Understanding Desertification Processes: Wind, Water, and Chemical Deterioration

India is losing productive land at an alarming rate. Nearly 97.85 million hectares – close to 30% of the country’s total geographical area – is currently undergoing some form of land degradation. Behind this number are several distinct yet interconnected processes: wind erosion, water erosion, soil salinity, and waterlogging. Each process operates differently, targets different regions, and demands unique interventions. Understanding how these desertification processes work is the first step toward addressing them effectively.

Wind erosion: the silent reshaping of arid India 🔗

Wind erosion is among the most visually dramatic processes of desertification. It occurs when strong, persistent winds displace fine soil particles from the surface, stripping land of its topsoil and depositing sand elsewhere. In India, this process affects approximately 10.46 million hectares in the hot arid regions, primarily across Rajasthan, Haryana, Gujarat, and Punjab. Around 68% of the approximately 28,600 sq. km affected area is covered by sand dunes and sandy plains – landscapes that are in a constant state of flux.

How wind erosion works 🔗

Wind erosion operates through three main mechanisms. Saltation involves medium-sized soil particles bouncing along the surface. Suspension lifts finer particles into the air, sometimes transporting them hundreds of kilometres. Surface creep pushes larger grains along the ground. Together, these mechanisms gradually strip away topsoil and bury adjacent fertile land under layers of sand.

The problem is particularly acute in western Rajasthan, where the Thar Desert is expanding as strong summer winds plough through agricultural fields that have been stripped of vegetative protection. Deforestation worsens the situation – trees serve as natural windbreaks, and their removal accelerates dune migration. Wind erosion accounted for roughly 5.46% of the total desertification area in India, making it the third-most significant driver of land degradation after water erosion and vegetation loss.

Beyond the Thar: coastal and cold deserts 🔗

Wind erosion is not limited to Rajasthan’s hot deserts. Coastal areas with sandy plains are also affected, where onshore winds constantly redistribute sediment. The cold desert regions of Leh in Jammu & Kashmir face a similar challenge – frost shattering breaks rocks into fine particles that are then picked up by strong Himalayan winds. These varied geographies show that wind erosion is a pan-Indian problem, not just a western India issue.

Water erosion: India’s most destructive land degradation process 🔗

While wind erosion captures attention in arid zones, water erosion is the single most damaging process of desertification in India. It affects approximately 107.1 million hectares – a staggering area that makes it responsible for more land degradation than all other processes combined. According to the Desertification and Land Degradation Atlas of India published by ISRO’s Space Applications Centre, water erosion contributed to nearly 11% of all desertified land in the country during 2011-13.

Sheet erosion, gullies, and ravines 🔗

Water erosion occurs in several forms. Sheet erosion happens when rainfall uniformly strips a thin layer of topsoil across a wide area – it is subtle but cumulatively devastating. Rill erosion creates small channels as water concentrates into streams. When left unchecked, rills deepen into gullies, and over time these gullies expand into ravines – deep, eroded valleys that render land entirely unusable for agriculture.

The Chambal region, which stretches across parts of Madhya Pradesh, Rajasthan, and Uttar Pradesh, is a classic example. Intensive water erosion has carved extensive badlands and ravines, making vast tracts of land completely unproductive. The Saurashtra and Kutchh uplands in Gujarat and the eastern margins of the Thar Desert in Rajasthan are other hotspots where water erosion is particularly active.

Why water erosion is so severe in India 🔗

India’s rainfall patterns play a key role. Intense, short bursts of monsoon rainfall hit land that often has sparse vegetation cover, causing rapid surface runoff. This runoff carries away the nutrient-rich topsoil – the very layer that supports plant growth. The result is a vicious cycle: erosion reduces vegetation, and reduced vegetation further increases erosion. Terrain deformation through ravines and gullies permanently alters the landscape, often beyond any easy restoration.

Soil salinity and alkalinity: the invisible poison in productive plains 🔗

Unlike wind and water erosion, which physically move soil, salinity and alkalinity degrade land through chemical deterioration. Large areas across the productive Indo-Gangetic plain – spanning Haryana, Punjab, Uttar Pradesh – along with coastal regions of Gujarat have lost significant agricultural productivity due to this process.

What happens in salt-affected soils 🔗

Salt-affected soils in India broadly fall into two categories: saline soils (with excess soluble salts) and sodic soils (with high levels of exchangeable sodium). According to a study published in Frontiers in Sustainable Food Systems, about 6.73 million hectares in India are salt-affected, with roughly 2.35 million hectares of that occurring in the Indo-Gangetic plains alone. The majority of sodic soils – around 3.77 million hectares – are concentrated in this region.

When sodium accumulates on the soil’s exchange complex, the physical properties of the soil deteriorate sharply. The soil becomes hard and compact when dry, and sticky and impermeable when wet. Infiltration rates drop, meaning water cannot penetrate the surface, and plant roots cannot access moisture or nutrients. Crop yields decline dramatically – in some cases by 40% or more.

What drives salinity build-up 🔗

Several factors accelerate this process. Irrigation with carbonate-rich groundwater is a major contributor – as water evaporates, it leaves behind dissolved salts that accumulate in the topsoil over successive crop seasons. Runoff from adjoining undrained basins also carries salts into productive fields. In areas with poor drainage, a rising water table brings salts from deeper soil layers to the surface through capillary action. When this water evaporates during the dry season, salt deposits are left behind on the topsoil, visible as white efflorescence – the telltale sign of a salinized landscape.

The introduction of canal irrigation without adequate drainage infrastructure has been a major driver. The Sharda Sahayak Canal Command region in Uttar Pradesh saw salinization of around 0.37 million hectares within three decades. Similarly, the Indira Gandhi Nahar Priyojana (IGNP) region in Rajasthan lost approximately 0.18 million hectares to salinization within just a few years of the project’s introduction.

Waterlogging: when too much water becomes the problem 🔗

Waterlogging is the opposite of what one might expect from desertification – yet it is a recognized and serious process of land degradation. It occurs when the water table rises to a level that saturates the root zone of plants, depriving them of oxygen and eventually killing them. In India, waterlogging affects approximately 8.52 million hectares of land surface.

The Indira Gandhi Canal: a case study in unintended consequences 🔗

The most severe waterlogging in India has been documented in the Indira Gandhi Canal Command Area in Rajasthan. This canal – the longest irrigation canal in India at 650 km – was built to bring water to the Thar Desert and transform barren land into productive agricultural fields. And it succeeded in that goal. However, excess irrigation on soils with gypsum-rich barriers and the absence of adequate drainage planning created an entirely new set of problems.

The soils in the IGNP region contain complex layers of sand, clay, and impervious kankar (calcium carbonate nodules) that act as barriers, preventing water from percolating to deeper levels. Combined with the lack of natural surface drainage – the region has no functional rivers – excess irrigation water has nowhere to go. The water table has risen sharply, and in many areas now sits just one metre below the surface, well above the safe limit of 0.51 metres originally planned for Phase I of the project.

The consequences are severe. Rising water brings dissolved salts to the surface, creating saline-sodic conditions and forming hard salt-rich pans. Around 50% of the IGNP command area has experienced waterlogging. Estimates suggest that roughly 49.6% of the monitored area is at risk of becoming waterlogged. India loses between 1.2 to 2.0 million tonnes of food grain production annually due to waterlogging, according to World Bank estimates – a significant blow to a country striving for food security.

Why waterlogging and salinity are a combined threat 🔗

Waterlogging and salinity are deeply interconnected. When water stagnates in fields due to poor drainage, evaporation leaves behind salt deposits. This secondary salinization reduces soil fertility even further. The cycle is self-reinforcing: waterlogging causes salinity, salinity reduces crop growth, reduced crop growth means less water uptake by plants, and less water uptake worsens waterlogging. Breaking this cycle requires a combination of engineering solutions (such as subsurface drainage) and biological approaches (such as planting salt-tolerant tree species that can lower the water table through transpiration).

The economic cost of desertification processes 🔗

The combined impact of these four processes is not merely ecological – it carries enormous economic weight. A TERI study conservatively estimated the annual cost of land degradation in India at approximately USD 48.8 billion, equivalent to roughly 2.5% of GDP. This figure includes losses from reduced agricultural productivity, damaged water resources, and diminished ecosystem services. Water erosion alone accounts for about 14% of the total economic loss, while vegetation degradation – often a precursor to erosion – accounts for over 55%.

For a country where millions depend directly on agriculture for their livelihoods, these are not abstract numbers. Degraded land means lower yields, lower incomes, greater food insecurity, and ultimately, rural-to-urban migration as farming families can no longer sustain themselves.

The way forward: addressing multiple processes simultaneously 🔗

Because these desertification processes are interconnected – wind erosion strips topsoil that water erosion then washes away, poor irrigation causes both salinity and waterlogging – solutions must be equally integrated. India has committed under the UN Convention to Combat Desertification (UNCCD) to restore 26 million hectares of degraded land by 2030. Programmes like the National Mission for Green India, the Desert Development Programme, and watershed development schemes all target specific aspects of the problem.

On the technology front, ISRO’s satellite-based monitoring through the Desertification and Land Degradation Atlas provides critical data for tracking changes over time. Techniques like dune stabilization, micro-irrigation, subsurface drainage for waterlogged areas, and biodrainage using tree species like Eucalyptus and Prosopis are being deployed across affected regions. However, scaling these interventions to match the enormous extent of degradation – nearly 98 million hectares – remains the central challenge.

What do you think? Given that India’s most ambitious irrigation projects have sometimes worsened land degradation through waterlogging and salinity, how should we balance the need for irrigation expansion with sustainable land management? And in your region, have you noticed signs of any of these desertification processes at work?

References

1. https://www.drishtiias.com/daily-news-analysis/land-degradation-and-desertification-in-india
2. https://www.sciencedirect.com/science/article/pii/S2590061723000303
3. https://ruralindiaonline.org/hi/library/resource/desertification-and-land-degradation-atlas-of-india/
4. https://www.indiawaterportal.org/agriculture/farm/desertification-not-just-north-indian-problem
5. https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2020.533781/full
6. https://www.researchgate.net/publication/369959145_Emerging_Issues_and_Problems_of_Soil_Salinity_and_Water_Logging_A_Case_Study_of_Indira_Gandhi_Canal_Rajasthan
7. https://www.teriin.org/sites/default/files/2018-04/Vol%20I%20-%20Macroeconomic%20assessment%20of%20the%20costs%20of%20land%20degradation%20in%20India_0.pdf