Agro-Ecological Regions | Geography Optional for UPSC (Notes) PDF Download

Agro-Ecological Regions

• Agro-ecology refers to the study of agricultural ecosystems and their components as they function in themselves and as a part of the larger ecosystem. Such a study would help in evolving more sustainable agricultural ecosystems.
• It is important to understand the difference between an agro- climatic zone and an agro-ecological zone.
• Agro-climatic zone refers to a land unit in terms of its major climate, superimposed on the length of growing period or moisture availability period; agro-ecological zone is the land unit carved out of agro-climatic zone and superimposed on landform which influences both the climate and length of growing period.
• So study of an agro-ecological zone will involve examining its climate, soil, water, flora and fauna.
• A systematic investigation of the agro-ecological regions, which would be somewhat homogeneous regions in terms of soil, climate and physiographic and conducive moisture availability periods or length of growing period, is extremely important for planning appropriate land use.
• The AER is designed to address the issues related to agricultural production by delineating agriculturally potential areas suitable for particular genotype and is essentially needed for achieving the optimum production potential of a crop and crop variety. AER is capable in delineating agro-ecologically comparable regions for generating and transferring various agro-technologies.
• A study of the country‘s agro-ecological regions is necessary for several reasons such as to determine yield potentialities of different crops, and crop combinations in the agro-ecological regions in the future. It would help in deciding future action in terms of crop diversification. It would determine the best kind of crops to be grown in a piece of land keeping optimization of land use requirements in mind. It aids in spread of knowledge of agricultural research and agro-technology.
• The National Bureau of Soil Survey & Land Use Planning (NBSS&LUP) came up with twenty agro-ecological zones based on the growing period as an integrated criterion of effective rainfall, soil groups, delineated boundaries adjusted to district boundaries with a minimal number of regions. Subsequently, these twenty agro-ecological zones were sub- divided into 60 sub-zones.

Agro-Ecological Regions

Agro-Ecological Regions of India

1. Western Himalayas, Cold Arid Eco-Region:

• It represents the area of the north-western Himalayas, covering Ladakh and Gilgit districts with an area of 15.2 m ha, occupying 4.7 per cent of the total geographical area (329 m ha) of the country.
• This region is characterized by mild summer and severe winter with mean annual temperature of less than 8°C and mean annual rainfall of less than 150 mm.
• The area qualifies for acidic soil moisture and cryic soil temperature regime with LGP of less than 90 days in a year.
• The skeletal and calcareous soils occur on gently sloping to almost level valleys. They are alkaline in reaction and low to medium in organic matter content.
• The higher northern part of the plateau remains under permanent snow cover. The eco-region shows sparse forest trees. The major part of cultivated area is under vegetables.
• Apple and apricot are the major fruit crops grown in the area.
• Among the livestock, mule dominates, while sheep, goat and yak stand next in order.
• This zone is known for grazing (by pashmina goats).
• Constraints
  • Severe climatic conditions, especially cryic temperature regime which acts as a thermal pan for plant growth.
  • Narrow crop growing period limits agriculture to valleys during thawing period which coincides with the scanty rains.
  • Shallow, sandy and gravelly/boulder soils.
  • Moderately to highly calcareous nature of soils which poses nutrient imbalance for normal crop production.

2. Western Plain, Kachchh And Part Of Kathiawar Peninsula, Hot Arid Ecoregion

• The western Plain (Kachchh and part of Kathiawar peninsula), hot and arid agro- ecoregion, covers south western parts of the States of Punjab and Haryana, western parts of Rajasthan, Kachchh peninsula and northern part of Kathiawar peninsula in Gujarat State.
• The area accounts to 31.9 m ha, representing 9.78 per cent of the total geographical area of the country.
• The region is characterized by typical hot summer and cool winter (arid). The mean annual precipitation is less than 400 mm. The ecosystem represents aridic soil moisture and hyperthermic soil temperature regimes with an annual LGP of less than 90 days.
• The sandy soils, represented by Thar series (Torripsamments), are moderately calcareous and alkaline in reaction. The area is under rain fed Mono-cropping (traditional) agriculture. The resistant and short duration rainy season crops, such as pearl millet, chari (fodder), and pulses are grown in non-saline areas.
• In areas favoured by availability of irrigation water, cotton, sugarcane, mustard, gram and wheat are grown.
• The natural vegetation comprises sparse, sporadic tropical thorn forest. Recent statistics show that the forest area in the region is drastically reduced from 15 to almost 1 per cent.
• Constraints:
  • Erratic and scanty rainfall leading to high water deficit.
  • Soil salinity leading to frequent physiological droughts.
  • Nutrient imbalance, especially for N, P Zn and Fe.

3. Deccan Plateau, Hot Arid Eco-Region

• It comprises a part of the Deccan plateau that includes the districts of Bellary, SW parts of Bijapur and Raichur of Karnataka and Anantapur of Andhra Pradesh.
• The region covers an area of 4.9 m ha, representing 1.5 per cent of the total geographical area of the country.
• The climate is characterized by hot and dry summer and mild winter. The rainfall is erratic and ranges from 400 to 500 mm. The region experiences severe drought conditions almost throughout the year.
• The LGP is of less than 90 days.
• The soils are represented by gently sloping shallow and medium red loamy and level to very gently sloping, deep, clayey black soils. The dominant Red (loamy) soils are slightly acidic and non calcareous; the subdominant deep, clayey black soils are slightly alkaline and calcareous in nature.
• The traditional practice is rainfed farming which includes fallowing the land in rainy season and growing of crops in the post-rainy season on residual soil moisture. However, some farmers do grow pearl millet, with limited risk during the rainy season. The common post-rainy season crops are sorghum and safflower.
• Groundnut, sunflower, sugarcane and cotton are intensively grown under irrigated conditions wherever feasible.
• The natural vegetation of the area comprises tropical thorn forest.
• Constraints:
  • High runoff and erosion hazard during stormy cloud bursts.
  • Prolonged dry spells during crop growing period resulting in occasional crop failure.

4. Northern Plain (And Central Highlands) Including Aravallis, Hot Semi-Arid Ecoregion

• It constitutes the parts of Gujarat, northern plains and central highlands covering an area of 32.3 m ha and representing 9.8 per cent of the total geographical area of the country.
• The climate of the region is characterized by hot and dry summer and cool winter. The annual precipitation ranges from 500 to 1000 mm with an increasing trend from west to east.
• The LGP ranges between 90 and 150 days.
• The parts of Bundelkhand region are subjected to occasional and acute drought.
• The soils are moderately to gently sloping, coarse to fine loamy. Almost 65 per cent of the region is under irrigated agriculture. The remaining part is under traditional rainfed agriculture.
• In northern plain, the droughty climate is overcome by introducing tube well irrigation and the area is intensively cultivated for both kharif and Rabi crops, such as rice, millets, maize, pulses, berseem, wheat, mustard and sugarcane.
• The natural vegetation comprises tropical dry deciduous and thorn forests.
• Constraints
  • Coarser soil texture and low plant available water capacity (AWC).
  • Over exploitation of groundwater, resulting in lowering of groundwater table in some areas.
  • At places, imperfect drainage conditions lead to spread of surface and subsurface soil salinity.

5. Central (Malwa) Highlands, Gujarat Plains And Kathiawar Peninsula Ecoregion

• The eco-region covers the Central highlands (Malwa), Gujarat plains and Kathiawar peninsula, western parts of Madhya Pradesh, south-eastern parts of Rajasthan and Gujarat States.
• It covers an area of 17.6 m ha, representing 5.4 per cent of the total geographical area of the country.
• The climate of the region is characterized by hot and wet summer and dry winter. The annual precipitation in the region ranges from 500 to 1000 mm.
• The LGP ranges from 90 to 150 days in a year.
• The dominant soils, representing the region are gently to very gently sloping deep, loamy to clayey and nearly level to very gently sloping deep Black soils.
• Dry land farming is the common practice in the region. The Kharif crops usually cultivated in the area are sorghum, pearl millet, pigeonpea, groundnut, soybean, maize and pulses. The common Rabi crops are sorghum, safflower, sunflower and gram. Wheat is grown under irrigated conditions.
• The natural vegetation comprises dry deciduous forest.
• Constraints:
  • The intermittent dry spell periods.
  • Salinity and alkalinity hazards under irrigated agriculture.
  • Severe salinity and seasonal inundation by sea water in the Kathiawar coast resulting in crop failure.

6. Deccan Plateau, Hot Semi-Arid Eco-Region

• The eco-region with hot, semi-arid climate covers the Deccan plateau, comprising most of the central and western parts of Maharashtra, northern parts of Karnataka and western parts of Andhra Pradesh.
• It spreads over 31.0 m ha, representing 9.5 per cent of the total geographical area of the country.
• The climate is characterized by hot and humid summer and mild and dry winter. The mean annual precipitation, ranges between 600 and 1000 mm.
• The LGP ranges from 90 to 150 days.
• The soils are loamy and clayey soils.
• The traditional practice is rainfed agriculture. The sorghum, pigeonpea and pearlmillet are major kharif season crops. Cotton and groundnut are grown under irrigated conditions.
• The natural vegetation in the region comprises tropical, dry deciduous and thorn forests.
• Constraints
  • Prolonged dry spells adversely affect the crop growth and lead to crop failure in some years.
  • High runoff during stormy cloud bursts in the rainy season result in heavy soil loss.
  • Deficiency of N, P and Zn leads to nutrient imbalance.

7. Deccan Plateau (Telangana) And Eastern Ghats, Hot Semiarid Ecoregion

• The agro eco-region with hot, semi-arid climate and supporting Red and Black soils covers the parts of the Deccan plateau (Telangana) and major parts of Eastern Ghats of Andhra Pradesh.
• It occupies an area of 16.5 m ha, representing 5.2 per cent of the total geographical
• area of the country.
• The climate is characterized by hot and moist summer and mild and dry winter. The mean annual rainfall, ranges from 600 to 1100 mm.
• The LGP ranges from 90 to 150 days.
• The area, covering the districts of Nalgonda, Mahbubnagar, Kurnool, Prakasam, Nellore and Cuddapah, are recognized as drought-prone.
• The Black Cotton soils are clayey, calcareous and strongly alkaline in reaction showing remarkably swell and shrink phenomena on wetting and drying. They have high production potential.
• The Red soils are non-calcareous and neutral in reaction. Rainfed agriculture is the traditional practice.
• The major Kharif crops grown in the area are sorghum, cotton, pigeonpea, rice, groundnut and castor. At places rice is cultivated under irrigation in Rabi season.
• The natural vegetation comprises tropical, dry deciduous and thorn forests.
• Constraints
  • High runoff during rainy season leads to severe soil and nutrient loss both in the Red and Black Soil areas.
  • Under irrigated agriculture, injudicious use of irrigation water and imperfect drainage conditions result in high groundwater table leading to subsoil salinity and sodicity, especially in the Black soil areas.
  • Deficiency of N, P and Zn in soils results in nutrient imbalance.
  • Frequent drought results in crop failure in some years.

8. Eastern Ghats And Tamil Nadu Uplands And Deccan (Karnataka) Plateau, Hot Semiarid Eco- Region

• The agro eco-region with hot, semi-arid climate and Red loamy soils covers EasternGhats, southern parts of Deccan plateau, Tamil Nadu uplands, and western parts of Karnataka.
• It has an area of 19.1 m ha, representing 5.8 per cent of the total geographical area of the country.
• The climate of the region is characterized by hot and dry summer and mild winter. It receives an annual rainfall of 600 to 1000 mm. The western parts of the region falling in Karnataka receive about 70 per cent of the rainfall during June to September. The eastern parts receive rains during October to December.
• The LGP ranges from 90 to 150 days.
• The rainfed agriculture is the traditional practice in the region. The millets, pulses, and groundnut are cultivated in kharif season, while sorghum and safflower are grown in Rabi season. Rice is cultivated under irrigation. At places sugarcane and cotton are also grown under irrigated conditions.
• The natural vegetation comprises tropical, dry deciduous and thorn forests.
• Constraints
  • High runoff that results in severe soil erosion.
  • Nutrient imbalance, resulting from deficiency of N, P and Zn.

9. Northern Plain, Hot Subhumid (Dry) Eco-Region

• The agro eco-region with hot, sub-humid (dry) climate and alluvium-derived soils covers a part of the northern Indo-Gangetic Plain, including piedmont Plain of the western Himalayas.
• It occupies an area of 12.1 m ha, representing 3.7 per cent of the total geographical area of the country.
• The agro- climate of the region is characterized by hot summer and cool winter. It receives an annual rainfall of 1000 to 1200 mm; 70 per cent of which is received during July to September.
• The region has LGP of 150 to 180 days.
• The soils of the region are generally deep and loamy. They have developed on alluvium. Traditionally the rainfed and irrigated agriculture is common. The crops grown are rice, maize, barley, pigeonpea and jute in kharif season, and wheat, mustard and lentil in Rabi season. Sugarcane and cotton are grown at places under irrigated conditions.
• The natural vegetation comprises tropical dry deciduous forests.
• Constraint:
  • An injudicious use of irrigation water may lead to water-logging and salinity hazards.

10. Central Highlands (Malwa And Bundelkhand), Hot Subhumid (Dry) Ecoregion

• The agro eco-region with hot, sub humid climate and Red and Black soils covers part of Malwa plateau and Bundelkhand uplands including Baghelkhand plateau, Narmada valley, Vindhyan scarplands and northern fringe of Maharashtra plateau, encompassing some districts of Madhya Pradesh.
• It covers an area of 22.3 m ha representing 5.8 per cent of the total geographic area of the country.
• The climate of the region is characterized by hot summer and mild winter. The precipitation shows an increasing trend towards east. The mean annual rainfall ranges between 1000 and 1500 mm. The LGP ranges from 150-180 days.
• Rainfed agriculture is the common practice. Rice, sorghum, pigeonpea and soybean are common grown kharif crops. Gram, wheat and vegetables are common Rabi season crops. Kharif cropping is totally rainfed, whereas Rabi cropping is partly irrigated at critical stages growth.
• The natural vegetation comprises tropical moist deciduous forest.
• Constraints
  • Risk of inundation of the cropped areas during rainy season and risk of acute drought due to prolonged dry spells in Kharif season lading to crop failure at places.
  • Soil loss due to heavy runoff during rainy season resulting in stagnation of water and poor germination.
  • Deficiency of N, P and Zn resulting in nutrient imbalances.

11. Chattisgarh/Mahanadi Basin Agro-Eco-Region

• The agro eco-region, with hot, sub humid climate and supporting red and yellow soils, comprised of eastern plateau. It covers Chhattisgarh region and southwest highlands of Bihar State. It occupies an area of 14.1 m ha, representing 4.3 per cent of the total geographical area of the country.
• The climate of the area is characterized by hot summers and cool winters. The annual rainfall is 1200 to 1600 mm; of which 70-80 per cent is received between July to September.
• The LGP ranges between 150 and 180 days in a year.
• Rainfed agriculture is the traditional farming with cultivation of rice, millets, pigeonpea, moong (green peas) and blackgram (urid) in kharif season. At places wheat and rice are cultivated under irrigated conditions during Rabi season.
• The natural vegetation comprises tropical moist deciduous forest.
• Constraints
  • The soils are susceptible to severe water erosion hazard.
  • Partial water logging in early stages of crop growth and seasonal drought during advance stage crop growth.
  • Deficiency in N, P and micronutrients, such as Zn and B, causes nutrient imbalances.

12. Eastern Plateau (Chhotanagpur) And Eastern Ghats, Hot Subhumid Ecoregion

• The agro eco-region constitutes Chhotanagpur Plateau of Bihar, western parts of West Bengal, Eastern Ghats (Dandakaranya and Garhjat hills) of Orissa and Bastar Region of Chhattisgarh.
• It occupies an area of 26.8 m ha, representing 8.2 per cent of the total geographical area of the country.
• The climate of the region is characterized by hot summers and cool winters. The area receives an annual rainfall of 1000-1600 mm.
• The LGP varies from 150 to 180 days and at places it is 180 to 210 days.
• Soils are fine loamy to clayey, non-calcareous, slightly to moderately acidic and have relatively low cation exchange capacity. The soils are generally shallow on the ridges and plateaus and are under forest cover. The soils in valleys are deep and are generally cultivated.
• Rainfed farming is the traditional practice with cultivation of rice, pulses (moong, blackgram and pigeonpea) and groundnut. In Rabi season, rice (at places) and wheat are cultivated mostly under irrigated condition.
• The natural vegetation comprises tropical dry and moist deciduous forests.
• Constraints
  • The soils are susceptible to severe erosion hazard.
  • Seasonal drought limits optimum crop yields.
  • Deficiency of N, P and some micronutrients, such as Zn and B causes nutrient imbalances.
  • Eastern Plain, hot sub-humid (moist) eco-region

13. Eastern Plain, Hot Subhumid (Moist) Ecoregion

• The agro eco-region, comprising eastern plains covers north-eastern Uttar Pradesh and Northern Bihar including foothills of Central Himalayas. It occupies an area of 11.1 m ha, representing 3.4 per cent of the total geographical area of the country.
• The climate of the region is characterized by hot, wet summer and cool, and dry winter. The area receives an annual rainfall of 1400-1800 mm.
• The LGP ranges from 180 to 210 days in a year.
• The soils in the area are represented by level to very gently sloping alluvium-derived soils. Rainfed agriculture with cultivation of rice, maize, pigeonpea, moong are common in kharif season. In post-rainy (Rabi) season, wheat, lentil, pea, sesamum, and at places, groundnut is grown on residual soil moisture with one or two protective irrigations at critical stages.
• The important cash crops such as sugarcane, tobacco, chillies, turmeric, coriander and potato are usually grown with supplemental irrigation.
• The natural vegetation comprises tropical moist deciduous and dry deciduous forests.
• Constraints
  • Flooding and imperfect drainage conditions limit soil aeration.
  • Salinity and/or sodicity, occurring in patches, affect crop yields.
  • Deficiency of N, P and Zn results in nutrient imbalances.

14. Western Himalayas, Warm Subhumid (To Humid With Inclusion Of Perhumid) Ecoregion

• The agro eco-region comprising western Himalayas covers Jammu and Kashmir, Himachal Pradesh and north-western hilly areas of Uttar Pradesh. It occupies an area of 21.2 m ha, representing 6.3 per cent of the total geographical area of the country.
• The region represents warm sub-humid to cool humid (with inclusion of perhumid) ecosystem and is characterized by mild summer and cold winter.
• The rainfall in general varies from 1000-2000 mm. It is more than 2000 mm in parts of Himachal and Uttar Pradesh comprising Humid and Per-humid pockets in the region.
• The major soils occurring in the region are shallow to deep, medium having high organic matter content, and weak to well-developed horizons. They are classified as Brown Forest and Podzolic Soils.
• Rainfed farming is the traditional practice in the valleys and on terraces. The common crops grown are wheat, millet, maize and rice. The terraced uplands are cultivated for paddy and/or horticultural plantation crops, like apples.
• The natural vegetation comprises Himalayan moist temperature, subtropical pine and sub-alpine forests.
• Constraints
  • Severe climate, especially cryic/frigid temperature regime, in northern high altitude permits limited choice of crops.
  • Deforestation and excessive slopes favour soil erosion.
  • Soil degradation, results in common landslides. .
  • Soil acidity, especially in Kangra and Manali areas of Himachal Pradesh

15. Assam And Bengal Plain, Hot Subhumid To Humid (Inclusion of Perhumid) Eco-Region

• The agro eco-region, comprising the plains of the Bramhaputra and the Ganga Rivers, covers parts of the States of Assam and West Bengal.
• The region occupies an area of 12.1 m ha, representing 3.7 per cent of the total geographical area of the country.
• The climate of the area is characterized by hot summer and mild to moderately cool winter. The intensity of precipitation increases in northern and eastern parts of (Bengal basin and Teesta Bramhaputra Plain) as compared with the southern parts (Ganga Plain).
• The rainfall in Ganga Plain ranges between 1400 and 1600 mm; and in Barak Basin (Tripura Plain) and Teesta-Brahmaputra Plains from 1800 to 2000 mm.
• The LGP, in general, is more than 210 days in a year.
• In view of the high rainfall, the rice based cropping system is common in the Brahmaputra, Teesta and Ganga Plains. The rice and jute are main crops grown in rainy season under rainfed condition.
• In northern foothills of eastern Himalayas, encompassing Teesta and Bramhaputra regions, plantation crops, such as tea and horticultural crops like pineapple, citrus and banana are grown.
• The natural vegetation comprises tropical moist and dry deciduous forests.
• Constraints
  • Flooding and water logging
  • Excessive leaching of bases and nutrients, resulting in low base status soils, especially in the Bramhaputra (Assam) Plain.

16. Eastern Himalayas, Warm Perhumid Eco-Region

• The eastern Himalayan agro eco-region encompasses northern hilly parts of West Bengal, northern parts of Assam, Arunachal Pradesh and Sikkim States.
• It occupies an area of 9.6 m ha, representing 2.9 per cent of the total geographical area of the country.
• The climate of the region is characterized by warm summer and cool winter. The annual rainfall is 2000 mm. The area experiences short period of water stress during post-rainy period because of seasonal water deficit.
• The water balance shows the longest LGP (more than 270 days) in a year.
• The dominant soils in the region vary from shallow to moderately shallow, loamy, Brown Forest to deep, organic matter rich soils with moderate to low base status.
• In general, Jhum cultivation is the traditional farming. It is practiced with mixed cropping on the steep slopes under rainfed condition at an interval of 3-4 years. Another type of traditional practice is the cultivation of millets on upland terraces and potato, maize, millets and paddy in valleys. In the hilly areas, vegetables and plantation crops like tea, and medicinal plants, and horticultural crops like pineapple, citrus, apple, peer, peach, banana are grown on terraces.
• The natural vegetation comprises subtropical pine forest and temperate wet evergreen forests, subalpine forest, etc.
• Constraints
  • Steeply sloping landforms encourage heavy runoff resulting in severe erosion hazards.
  • Deforestation for shifting cultivation leads to severe soil degradation problem.
  • High rainfall leading to intense leaching results in soils with poor base status.
  • Excessive moisture leading to water stagnation in valleys during (post) monsoon period limits the choice of crop.
  • Low temperature during post-monsoon period limits the cultivation of second arable crops. Monocropping is therefore commonly practiced in these regions.

17. North-Eastern Hills (Purvanchal), Warm Perhumid Ecoregion

• The north-eastern hills (Purvanchal) agro eco-region comprises hilly States of Nagaland, Meghalaya, Manipur, Mizoram and southern Tripura. The region covers an area of 10.6 m ha, representing 3.3 per cent of the total geographical area of the country.
• The agro-climate of the region is characterized by warm summer and cool winter. The annual precipitation varies from 2000 to 3000 mm.
• LGP exceeds 270 days in a year.
• The major soil formations in the area include shallow to very deep, loamy, Red and Lateritic and red and yellow soils.
• Jhum cultivation is the traditional farming. Rice is the dominant crop grown in valleys and on hill terraces. Millets, maize and potatoes are cultivated on terraces at higher altitudes, while rice and jute are grown in small under rainfed condition. Hill terraces are also used for plantation crops, such as, tea, coffee, rubber and horticultural crops, like oranges, pineapple, etc.
• The natural vegetation comprises wet evergreen and tropical moist deciduous forests.
• Constraints
  • Deforestation and shifting cultivation result in severe soil erosion hazard.
  • Excessive rainfall leading to leaching results in depletion of nutrients rendering soils poor in base status.
  • Small to marginal land holdings limit the introduction of modern implements.

18. Eastern Coastal Plain, Hot Subhumid To Semiarid Ecoregion

• The agro eco-region comprises the south-eastern coastal plain, extending from Kanyakumari to Gangetic Delta.
• The region covers an area of 8.5 m ha, representing 2.6 per cent of the total geographical area of the country.
• The Eastern Coast extending from Kanyakumari to Gangetic delta experiences wide range of climate conditions. The coastal parts between Kanyakumari and south of Thanjavur (Tamil Nadu) and between north of Madras and west Godavari (Andhra Pradesh) receive the rainfall of 900 to 1100 mm, of which about 80 per cent in October to December.
• The LGP ranges from 90 to 150 days.
• This area represents semiarid climatic conditions.
• The remaining part of eastern coast, that lies between Nagapattinam and Madras (Tamil Nadu) and extending to north-western part of coastal strip, including parts of north-western Godavari (Andhra Pradesh), Orissa and West Bengal, receives 1200 to 1600 mm of rainfall of which 80 percent is received as during June to Sept.
• The LGP is much higher than the southern parts and varies from 150 to 210 days or more in a year. The area represents a sub-humid (moist) climatic type. Hence, the bioclimatic variations in the ecosystem extend from semi-arid to sub-humid, and the length of growing period ranges from 90 to 210 days.
• The region has been grouped in one agro-ecosystem because of maritime climatic influences and limited area.
• Both rainfed and irrigated agriculture are practiced in the region. The lead crop cultivated in the area, both in kharif and Rabi season, is rice. Coconut is a dominant plantation crop of the region. In some parts, pulses, such as blackgram and lentil, and oilseed crops, such as sunflower and groundnut are cultivated after rice.
• Besides agriculture, raising of coastal and brackish water fisheries are important economic activities of the coastal people.
• Constraints
  • Soil salinity (and sodicity at places) resulting from poor drainage conditions adversely affect crop production.
  • The area is prone to cyclone during monsoon and retreating monsoon periods.

19. Western Ghats And Coastal Plain, Hot Humid-Perhumid Eco-Region

• The agro eco-region comprises Sahyadris, western coastal plains of Maharashtra, Karnataka and Kerala States, including Nilgiri hills of Tamil Nadu.
• The region occupies an area of 11.1 m ha, representing 3.6 per cent of the total geographical area of the country.
• The climate is characterized by hot and humid summer and warm winter. The mean annual temperature varies between 25°C and 28°C. The mean annual rainfall exceeds 2000 mm in most of the areas.
• The region is represented by a longer LGP ranging between 150 and 210 days. At places it exceeds 210 days in a year.
• The major soils of the region include Red and Lateritic Soils along the leeward flank of Sahyadris and the alluvium-derived soils in the coastal plains.
• The area is intensively cultivated for rice, tapioca, coconut and spices.
• The natural vegetation comprises tropical moist deciduous forests.
• Constraints
  • Excessive leaching that leads to depletion of plant nutrients and bases.
  • Water logging, resulting from imperfect drainage conditions affects crop growth in the coastal plains.
  • Steep slopes, causing runoff, leads to severe soil erosion.
  • Inundation of land area results in localized saline marshes.

20. Islands Of Andaman-Nicobar And Lakshadweep, Hot Humid To Perhumid Island Ecoregion

• The agro eco-region comprises the group of islands of Andaman and Nicobar in the east and that of Lakshadweep in the west.
• The region covers an area of 0.8 m ha, representing 0.3 per cent of the total geographical area of the country.
• The climate is typified by tropical conditions with little difference between mean summer and mean winter temperatures.
• The annual rainfall of these two far- seated areas varies from 1600 to 3000 mm. The Lakshadweep Islands receives 1600 mm rainfall representing humid climate, and the Andaman-Nicobar group of Islands receiving 3000 mm rainfall representing per-humid climate.
• The LGP is more than 210 days which is long enough to support double cropping system and plantation crops grown in the area.
• The soils of the Andaman and Nicobar Islands (in the East) greatly differ from those of Lakshadweep Islands (in the West). The former shows medium to very deep, Red loamy soils including marine alluvium derived soils along the coast. The soils of Lakshadweep Group of Islands, on the other hand, are highly calcareous and sandy in nature.
• The natural vegetation comprises tropical rain (evergreen) and littoral and swamp forests. About 2/3 of the Andaman is under native forest and agriculture is confined only to specific areas around habitations, where the dominant crop grown is rice.
• In general, the land use is dominated by plantation crops, such as coconut, arecanut, oil palm with or without inter-cultivation of pineapple, tapioca and pepper.
• In Lakshadweep, rice is mainly grown under lowland conditions. Coconut is the main plantation crop with high yield. Besides agriculture, marine fishery is an important means of subsistence for the people.
• Constraints
  • Degradation of the tropical rain-forest ecosystem leads to severe soil erosion hazard. With the clearing of rain forests, the ecosystem is disturbed resulting in severe soil erosion.
  • Inundation of coastal areas leads to saline marshes and consequently formation of acid sulphate soils.
  • Gradual increase in areas under mangroves suggests increase in degradation of the coastal areas.