The need for growing more food, on a sustainable basis, to support the ever-increasing population demands a systematic appraisal of our natural resources including climate, soils, flora, and fauna. Since agriculture is highly location-specific, grouping the available land area in the country into different agro-ecological regions based on certain identifiable characteristics becomes all the more important. This may help the country to engage in more rational planning and optimizing resource use for the present and in preserving them for the future.
An agro-climatic zone is a land unit in terms of major climates, suitable for a certain range of crops and cultivars. An ecological region is an area of the earth’s surface characterized by distinct ecological responses to macro-climate, as expressed by soils, vegetation, fauna, and aquatic systems (FAO, 1983). Several attempts have been made to delineate major agro-ecological regions in respect to soils, climate, physiography and natural vegetation for macro-level planning on a more scientific basis. Some of the important ones are : A. Agro-ecological regions by the ICAR.
B. Agro-climatic regions by the Planning Commission. C. Agro-climatic zones under NARP. D. Agro-ecological regions by the NBSS & LUP. A. Agro-ecological regions by the ICAR As a result of the second major reorganization which the ICAR underwent in 1973, the country has been divided into eight major agro-ecological regions for more meaningful planning of agricultural research and development. They are : 1. Humid Western Himalayan Region 2. Humid Bengal – Assam Basin 3. Humid Eastern Himalayan Region and Bay Islands 4. Sub-humid Sutlej-Ganga Alluvial Plains 5.
Sub-humid to Humid Eastern and South-eastern Uplands 6. Arid Western Plains 7. Semi-arid Lava Plateau and Central Highlands 8. Humid to Semi-arid Western Ghats and Karnataka Plateau These regions consist of large geographical area of land having major groups of geological formations, physiography, climate, soils, vegetation, land use and cropping patterns. Some of the essential features of these regions are described here. 1. Humid Western Himalayan Region : It consists of Jammu and Kashmir, Himachal Pradesh and two hill divisions of Uttar Pradesh, namely, Kumaon and Garhval.
It is characterized by high mountains and narrow valleys. The climate varies from hot and sub-humid tropical in the South to temperate cold arid in the North, with the rainfall ranging from 8 cm in Ladakh to over 100 cm in Jammu area. It has sandy loam mountain meadow, loamy and acidic sub-montane, and loamy brown hill soils. Nearly half of the area is under forest, and horticulture including sericulture supplements agriculture. Rich forest wealth and range lands are the assets of this region. Degradation of forests is the major problem. 2.
Humid Bengal-Assam Basin : It covers West Bengal and Assam representing the Ganga-Brahmaputra alluvial plain. It is characterized by semi-stabilized sand dunes on alluvial terraces, lateritic remnants in the West, and numerous creeks and swamps in the deltaic tract. It experiences hot humid monsoonal climate, and the rainfall ranges from 220 to 400 cm. The predominant soil groups are alluvial, red and brown hill. Rich forests in Assam and fertile deltas in West Bengal are the assets. Frequent floods in Assam and extensive occurrence of saline patches in the deltaic tracts are the major constraints. . Humid Eastern Himalayan Region and Bay Islands : It includes Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura, Meghalaya, and Andaman & Nicobar Islands. It consists of the Eastern Himalayan and the Arakan Ranges with a wide range of elevation. The rainfall ranges from 200 to 400 cm. The major soil groups are brown hill, red and yellow, alluvial, and acidic laterites. It is endowed with rich evergreen forests. Animal husbandry and pisciculture have great potential. Major liability is shifting cultivation leading to deforestation and soil erosion. 4.
Sub-humid Sutlej-Ganga Alluvial Plains : It comprises Punjab, plains of Uttar Pradesh, Delhi, and Bihar. The entire region is level, except for the Tarai-Bhabar tract. It experiences extremes of climate, with very hot summer and very cold winter. The rainfall ranges from 30 to 200 cm. The major soil groups are calcareous sierozem, reddish chestnut, alluvial, and patches of saline and alkali soils. The soils are highly disturbed in Bihar due to frequent floods. Major area is under cultivation. Generally, the region is double cropped. Flooding, salinity, alkalinity, and erosion are the major problems. . Sub-humid to Humid Eastern and South-eastern Uplands : It encompasses Orissa, Andhra Pradesh and the Raipur Division of Madhya Pradesh. It is characterized by undulating topography, denuded hills, plateau, river valleys, and high lands. The climate is tropical monsoonal, and sub-humid to humid from West to East. The rainfall ranges from 100 to 180 cm. Major soil groups are mixed black, red and yellow, red sandy, laterite, black, and alluvial soils. Rich forest wealth is an asset, and shifting cultivation, soil salinity and acidity are the major constraints. 6.
Arid Western Plains : It includes Haryana, Rajasthan, Gujarat, and Dadra & Nagar Haveli. It is characterized by extensive alluvial plain dotted with sand dunes, saline depressions and granite hills. The rainfall is scanty, ranging from 10 to 65 cm and erratic. Major soil groups are alluvial, black, desert, saline and alkaline. Nearly one-third of the area is under cultivation. Frequent dry spells, salinity and alkalinity are the major problems. 7. Semi-arid Lava Plateau and Central Highlands : It covers Maharashtra, Goa, Daman & Diu, and Western and Central Madhya Pradesh. It is predominantly a plateau region.
The climate is semi-arid with extremes of temperature, and the rainfall ranges from 70 to 125 cm except in the Western Ghats where it varies from 330 to 750 cm. Major soil groups are alluvial, black, laterite, mixed red and black, and yellowish brown. More than half of the area is cultivated. Frequent drought is the major problem in the region. 8. Humid to Semi-arid Western Ghats and Karnataka Plateau : It consists of Karnataka, Tamil Nadu, Kerala, Pondicherry, and Lakshadweep Islands. The physiographic features are Western Ghats, plateau, river valleys, undulating rocky plains, and coastal plains.
The western ghats is humid and the rest of the area is semi-arid. The rainfall ranges from 60 to 300 cm. Major soil groups are black, red, lateritic, and alluvial. Rich forest wealth and Western Ghats suitable for plantation crops are the main assets. Dry farming is prevalent and a considerable area is irrigated through wells, tanks and rivers. Salinity, alkalinity, erosion, and acidity are the major problems. B. Agro-climatic regions by the Planning Commission : The Planning Commission, as a result of the mid-term appraisal of the lanning targets of the Seventh Plan, has divided the country into fifteen broad agro-climatic zones based on physiography, soils, geological formation, climate, cropping patterns, and development of irrigation and mineral resources for broad agricultural planning and developing future strategies. These include : 1. Western Himalayan Region 2. Eastern Himalayan Region 3. Lower Gangetic Plains Region 4. Middle Gangetic Plains Region 5. Upper Gangetic Plains Region 6. Trans-Gangetic Plains Region 7. Eastern Plateau & Hills Region 8. Central Plateau & Hills Region 9.
Western Plateau & Hills Region 10. Southern Plateau & Hills Region 11. East Coast Plains & Hills Region 12. West Coast Plains & Ghats Region 13. Gujarat Plains & Hills Region 14. Western Dry Region 15. The Islands Region C. Agro-climatic zones under NARP The country has been divided into 131 agro-climatic zones, under the World Bank supported National Agricultural Research Project (NARP) of the ICAR, essentially based on climate, soils, and existing cropping patterns of each State as a unit. The zones identified are : a. Andhra Pradesh b. Assam 1. Krishna Godavari Zone 2. North Coastal Zone . Southern Zone 4. Northern Telangana Zone 5. Southern Telangana Zone 6. Scarce Rainfall Zone of Rayalaseema 7. High Altitude and Tribal Zone1. North Bank Plains Zone 2. Upper Brahmaputra Valley Zone 3. Central Brahmaputra Valley Zone 4. Lower Brahmaputra Valley Zone 5. Barak Valley Zone 6. Hills Zone c. Bihar d. Gujarat 1. North-west Alluvial Plain Zone 2. North-east Alluvial Plain Zone 3. South Bihar Alluvial Plain Zone 4. Central and North-eastern Plateau Zone 5. Western Plateau Zone 6. South-eastern Plateau Zone1. South Gujarat Heavy Rainfall Zone 2. South Gujarat Zone 3.
Middle Gujarat Zone 4. North Gujarat Zone 5. North-west Zone 6. North Saurashtra Zone 7. South Saurashtra Zone 8. Bhal and Coastal Zone e. Haryana f. Himachal Pradesh 1. Eastern Zone 2. Western Zone1. Sub-montane and Low-hills Sub-tropical Zone 2. Mid-hills Sub-humid Zone 3. High-hills Temperate West Zone 4. High-hills Temperate Dry Zone g. Jammu and Kashmirh. Karnataka 1. Sub-tropical Zone 2. Intermediate Zone 3. Temperate Zone 4. Cold Arid Zone1. North-east Transition Zone 2. North-east Dry Zone 3. Northern Dry Zone 4. Central Dry Zone 5. Eastern Dry Zone 6. Southern Dry Zone . Southern Transition Zone 8. Northern Transition Zone 9. Hill Zone 10. Coastal Zone i. Kerala j. Madhya Pradesh 1. Northern Zone 2. Southern Zone 3. Central Zone 4. High Altitude Zone 5. Problem Areas Zone1. Chattisgarh Plain Zone 2. Bastar Plateau Zone 3. North Hill Zone of Chattisgarh 4. Kymore Plateau and Satpura Hill Zone 5. Vindhya Plateau Zone 6. Central Narmada Valley Zone 7. Gird Zone 8. Bundelkhand Zone 9. Satpura Plateau Zone 10. Malwa Plateau Zone 11. Nirmar Valley Zone 12. Jhabua Hills Zone k. Maharashtral. North-eastern Hill Region 1. South Konkan Coastal Zone . North Konkan Coastal Zone 3. Western Ghat Zone 4. Sub-montane Zone 5. Western Maharashtra Plain Zone 6. Scarcity Zone 7. Central Maharasthra Plateau Zone 8. Central Vidarbha Zone 9. Eastern Vidarbha Zone1. Alpine Zone 2. Temperate Sub-alpine Zone 3. Sub-tropical Hill Zone 4. Sub-tropical Zone (Valley) 5. Mild-tropical Hill Zone 6. Mild-tropical Plain Zone m. Orissa n. Punjab 1. North-western Plateau Zone 2. North-central Plateau Zone 3. North-eastern Coastal Plain Zone 4. East and South-eastern Coastal Plain Zone 5. North-eastern Ghat Zone 6. Eastern Ghat High Land Zone 7.
South-eastern Ghat Zone 8. Western Undulating Zone 9. West-central Table Land Zone 10. Mid-central Table Land Zone1. Sub-montane Zone 2. Undulating Plain Zone 3. Central Plain Zone 4. Western Plain Zone 5. Western Zone o. Rajasthan p. Tamil Nadu 1. Arid Western Plain Zone 2. Irrigated North-western Plain Zone 3. Transitional Plain Zone of Inland Drainage 4. Transitional Plain Zone of Luni Basin 5. Semi-arid Eastern Plain Zone 6. Flood Prone Eastern Plain Zone 7. Sub-humid Southern Plain and Aravalli Hills Zone 8. Southern Humid Plain Zone 9. South-eastern Humid Plain Zone1.
North-eastern Zone 2. North-western Zone 3. Western Zone 4. Cauvery Delta Zone 5. Southern Zone 6. High Rainfall Zone 7. High Altitude and Tribal Zone q. Uttar Pradeshr. West Bengal 1. Hill Zone 2. Bhabar and Tarai Zone 3. Western Plain Zone 4. Mid-western Plain Zone 5. South-western Semi-arid Zone 6. Central Plain Zone 7. Bundelkhand Zone 8. North-eastern Plain Zone 9. Eastern Plain Zone 10. Vindhyan Zone1. Hill Zone 2. Tarai Zone 3. Old Alluvial Zone 4. New Alluvial Zone 5. Laterite and Red Soil Zone 6. Coastal Saline Soil Zone s. Union Territories : 1. Pondicherry – 2 Zones 2.
Andaman & Nicobar Islands – 3 Zones. These zones have been identified based on a comprehensive research review of each State. The identification of these zones for the purposes of developing location-specific research and development strategies to increase agricultural production is a significant step taken towards regionalizing agricultural research in the country. D. Agro-ecological Regions by the NBSS & LUP Since all the above mentioned approaches use State as a unit for subdivision, many zones having similar agro-climatic characteristics but occurring in different States have been created.
Moreover, adequate attention was not paid in these approaches to soils which is the country’s most important agricultural resource. In order to overcome these lacunae, the National Bureau of Soil Survey & Land Use Planning (NBSS & LUP) has recently brought out a 21-zone agro-ecological regional map of the country, essentially based on physiography, soils, bio-climatic types, and growing period which influences the supply of water for plant growth. This map is essentially based on 50 years data of over 350 meteorological stations and up-to-date soils database available in the country.
The agro-ecological regions identified are : I. Arid Ecosystem : 1. Western Himalayas, Cold Arid Ecoregion with Shallow Skeletal Soils : The region covers 4. 7% of the land area mainly in the Districts of Ladakh and Gilgit. It has mild summers and severe winters, with mean annual temperature and rainfall of less than 8° C and 150 mm, respectively. The annual growing period is less than 90 days. While the Northern part is covered under permanent snow, the valley areas show skeletal and calcareous soils. It has great potential for growing dry fruits like apricot and flowers like roses in valleys. 2.
Western Plain, Hot Arid Ecoregion with Desert and Saline Soils : It covers 9% of the land area in the Western Rajasthan, South-western Haryana and Punjab, Kutch Peninsula and Northern Kathiawar Peninsula. It has hot summers and cool winters, with an annual rainfall of less than 300 mm and growing period of less than 90 days. The soils are sandy and saline. Rainfed agriculture is the traditional practice. Drought and salinity are the major constraints. 3. Deccan Plateau, Hot Arid Ecoregion with Mixed Red and Black Soils : It includes the Districts of Raichur and Bellary of Karnataka, and Anantapur of Andhra Pradesh covering 1. % of the land area. It is characterized by hot and dry summers and mild winters, with an annual rainfall ranging from 400 to 500 mm. The growing period is less than 90 days. The soils are shallow to medium red loamy and deep clayey black. Rainfed farming is most common. Prolonged dry spells and soil erosion are the major problems. II. Semi-arid Ecosystem : 4. Northern Plain and Central Highlands, Hot Semi-arid Ecoregion with Alluvium – derived Soils : It occupies 10% of the land area covering part of northern plain, central highlands and Gujarat plain.
It has hot and dry summers and cool winters, with rainfall varying between 400 and 800 mm. The growing period ranges from 90 to 150 days. Soils are loamy and the terrain is interspersed by sand dunes. Rainfed farming is common, with intensive cultivation in areas irrigated through tube wells. Imperfect drainage leading to salinity and lowering of ground water due to over-exploitation are the major constraints. 5. Central (Malwa) Highlands and Kathiawar Peninsula, Hot Semi-arid Ecoregion with Medium and Deep Black Soils : It covers 5. % of the land area in the Western Madhya Pradesh, Eastern Rajasthan and Gujarat States. It has hot and dry summers and mild winters, with rainfall ranging from 600 to 900 mm. The growing period ranges from 90 to 150 days. Soils are loamy to clayey deep black. Dry farming is the common practice. Frequent dry spells, imperfect drainage, salinity and alkalinity are the major constraints. 6. Deccan Plateau, Hot Semi-arid Ecoregion with Shallow and Medium (Inclusion of Deep) Black Soils :It includes most of Maharashtra and Northern part of Karnataka and Andhra Pradesh covering 10% of the land area.
It has hot summers and mild winters, with rainfall ranging from 600 to 1000 mm. The growing period ranges from 90 to 150 days. It is characterized by medium to deep black soils. Rainfed agriculture is the traditional practice and prolonged dry spells adversely affect crop growth. The area has high productivity potential under judicious irrigation with watershed – based management. 7. Deccan Plateau and Eastern Ghats, Hot Semi-arid Ecoregion with Red and Black Soils : It covers part of the Deccan Plateau and Eastern Ghats in the State of Andhra Pradesh accounting for 6. % of the land area. It has hot summers and mild winters, with 600 to 1000 mm rainfall and 90 to 150 days growing period. It has medium to heavy red and loamy black cotton soils. Rainfed agriculture is common and rice is cultivated under irrigation. Imperfect drainage, salinity and erosion are the major problems. 8. Eastern Ghats (TN Uplands) and Deccan Plateau, Hot Semi-arid Ecoregion with Red Loamy Soils : It includes Tamil Nadu uplands and Western Karnataka covering 6. 9% of land area. It has hot and dry summers and mild winters, with a rainfall of 600 to 1000 mm.
The growing period varies from 120 to 150 days. Rainfed agriculture is common and rice is grown under irrigation. Erosion and dought due to coarse soils are the major problems. III. Sub-humid Ecosystem : 9. Northern Plain, Hot Sub-humid Ecoregion with Alluvium – derived Soils : It covers part of Northern Indo-Gangetic plain occupying 3. 7% of the land area. It is characterized by hot to warm summers and cool winters receiving 1000 to 1200 mm rainfall. The growing period ranges from 150 to 180 days. It has deep loamy alluvial soils. Both rainfed and irrigated agriculture are followed.
Poor water management, waterlogging and salinity are the major problems. 10. Central Highlands (Malwa & Bundelkhand), Hot Sub-humid Ecoregion with Medium and Deep Black Soils : It covers part of the central highlands mainly in the Districts of Arisen, Sager, Bhopal, Sehore, Shajapur and Hoshangabad in Madhya Pradesh. It occupies 2. 5% of the land area. Hot summers and mild winters with 1000 to 1500 mm rainfall and 150 to 180 days growing period are the main features. It has moderately deep black soils. Rainfed and irrigated farming are practiced.
Inundation along major streams and drought during Kharif season are the major problems. 11. Deccan Plateau and Central Highlands (Bundelkhand), Hot Sub-humid Ecoregion with Red and Black Soils : It comprises the Bundelkhand part of Madhya Pradesh and North-eastern part of Vidarbha region covering 4. 2% of the land area. It is characterized by hot summers and mild winters, with 1000 to 1500 mm rainfall. The growing period varies from 150 to 180 days. It has medium red and heavy black soils. Both rainfed and irrigated farming are practised. Cracking clay soils and soil erosion are the major problems. 2. Eastern Plateau (Chattisgarh Region), Hot Sub-humid Ecoregion with Red and Yellow Soils : It constitutes Chattisgarh region of Madhya Pradesh and South-west highlands of Bihar covering 4% of the land area. It is characterized by hot summers and cool winters, with 1200 to 1600 mm rainfall. The growing period ranges between 150 and 180 days. The soils are medium to heavy and non-calcareous. Rainfed farming is common and rice and wheat are grown under irrigation. Severe erosion, partial waterlogging and seasonal drought are the common problems. 13.
Eastern (Chhota Nagpur) Plateau and Eastern Ghats, Hot Sub-humid Ecoregion with Red Loamy Soils : It includes Chhota Nagpur Plateau of Bihar, Western part of West Bengal, Orissa, and Bastar region of Madhya Pradesh covering 8. 5% of the land area. It has hot summers and cool winters, with a rainfall of 1000 to 1600 mm and 150 to 180 days growing period. The soils are red loamy and non-calcareous. Rainfed farming is more common, seasonal drought and severe soil erosion are the major problems. 14. Eastern Plain, Hot Sub-humid with Alluvium – derived Soils : It covers North-eastern Uttar Pradesh and Northern Bihar occupying 2. % of the land area. It has hot summers and cool winters, with 1400 to 1600 mm rainfall. The growing period varies from 180 to 210 days. The soils are mainly alluvium. Rainfed and irrigated farming are practised. Flooding, imperfect drainage and salinity are the major constraints. 15. Western Himalayas, Warm Sub-humid (Inclusion Humid) Ecoregion with Brown Forest and Podzolic Soils : It includes Jammu and Kashmir, Himachal Pradesh and North-western half of Uttar Pradesh covering 5. 4% land area. It has warm sub-humid to cool humid climate, with mild summers and cold winters.
The rainfall ranges from 1600 to 2200 mm and it has 150 to 210 days growing period. The soils are brown forest and podzolic. Agriculture is practised in valleys and terraces. Severe cold, deforestation, land slides, acidity, and imperfect drainage in valleys are the common problems. IV. Humid-Perhumid Ecosystem : 16. Assam and Bengal Plains, Hot Humid (Inclusion Sub-humid) Ecoregion with Alluvium – derived Soils : It comprises the plains of the Brahmaputra and the Ganga rivers, covering parts of Assam and West Bengal and representing . 6% of the land area. It has hot summers and mild to moderately cool winters, with the rainfall ranging from 1400 to 2000 mm. The growing period is more than 270 days. The soils are slightly acidic. Flooding, waterlogging and acidity are the major problems. 17. Eastern Himalayas, Warm Perhumid Ecoregion with Brown Hill Soils : It encompasses Northern Bengal and Assam, and most parts of Arunachal Pradesh and Sikkim covering 2. 4% of the land area. It has mild summers and moderate to severe winters, with a rainfall exceeding 2000 mm.
The growing period is more than 270 days. The soils are loamy brown forest with high organic matter. Shifting cultivation is the traditional farming system followed. It has evergreen forests and faces the problems of deforestation and soil erosion. 18. North-eastern Hills (Purvachal) Warm Perhumid Ecoregion with Red and Lateritic Soils : It constitutes North-eastern hilly States of Nagaland, Meghalaya, Manipur, Mizoram, and South Tripura covering 3. 3% of the land area. It has warm summers and cold winters, with the rainfall ranging from 1600 to 2600 mm.
The growing period exceeds 270 days. The soils are loamy red, yellow, and lateritic with slight acidity. Shifting cultivation is common leading to deforestation and severe erosion. It has tropical moist deciduous forests. V. Coastal Ecosystem : 19. Eastern Coastal Plain, Hot Sub-humid Ecoregion with Alluvium – derived Soils : It covers the Eastern coastal plain extending from Cauvery Delta to Gangetic Delta and occupies 2. 5% of the land area. It has hot summers and mild winters, with an annual rainfall of 1200 to 1600 mm.
The growing period ranges from 150 to 210 days. The soils are mainly clayey with slight acidity. Rainfed and irrigated rice farming are practised. Imperfect drainage and salinity are the major constraints. 20. Western Ghats and Coastal Plains, Hot Humid – Perhumid Ecoregion with Red, Lateritic and Alluvium – derived Soils : It constitutes Western coastal plains of Maharashtra, Karnataka, and Kerala States covering 3% of the land area. It has hot summers, with rainfall exceeding 2000 mm. The growing period is more than 270 days.
It has red, lateritic and alluvial soils. Waterlogging and severe erosion are the major problems. It has high potential for export-oriented plantation crops. VI. Islands Ecosystem : 21. Islands of Andaman-Nicobar and Lakshadweep, Hot Perhumid Ecoregion with Red Loamy and Sandy Soils : It comprises the Andaman and Nicobar Islands in the East and Lakshadweep in the West covering a meager 0. 3% of the land area. The climate is typified by tropical conditions and the rainfall ranges from 1600 to 3000 mm.
The growing period exceeds 270 days. The soils of the Andaman and Nicobar Islands are medium to very deep, red loamy and acidic, and that of the Lakshadweep Islands are highly calcareous and sandy. Most of the area is under forest and the land use is dominated by plantation crops. Forest degradation leading to severe erosion, and inundation of coastal areas leading to saline marshes are the major constraints. It has greater potential for growing sustainable oil palm plantations.