WORLD A — LAND, AGRICULTURE & FARMING FOUNDATIONS · REALM 04
Land Degradation
Soil Erosion & Desertification · Salinisation & Waterlogging · Mining-Induced Degradation (36 Micro-Realms)
ECONOMIC GEOGRAPHY
→
REALM 03: LAND CAPABILITY
→
VEGETATIVE & HYDROLOGIC STRESS
→
EROSION & DESERTIFICATION
→
SALINISATION & WATERLOGGING
→
MINING & INDUSTRIAL SCARS
SUB-WORLD I — SOIL EROSION MECHANICS & GEOMORPHIC LOSS
Fluvial, Aeolian & Gravity Processes (04.01 – 04.09)
MICRO-REALM 04.01
Splash Erosion Detachment
- Raindrop kinetic impact
- Soil aggregate shattering
- Surface pore crusting
Sheet Erosion
- Uniform overland flow
- Invisible A-horizon skimming
- Fertile colloid wash-off
Rill Erosion
- Concentrated micro-runoff
- Finger-like shallow grooves
- Obliterated by normal tillage
Gully Erosion & Ravines
- Headward waterfall cutting
- Non-tillable deep chasms
- Chambal-Yamuna badland belt
Bank & Coastal Erosion
- Lateral river toe-undercutting
- Riparian farmland slumping
- Littoral wave abrasion
Aeolian Wind Erosion
- Saltation (50–75% transport)
- Surface creep & suspension
- Deflation hollow blowouts
Soil Loss Equation (USLE)
- A = R × K × LS × C × P
- Rainfall erosivity (R)
- Cover (C) & practice (P)
Mass Wasting & Slumps
- Shear stress exceeding strength
- Himalayan & Western Ghats
- Debris flows & rotational slumps
Cryogenic & Glacial Loss
- Freeze-thaw frost shattering
- Periglacial solifluction lobes
- Cold-desert Ladakh stripping
SUB-WORLD II — DESERTIFICATION & DRYLAND DEGRADATION
UNCCD Framework & Biophysical Decline (04.10 – 04.18)
MICRO-REALM 04.10
UNCCD Dryland Spectrum
- Arid, semi-arid, dry sub-humid
- P/PET ratio 0.05 to 0.65
- Climatic + human co-drivers
Vegetative Degradation
- Deforestation & fuelwood felling
- Canopy-root anchor loss
- Leading degradation process (India)
Overgrazing & Trampling
- Livestock exceeding carrying limit
- Palatable grass eradication
- Hoof-induced infiltration drop
Aeolian Sand Encroachment
- Mobile barchan & seif dunes
- Thar desert fringe creep
- Aravalli gap wind corridors
Charney Albedo Feedback
- Bare soil high reflectivity
- Atmospheric subsidence cooling
- Convective rainfall suppression
Shortened Jhum Cycles
- Slash-and-burn hill clearing
- Fallow drop from 20 to 3 yrs
- Northeast & Odisha hill loss
Subsurface Plough-Pan
- Heavy tractor disc compaction
- High bulk-density barrier
- Perched water & stunted roots
Soil Nutrient Mining
- Harvest removal > replenishment
- Soil organic carbon (<0.5%)
- Multi-micronutrient Zn/B/Fe deficit
SAC-ISRO Degradation Atlas
- ~29.7% of India TGA degraded
- Water erosion #1 (~11% TGA)
- Rajasthan, Maharashtra, Gujarat top
SUB-WORLD III — SALINISATION, ALKALISATION & WATERLOGGING
Hydrological & Chemical Pathology (04.19 – 04.27)
MICRO-REALM 04.19
Canal Seepage & Rise
- Unlined canal percolation
- Flood irrigation over-application
- Disrupted natural drainage
Root-Zone Waterlogging
- Water table within 2 meters
- Soil pore oxygen expulsion
- Anaerobic root necrosis
Capillary Salt Wick
- Upward capillary moisture pull
- High semi-arid evaporation
- Surface salt crystallization
Primary vs Secondary Salt
- Natural arid parent-rock salt
- Irrigation-induced salinization
- Brackish tubewell groundwater
Saline Soils (Reh / Kallar)
- ECe >4 dS/m; pH <8.5; ESP <15%
- Chlorides & sulfates of Na/Ca/Mg
- Osmotic physiological drought
Sodic Soils (Usar / Karl)
- ESP >15%; pH 8.5–10.0
- Sodium carbonate clay dispersion
- Impervious columnar structure
Coastal Seawater Intrusion
- Freshwater aquifer over-pumping
- Ghyben-Herzberg interface shift
- Saurashtra & Kuttanad ingress
Command-Area Pathology
- Indira Gandhi Canal (IGNP) belt
- SW Punjab & Haryana Sem-nallahs
- Paddy-wheat water-table paradox
Chemical & Acid Stress
- Urea-induced soil acidification
- Pesticide & herbicide persistence
- Earthworm & mycorrhizal die-off
SUB-WORLD IV — MINING-INDUCED & INDUSTRIAL DEGRADATION
Extractive Scars & Toxic Contamination (04.28 – 04.36)
MICRO-REALM 04.28
Open-Cast Pit Excavation
- Complete forest-soil scalping
- Inverted lithological profile
- Chota Nagpur & Odisha belts
Overburden Spoil Dumps
- Sterile crushed waste rock
- Zero organic matter or microbes
- Steep slope gullying & siltation
Subsidence & Coal Fires
- Unfilled mine-gallery collapse
- Jharia & Raniganj seam fires
- Surface fissures & toxic fumes
Acid Mine Drainage (AMD)
- Sulfide/pyrite air-water oxidation
- Sulfuric acid pH <3 runoff
- Solubilized Fe, Al, Mn toxicity
Tailings & Heavy Metals
- Ore-beneficiation slurry dams
- Pb, Hg, Cd, Cr, As leaching
- Jaduguda & Kolar tailings risk
Rat-Hole & Sand Mining
- Meghalaya coal rat-hole pits
- Riverbed sand-mining incision
- Alluvial water-table drop
Brick-Kiln Topsoil Loss
- 1–2 meter A/B-horizon excavation
- Peri-urban Class I soil destruction
- Thermal & black-carbon fallout
Fly-Ash & Industrial Sludge
- Thermal power ash-pond breaches
- Tannery (Cr) & dye (Tiruppur)
- Cement-dust foliar & soil crust
Degradation Hotspots Matrix
- Chambal, Thar, IGNP, Punjab
- Chota Nagpur, Jaintia, Western Ghats
- Aral Sea & Sahel global analogs
Core Ontological Distinctions
Land Degradation vs. DesertificationLand Degradation is the loss of biological or economic productivity of land in any climatic zone (including humid rainforests or alluvial plains). Desertification (UNCCD definition) is specifically land degradation occurring in arid, semi-arid, and dry sub-humid areas ($0.05 \le \text{P/PET} \le 0.65$).
Saline Soils (White Alkali) vs. Sodic/Alkaline Soils (Black Alkali)Saline soils have excess neutral soluble salts ($\text{EC}_e > 4\text{ dS/m}$, $\text{pH} < 8.5$, $\text{ESP} < 15\%$), keep flocculated structure, and are reclaimed by freshwater leaching. Sodic soils have excess exchangeable sodium ($\text{ESP} > 15\%$, $\text{pH } 8.5\text{–}10.0$), dispersed impermeable clay, and require gypsum ($\text{CaSO}_4\cdot 2\text{H}_2\text{O}$) chemical replacement.
Sheet Erosion vs. Rill Erosion vs. Gully ErosionSheet erosion removes thin, uniform layers of fertile topsoil invisibly. Rill erosion carves small finger-channels that can still be smoothed out by normal ploughing. Gully erosion carves deep, permanent chasms that farm machinery cannot cross.
The Land Entropy Cascade
How physical, chemical, and extractive stresses destroy natural capital.
INTACT PEDOLOGICAL PROFILE
↓ Deforestation + Overgrazing + Tillage
SPLASH → SHEET → RILL → GULLY
↓ Unlined Canals + Capillary Evaporation
WATERLOGGING & SALINE-SODIC CRUST
↓ Open-Cast Mining + Industrial Leachate
BIOLOGICAL COLLAPSE & WASTELAND