ridge, trees and grass slow the rain; 2 upper slope, contour bunds hold the runoff; 3 farmed slope, terraces and contour ploughing; 4 drainage line, check dams slow the stream; 5 valley floor, percolation tank and recharge well.

Soil Conservation Policy in India: Schemes and Institutions

Watershed Development Component of PMKSY, Formerly IWMP

The national programme for treating rainfed and degraded land is the Watershed Development Component of the Pradhan Mantri Krishi Sinchayee Yojana (WDC‑PMKSY), run by the Department of Land Resources. Its forerunner, the centrally sponsored Integrated Watershed Management Programme (IWMP), ran from 2009‑10 and was amalgamated into WDC‑PMKSY in 2015‑16. The Pradhan Mantri Krishi Sinchayee Yojana itself was launched on 1 July 2015 to expand assured irrigation, improve on-farm water efficiency and promote water conservation, and the Union Budget for 2026‑27 allocated ₹6,587 crore to it.

The component aims to improve the productive potential of rainfed and degraded land through integrated watershed management, to strengthen community institutions for livelihoods and watershed sustainability, and to make projects more efficient through cross-learning. It restores land through water harvesting structures, protective irrigation and plantation, including afforestation and horticulture. Newer projects also diversify the watershed economy through integrated farming systems, with horticulture, afforestation, fisheries, animal husbandry, apiculture and sericulture, and rejuvenate springs by treating springsheds.

The Government allowed the component to continue as WDC‑PMKSY 2.0 on 15 December 2021 for the project period from 2021‑22 to 2025‑26, which ended in March 2026, with a physical target of 49.50 lakh hectares and an indicative Central outlay of ₹8,134 crore. The unit cost of a project was raised from ₹12,000 to ₹22,000 a hectare in plain areas and from ₹15,000 to ₹28,000 a hectare in difficult and Left Wing Extremism areas. Since 2016‑17, watershed development under PMKSY has received ₹12,432.09 crore in central assistance and has benefited 13.4 lakh farmers (as reported in June 2026).

National Mission for Sustainable Agriculture and the Soil Health Card

Launched in 2014‑15, the National Mission for Sustainable Agriculture is one of the eight missions of the National Action Plan on Climate Change. It promotes sustainable farming through better soil health, efficient water use and climate-resilient practices, and it gives farmers financial help to adopt soil management and water conservation measures. One of its parts is Rainfed Area Development. From 2014‑15 to July 2026, ₹2,119.84 crore was released under Rainfed Area Development, covering 8.50 lakh hectares and benefiting 14.35 lakh farmers through integrated farming systems.

Chemical degradation is the target of the Soil Health Card scheme, which Prime Minister Narendra Modi introduced on 19 February 2015 at Suratgarh in Rajasthan to help State Governments issue soil health cards to all farmers. A card reports the soil's status on 12 parameters (nitrogen, phosphorus, potassium and sulphur; zinc, iron, copper, manganese and boron; and pH, electrical conductivity and organic carbon) and recommends the fertiliser dose and soil amendment the farm needs. The scheme was merged into the Rashtriya Krishi Vikas Yojana from 2022‑23 as its Soil Health and Fertility component, and 25.89 crore Soil Health Cards had been generated by 13 March 2026.

Afforestation Schemes: Green India Mission, National Afforestation Programme and CAMPA

Afforestation schemes restore the cover that protects soil on a large scale. The National Mission for a Green India is one of the missions of the National Action Plan on Climate Change; it aims at protecting, restoring and enhancing India's forest cover through planting in forest and non-forest areas, and its activities started in 2015‑16. It focuses on increasing and improving forest and tree cover, including on degraded lands, and is part of India's commitment under its Nationally Determined Contribution to create an additional carbon sink of 2.5 to 3.0 billion tonnes of carbon dioxide equivalent by 2030.

For degraded forests, the Ministry of Environment, Forest and Climate Change ran the National Afforestation Programme, a centrally sponsored scheme for regenerating degraded forests and adjoining areas through people's participation, from 2000 through the National Afforestation and Eco-development Board. It was run in a decentralised way, through the State Forest Development Agency at the State level, the Forest Development Agency at the forest division level and Joint Forest Management Committees in the villages.

By February 2022 the Ministry had approved the merger of the National Afforestation Programme into the Green India Mission, and by August 2023 the two ran as a single scheme. Compensatory afforestation funded through the Compensatory Afforestation Fund Management and Planning Authority (CAMPA) has also been used to increase forest cover across the country.

Table 2. India's main schemes for soil and land conservation
Scheme or mission Ministry or department Began What it does for soil
Watershed Development Component of PMKSY (earlier IWMP) Department of Land Resources IWMP 2009‑10; merged into PMKSY 2015‑16; WDC‑PMKSY 2.0 approved 15 December 2021 for 2021‑22 to 2025‑26 Treats rainfed and degraded watersheds with water harvesting, plantation and protective irrigation
National Mission for Sustainable Agriculture Ministry of Agriculture and Farmers Welfare 2014‑15 Funds soil health, water-use efficiency and rainfed area development
Soil Health Card Ministry of Agriculture and Farmers Welfare 19 February 2015; part of the Rashtriya Krishi Vikas Yojana from 2022‑23 Tests soil on 12 parameters and recommends balanced fertiliser use
National Mission for a Green India Ministry of Environment, Forest and Climate Change Activities from 2015‑16 Protects, restores and enhances forest and tree cover, including on degraded land

Land Degradation Neutrality and India's 26 Million Hectare Target

India's national targets sit within the United Nations Convention to Combat Desertification (UNCCD), adopted in Paris on 17 June 1994 and the only internationally legally binding framework set up to address desertification; it has 197 parties. Its aim is written into Target 15.3 of the Sustainable Development Goals, which asks countries by 2030 to restore degraded land and soil and to strive for a land degradation-neutral world. Land degradation neutrality needs two things together, avoiding new land degradation and restoring degraded land.

India has committed to achieve land degradation neutrality by 2030. At the climate conference in Paris in 2015, India joined the voluntary Bonn Challenge with a pledge to restore 13 million hectares of degraded and deforested land by 2020 and 8 million hectares more by 2030. India hosted the fourteenth Conference of the Parties of the UNCCD in September 2019, and the pledge of 21 million hectares by 2030 was raised there to 26 million hectares. The Green India Mission, which now includes the National Afforestation Programme, and the Watershed Development Component of PMKSY contribute to this target.

Worldwide, the fifteenth Conference of the Parties, held from 9 to 20 May 2022, agreed to restore one billion hectares of degraded land by 2030.

Institutions for Soil Survey and Conservation Research

Several national institutions supply the science behind these schemes. The ICAR-Indian Institute of Soil and Water Conservation at Dehradun develops technologies for soil conservation, water harvesting and watershed management.

The Soil and Land Use Survey of India runs the Nationwide Soil Resource Mapping project, which combines satellite imagery with field observations to build village-level soil inventories for land use planning and crop choice. By September 2024 about 29 million hectares had been mapped, against a target of 142 million hectares of agricultural land, and ₹1,076 crore was provided to six States (Uttar Pradesh, Madhya Pradesh, Rajasthan, Maharashtra, Tamil Nadu and Andhra Pradesh) to speed the work.

Previous Year UPSC‑CSE Questions

Each Prelims question is explained option by option, and each Mains question comes with an answer outline.

  1. UPSC Prelims 2014In India, the problem of soil erosion is associated with which of the following?
    1. Terrace cultivation
    2. Deforestation
    3. Tropical climate

    Select the correct answer using the code given below.

    1. a 1 and 2 only
    2. b 2 only
    3. c 1 and 3 only
    4. d 1, 2 and 3
    How to approach this Prelims question

    Question type: Select from a list

    Approach: Test each item by asking whether it causes erosion or prevents it.

    • Statement 1: Terrace cultivation cuts steps into a slope so that water is held back, and terrace cultivation restricts erosion; it is a remedy, so it is wrong.
    • Statement 2: Deforestation removes the cover that protects soil from rain and wind, and in Jharkhand, Chhattisgarh, Madhya Pradesh and Odisha deforestation due to mining has caused severe land degradation; it is correct.
    • Statement 3: A tropical climate is not in itself a cause; its heavy rain erodes soil where the cover has been removed, so statement 3 is not correct.

    Only statement 2 is associated with the problem, which is option (b).

    Trap to watch: Terrace cultivation is seen on eroded hill slopes, so students who link the place with the problem mark it as a cause, when the terraces are there to stop the erosion.

    Why each option is right or wrong:

    • (a) 1 and 2 only: Wrong. Terrace cultivation restricts erosion, so statement 1 cannot be a cause.
    • (b) 2 only: Correct. Deforestation exposes the soil to rain and wind, while terracing checks erosion and a tropical climate is not in itself a cause.
    • (c) 1 and 3 only: Wrong. It leaves out deforestation, the one true cause, and includes the remedy and the climate type.
    • (d) 1, 2 and 3: Wrong. Statements 1 and 3 are not causes of erosion.

    Answer: (b) 2 only. Deforestation removes the protective cover of the soil, whereas terrace cultivation restricts erosion.

  2. UPSC Prelims 2014What are the benefits of implementing the 'Integrated Watershed Development Programme'?
    1. Prevention of soil runoff
    2. Linking the country's perennial rivers with seasonal rivers
    3. Rainwater harvesting and recharge of groundwater table
    4. Regeneration of natural vegetation

    Select the correct answer using the code given below.

    1. a 1 and 2 only
    2. b 2, 3 and 4 only
    3. c 1, 3 and 4 only
    4. d 1, 2, 3 and 4
    How to approach this Prelims question

    Question type: Select from a list

    Approach: Ask whether each benefit comes from treating one watershed.

    • Statement 1: Watershed management prevents runoff, so it stops soil being carried away; correct.
    • Statement 2: Linking perennial rivers with seasonal rivers joins different river basins, while a watershed programme treats one catchment; wrong.
    • Statement 3: Percolation tanks, recharge wells and check dams store rainwater and recharge groundwater; correct.
    • Statement 4: Plantation, afforestation and the regeneration of natural resources are part of watershed treatment; correct.

    Only statements 1, 3 and 4 are benefits, which is option (c).

    Trap to watch: River linking is also a water project, so students who think of watershed work as water work in general include statement 2, when a watershed programme stays inside one catchment.

    Why each option is right or wrong:

    • (a) 1 and 2 only: Wrong. It includes river linking and leaves out water harvesting and the regeneration of vegetation.
    • (b) 2, 3 and 4 only: Wrong. It includes river linking and leaves out the prevention of soil runoff, the first aim of watershed treatment.
    • (c) 1, 3 and 4 only: Correct. Stopping runoff, harvesting rainwater with groundwater recharge, and regenerating vegetation are all achieved within one watershed.
    • (d) 1, 2, 3 and 4: Wrong. Linking perennial and seasonal rivers moves water between basins and is not a benefit of watershed development.

    Answer: (c) 1, 3 and 4 only. A watershed programme stops runoff, recharges groundwater and restores vegetation within one catchment, while river linking moves water between basins.

  3. UPSC Prelims 2013Contour bunding is a method of soil conservation used in
    1. a desert margins, liable to strong wind action
    2. b low flat plains, close to stream courses, liable to flooding
    3. c scrublands, liable to spread of weed growth
    4. d None of the above
    How to approach this Prelims question

    Question type: Single correct answer

    Approach: Ask what problem a contour bund solves. A bund built along a contour holds back water running down a slope, so it is a method for sloping land. Desert margins suffer from wind, which shelter belts, sand fences and thorny bushes on dunes answer, so option (a) does not fit. Low flat plains have no slope for a contour bund to work across, and their flooding needs drainage and flood control, so option (b) does not fit. Weed growth in scrubland is not a problem of runoff at all, so option (c) does not fit. Since none of the three places is where contour bunding is used, the answer is option (d).

    Trap to watch: Option (a) tempts students who know that bunds hold soil and assume they work against wind too, when contour bunding acts on water running down a slope.

    Why each option is right or wrong:

    • (a) desert margins, liable to strong wind action: Wrong. Wind erosion is checked by shelter belts, sand fences and dune planting; a contour bund acts on runoff down a slope.
    • (b) low flat plains, close to stream courses, liable to flooding: Wrong. Flat land has no slope across which to build contour bunds, and flooding needs drainage and flood control.
    • (c) scrublands, liable to spread of weed growth: Wrong. Weed growth is not a runoff problem, so a contour bund does not address it.
    • (d) None of the above: Correct. Contour bunding is used on sloping farmland, which none of the three options describes.

    Answer: (d) None of the above. Contour bunding holds back runoff on sloping land, and none of the places listed is sloping land.

  4. UPSC Prelims 2010With reference to soil conservation, consider the following practices:
    1. Crop rotation
    2. Sand fences
    3. Terracing
    4. Wind breaks

    Which of the above are considered appropriate methods for soil conservation in India?

    1. a 1, 2 and 3 only
    2. b 2 and 4 only
    3. c 1, 3 and 4 only
    4. d 1, 2, 3 and 4
    How to approach this Prelims question

    Question type: Select from a list

    Approach: Match each practice to the problem it solves.

    • Crop rotation: It improves soil structure and organic matter, which reduces erosion; correct.
    • Sand fences: They control the drifting of soil and sand in dry areas; correct.
    • Terracing: Steps cut into a slope decrease erosion and surface runoff, as in the western and central Himalaya; correct.
    • Wind breaks: Rows of trees or shrubs shelter the soil from the wind and protect it from erosion, as the shelter belts of western India do; correct.

    All four are appropriate methods, which is option (d).

    Trap to watch: Crop rotation looks like a farming choice made for yield rather than a conservation method, so students drop it and pick option (b), but better soil structure and organic matter make the soil harder to erode.

    Why each option is right or wrong:

    • (a) 1, 2 and 3 only: Wrong. It leaves out wind breaks, which shelter the soil from wind erosion.
    • (b) 2 and 4 only: Wrong. It keeps only the methods against wind and leaves out crop rotation and terracing, which also conserve soil.
    • (c) 1, 3 and 4 only: Wrong. It leaves out sand fences, which control drifting sand and soil in dry areas.
    • (d) 1, 2, 3 and 4: Correct. Crop rotation, sand fences, terracing and wind breaks each check a form of erosion found in India.

    Answer: (d) 1, 2, 3 and 4. Crop rotation strengthens the soil, terracing checks runoff on slopes, and sand fences and wind breaks check wind erosion.

  5. UPSC Prelims 2001Identify the correct order of the processes of soil erosion from the following:
    1. a Splash erosion, Sheet erosion, Rill erosion, Gully erosion
    2. b Sheet erosion, Splash erosion, Gully erosion, Rill erosion
    3. c Rill erosion, Gully erosion, Sheet erosion, Splash erosion
    4. d Gully erosion, Rill erosion, Sheet erosion, Splash erosion
    How to approach this Prelims question

    Question type: Correct sequence

    Approach: Order the stages by how concentrated the flowing water becomes. A raindrop first loosens the soil where it strikes, so splash erosion comes first. The loosened soil is then carried off by an even sheet of water, which is sheet erosion. The sheet gathers into small channels, the rills, and the rills deepen and widen into gullies. The order is splash, sheet, rill and gully, which is option (a).

    Trap to watch: Students who know that sheet erosion removes topsoil over a wide area often put it first, but the raindrop has to detach the particles before any sheet of water can carry them.

    Why each option is right or wrong:

    • (a) Splash erosion, Sheet erosion, Rill erosion, Gully erosion: Correct. Detachment by raindrops comes first, and the flowing water then concentrates from a sheet into rills and finally gullies.
    • (b) Sheet erosion, Splash erosion, Gully erosion, Rill erosion: Wrong. Splash erosion detaches the soil before sheet flow can move it, and rills form before they deepen into gullies.
    • (c) Rill erosion, Gully erosion, Sheet erosion, Splash erosion: Wrong. It puts channel erosion before the stages that loosen and spread the soil, which is the reverse of how runoff develops.
    • (d) Gully erosion, Rill erosion, Sheet erosion, Splash erosion: Wrong. It gives the stages in exactly reverse order; the gully is the last and most severe stage.

    Answer: (a) Splash erosion, Sheet erosion, Rill erosion, Gully erosion. Water erosion begins with the raindrop's splash, spreads as sheet flow, gathers into rills and ends as gullies.

  6. UPSC Mains 2026 GS‑IDiscuss the role of aeolian processes in desertification and land degradation.
    Answer outline

    The outline sets out what the question asks, the main arguments, relevant examples and the direction of the conclusion; it is not a full model answer.

    Directive verb: Discuss

    Introduction: Aeolian processes are the erosion, transport and deposition of material by wind, and they are most effective in arid areas and in times of drought, where bare, dry soil meets strong winds.

    Body (sub-themes to develop):

    • Erosion by wind: Deflation lifts dust and fine particles and leaves deflation hollows, abrasion wears the surface with wind-borne sand, and impact strikes rock like sand-blasting.
    • Transport: Surface creep, saltation and suspension; saltation does about 50 to 70 per cent of wind erosion, and suspended dust travels long distances in dust storms; silty soils are the most easily removed.
    • Degradation that results: Loss of fine particles from farmland, crop damage, airborne dust and moving sand; wind erosion is a major source of land degradation and desertification.
    • Human trigger: Over-grazing strips the cover in Gujarat, Rajasthan, Madhya Pradesh and Maharashtra, and drought then lets the wind work; land degradation and desertification covered 97.84 million hectares in 2018‑19.
    • Remedies: Shelter belts, which have stabilised sand dunes and the desert in western India; sand fences; thorny bushes on dunes; and control of grazing.

    Conclusion: Wind does not create desertification on its own but completes the damage that over-use begins, so restoring the plant cover and breaking the wind's force are the two keys to reversing it.

  7. UPSC Mains 2019 GS‑IIIElaborate the impact of National Watershed Project in increasing agricultural production from water-stressed areas.
    Answer outline

    Directive verb: Elaborate

    Introduction: India's national watershed programmes, run today as the Watershed Development Component of the Pradhan Mantri Krishi Sinchayee Yojana, aim to improve the productive potential of rainfed and degraded land through integrated watershed management.

    Body (sub-themes to develop):

    • More water for crops: Water harvesting structures and groundwater recharge allow protective irrigation of rainfed crops through dry spells.
    • Soil kept on the farm: Contour bunds, terraces and check dams stop the loss of topsoil and the nutrients it holds.
    • Diversified production: Integrated farming systems with horticulture, afforestation, fisheries, animal husbandry, apiculture and sericulture widen farm incomes.
    • Scale: WDC‑PMKSY 2.0 set a physical target of 49.50 lakh hectares for 2021‑22 to 2025‑26, and watershed development has benefited 13.4 lakh farmers since 2016‑17.
    • Limits: Results depend on community institutions that maintain the works, which is why the programme strengthens community-based local institutions.

    Conclusion: Watershed development raises production in water-stressed areas by keeping both water and soil on the land, and its gains last where the community owns the works.

  8. UPSC Mains 2016 GS‑IIn what way micro-watershed development projects help in water conservation in drought-prone and semi-arid regions of India?
    Answer outline

    Directive verb: None (an in what way question)

    Introduction: Watershed management is the efficient management and conservation of surface water and groundwater through works that prevent runoff and store and recharge water, and a micro-watershed project applies it to a small catchment together with its community.

    Body (sub-themes to develop):

    • Holding rain where it falls: Trees and grass on the ridge, contour bunds and terraces on the slopes, and contour ploughing slow runoff and let water soak in.
    • Storage and recharge: Check dams, percolation tanks, dug-out ponds (johads) and recharge wells store water and raise the groundwater table, as the seven wells below Ralegan Siddhi's repaired tank showed.
    • Soil conserved with water: The same works stop the loss of topsoil, so the land keeps its moisture and fertility.
    • Community participation: Haryali through Gram Panchayats, Neeru-Meeru in Andhra Pradesh and Arvary Pani Sansad in Alwar built structures with people's participation; Ralegan Siddhi banned open grazing and gave up sugarcane for crops needing little water.
    • National support: WDC‑PMKSY treats rainfed and degraded land through water harvesting structures, protective irrigation and plantation.

    Conclusion: Micro-watershed projects conserve water in drought-prone and semi-arid regions because they combine small structures with the community that maintains them, so success depends as much on people's participation as on engineering.

Sources

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