WORLD B — AGRICULTURAL GEOGRAPHY · REALM 10
Agricultural Regionalisation
Agro-Climatic Regions · Crop Regions · Physical & Economic Factors (36 Micro-Realms)
ECONOMIC GEOGRAPHY
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SPATIAL DIFFERENTIATION
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PHYSICAL / ECONOMIC FACTORS
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CROP COMBINATION
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AGRO-CLIMATIC ZONES (15)
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AGRO-ECOLOGICAL ZONES (20)
SUB-WORLD I — DETERMINANTS & FOUNDATIONS
Physical, Economic & Methodological Basis (10.01 – 10.09)
MICRO-REALM 10.01
Concept of Regionalisation
- Delineating contiguous areas
- Internal homogeneity, external heterogeneity
- Macro, meso, micro classification
Climate Determinants
- Temperature limits (Frost, Heat)
- Rainfall amount and variability
- Primary boundary setter for crops
Soil & Topography
- Pedological fertility (Alluvial vs Laterite)
- Slope gradient limiting mechanisation
- Altitude modifying local climate
Market Proximity
- Von Thünen principles
- Perishability dictating location (Dairy/Horticulture)
- Bid-rent curve dynamics
Transport & Infra
- Overcoming distance decay
- Cold chains altering regional limits
- Access to inputs (fertilizer/seeds)
Technological Factors
- Irrigation breaking rainfall limits
- HYV seeds altering maturity periods
- Greenhouse micro-climate creation
Socio-Cultural Factors
- Dietary preferences (Rice vs Wheat)
- Land tenure and inheritance laws
- Traditional ecological knowledge
Quantitative Methods
- Statistical boundary delineation
- Variance, Standard Deviation methods
- Objective, repeatable criteria
Qualitative Methods
- Empirical observation (e.g., Baker, Whittlesey)
- Subjective boundary drawing
- Based on geographer's field experience
SUB-WORLD II — CROP COMBINATION & CONCENTRATION
Statistical Delineation Models (10.10 – 10.18)
MICRO-REALM 10.10
Crop Region Concept
- Area defined by dominant crop(s)
- Reflects optimal physical-economic alignment
- Rarely a strict monoculture boundary
Weaver's Method (1954)
- Minimum deviation from theoretical curve
- Variance: $d^2 / n$
- Highly precise but mathematically tedious
Doi's Method (1959)
- Modification of Weaver's formula
- Uses $\sum d^2$ instead of variance
- Substitutes tedious calculations with tables
Rafiullah's Method (1965)
- Maximum positive deviation method
- Reduces the number of crops in a combination
- Better suited for highly diversified Indian agriculture
Crop Diversification
- Bhatia's Index of Diversification
- Higher index = lower diversification
- Risk buffering vs commercial specialization
Crop Concentration
- Location Quotient (LQ) approach
- Density of a crop in a region vs national average
- Reveals areas of extreme specialization
Monoculture Regions
- Extreme concentration of single crop
- Assam (Tea), Punjab (Wheat/Rice)
- Ecologically vulnerable, economically efficient
Multi-Crop Regions
- High diversification index
- Middle Gangetic Plain, Deccan Plateaus
- Subsistence buffering strategy
Dynamic Shifts
- Crop regions are not static
- Green Revolution shifted rice to Punjab
- Climate change shifting wheat boundaries
SUB-WORLD III — AGRO-CLIMATIC ZONES (I)
Planning Commission 1989 Framework (10.19 – 10.27)
MICRO-REALM 10.19
The 15 Zone Framework
- Initiated in 7th Five Year Plan (1989)
- Based on topography, climate, soil, water
- Move away from purely political state planning
1: Western Himalayan
- J&K, HP, Uttarakhand
- High relief, cold winters, terrace farming
- Horticulture (Apples, Walnuts), Saffron
2: Eastern Himalayan
- Sikkim, NE States, Darjeeling
- High rainfall, rugged topography
- Shifting cultivation, Tea, Bamboo
3: Lower Gangetic Plain
- West Bengal delta region
- High rainfall, alluvial soil, flood-prone
- Rice (multiple crops) & Jute dominance
4: Middle Gangetic Plain
- Eastern UP, Bihar
- Transitional climate, fertile alluvium
- Rice-Wheat system, Maize, Sugarcane
5: Upper Gangetic Plain
- Central/Western UP
- Extensive canal irrigation network
- Wheat, Sugarcane, Dairy concentration
6: Trans-Gangetic Plain
- Punjab, Haryana, Delhi, Rajasthan fringes
- Semi-arid but highly irrigated (Tubewells)
- Green Revolution heartland (Wheat-Rice)
7: Eastern Plateau & Hills
- Chota Nagpur, Chhattisgarh, Odisha inland
- Red/Laterite soils, undulating terrain
- Rainfed rice, millets, tribal agriculture
8: Central Plateau & Hills
- Bundelkhand, Malwa, Rajasthan Aravallis
- Semi-arid, mixed red and black soils
- Millets, Pulses, Oilseeds, Animal husbandry
SUB-WORLD IV — AGRO-CLIMATIC (II) & ECOLOGICAL
Peninsular, Coastal & ICAR Frameworks (10.28 – 10.36)
MICRO-REALM 10.28
9: Western Plateau & Hills
- Maharashtra, MP, Deccan trap
- Deep black regur soils, rainfed
- Cotton, Sugarcane (with irrigation), Jowar
10: Southern Plateau & Hills
- Karnataka, AP, Tamil Nadu inland
- Semi-arid rain-shadow, red soils
- Millets, Pulses, Tank irrigation
11: East Coast Plains
- Coromandel to Utkal coast deltas
- Alluvial soils, cyclonic rainfall
- Intensive rice, aquaculture, tobacco
12: West Coast Plains
- Malabar to Konkan
- High orographic rainfall, laterite soils
- Plantation crops (Spice, Rubber, Coconut)
13: Gujarat Plains & Hills
- Arid to semi-arid transitional
- Black and alluvial soils
- Groundnut, Cotton, Dairy (Amul)
14: Western Dry Region
- Thar Desert (Rajasthan)
- Extreme aridity, sandy soils
- Bajra, Guar, IGNP canal impacts
15: The Island Region
- A&N Islands, Lakshadweep
- Equatorial climate, coral/volcanic
- Coconut, Copra, Marine fisheries
Agro-Ecological Regions
- NBSS&LUP (ICAR) 1992 framework
- 20 major zones (and 60 sub-zones)
- Integrates soil type with bioclimatic factors
Length of Growing Period
- Key metric for ICAR ecological zones
- Days when precip > half potential evapotranspiration
- Determines feasible crop duration
Core Ontological Distinctions
Agro-Climatic vs. Agro-Ecological ZonesAgro-Climatic Zones (Planning Commission, 15 zones) are broad regions delineated primarily by temperature, rainfall, and topography for macro-level planning. Agro-Ecological Regions (NBSS&LUP/ICAR, 20 zones) overlay precise soil groups and the exact "Length of Growing Period" (LGP) to create highly specific biological capability maps for agricultural research.
Weaver's Method vs. Rafiullah's MethodWeaver's Method calculates variance from a theoretical perfect distribution (e.g., 50/50 for a two-crop region); it often results in overly complex, multi-crop combinations in highly diversified India. Rafiullah's Maximum Positive Deviation modifies the formula to reduce the number of crops included, providing a sharper, more practical crop-region boundary.
Trans-Gangetic vs. Upper Gangetic PlainThe Trans-Gangetic Plain (Zone 6: Punjab, Haryana) lies west of the Yamuna, is semi-arid, but achieved extreme productivity via tubewell irrigation. The Upper Gangetic Plain (Zone 5: West/Central UP) is the core Doab, historically reliant on vast canal networks.
The Architecture of Regions
How geographers carve continuous space into discrete functional units.
CLIMATE BASELINE (TEMP/RAIN)
↓ Soil & Topography Constraint
BIOPHYSICAL POTENTIAL
↓ Infra, Market & Tech Input
ACTUAL CROP SELECTION
↓ Statistical Delineation (Weaver/LQ)
AGRICULTURAL REGION DEFINED