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TOPIC INFO – UGC NET (Geography)
SUB-TOPIC INFO – Geography of Economic Activities & Regional Development (UNIT 6)
CONTENT TYPE – Detailed Notes
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1. Weaver’s Method of Crop combination Region
1.1. Introduction
1.2. Concept of Crop Combination
1.3. Theoretical Basis of Weaver’s Method
1.4. Formula Used in Weaver’s Method
1.5. Procedure
1.6. Significance of Weaver’s Method
1.7. Limitations of Weaver’s Method
2. Doi’s Method of Crop Combination
2.1. Introduction
2.2. Meaning of Crop Combination
2.3. Theoretical Basis of Doi’s Method
2.4. Formula Used in Doi’s Method
2.5. Procedure
2.6. Merits of Doi’s Method
2.7. Limitations of Doi’s Method
2.8. Comparison with Other Methods
3. Rafiullah’s Maximum Positive Deviation Method
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Methods for Delineation of Crop Combination Regions (Weaver, Doi and Rafiullah)
UGC NET GEOGRAPHY
Geography of Economic Activities & Regional Development (UNIT 6)
Weaver’s Method of Crop combination Region
Introduction
Weaver’s Method of Crop Combination is a quantitative statistical technique used in agricultural geography to identify and delineate crop combination regions. It was proposed by J.C. Weaver (1954) to overcome the limitations of earlier descriptive and subjective methods of regionalization. The method provides an objective, mathematical basis for determining which crops dominate an area and how many crops together form a meaningful agricultural combination.
The central idea of Weaver’s method is that no agricultural region is monocultural in reality; instead, regions are characterized by combinations of crops grown together. The method identifies the most representative set of crops for a region by comparing actual crop percentages with an idealized theoretical distribution.
Concept of Crop Combination
A crop combination refers to a group of crops that collectively occupy the largest proportion of cultivated land in a given area. Instead of focusing on a single dominant crop, Weaver emphasized understanding multiple crop dominance, which better reflects real agricultural landscapes influenced by climate, soil, irrigation, technology, and socio-economic factors.
For example, a region may not be purely “wheat-growing” but rather a wheat–rice–pulses combination region.
Theoretical Basis of Weaver’s Method
Weaver assumed that in a perfectly uniform system:
A single crop region would occupy 100% of cultivated land
A two-crop combination would have 50% + 50%
A three-crop combination would have 33.33% each
A four-crop combination would have 25% each, and so on
The actual crop percentages of a region are compared with these theoretical values. The best crop combination is the one where the deviation between actual and theoretical values is minimum.
Formula Used in Weaver’s Method
The deviation is calculated using the least deviation formula:
$$D\;=\;{\textstyle\textstyle\frac{\sum_{}{(X_i\;-\;T_i)}^2}n}$$
Where:
D = Deviation value
Xi = Actual percentage of the crop
Ti = Theoretical percentage of the crop
n = Number of crops in the combination
The combination with the lowest value of D is selected as the true crop combination of the region.