After reading this article you will learn about the soils found in various agro-ecological regions of India.
Humid to Semi-Arid Western Ghats and Plateau of Karnataka:
The Western Ghats and highlands to Tamil Nadu are humid but rest of the area is semi-arid. The average annual rainfall in the central Western Ghat ranges from 600 to 2,000 mm and in the southern part from 2,000 to 3,000 mm. The region consists of Karnataka, Tamil Nadu, Kerala, Pondicherry and Lakshadweep Islands.
The regions can be divided into Western Ghats, plateau, river valleys, undulating rock plains and coastal plains. The predominant soil groups are black, red, lateritic and alluvial. Black soils are found in the northern part of the Karnataka plateau whereas red soils are in southern part. In the Western Ghats, acidic lateritic soils are predominant.
Semi-Arid Lava Plateau and Central Highlands:
The region consists of Maharashtra, western and central Madhya Pradesh, Goa, Daman and Diu. The region is predominantly plateau. The climate is semi-arid with extremes of temperatures and variable rainfall. The annual rainfall varies from 700 to 1250 mm but in the Western Ghats it varies from 3340 to 7450 mm. The important soil groups of the region are alluvial black and lateritic.
Arid Western Plains:
The region consists of Haryana, Rajasthan, Gujarat, Dadra and Nagar Haveli. It is extensively sandy alluvial plains. The annual rainfall varies from 100 mm to 650 mm. The major soil groups are alluvial, grey-brown alluvial, black, desert, saline and sodic.
Sub-Humid to Humid Eastern and South-Eastern Uplands:
This region consists of Andhra Pradesh and eastern Madhya Pradesh and Orissa. The average annual rainfall varies from 1000 to 1800 mm. The region is characterised by undulating topography, denuded hills, plateau, mature river valleys, highlands of Eastern Ghats and wide basins of Chhattisgarh, Tel, Ugali and Shohagpur. The important soil groups are red, black, yellow, red sandy, laterite, revine alluvial and coastal sandy alluvial.
Sub-Humid Sutlej-Ganga Alluvial Plains:
The region consists of the Punjab, plains of Uttar Pradesh, Delhi territory and Bihar. The climate is characterised by hot summer and cold winter. The annual precipitation is 300 to 2000 mm. The major soil groups are calcareous, reddish-brown chestnut, new and old alluvium and patches of saline and alkaline soils.
The soil texture varies from fine to coarse. The soils of south Bihar (Chotanagpur regions) are red soils of coarse texture and shallow depth. The laterite soils are present on Rajmahal hills and high level table land.
The soils of north Bihar are calcareous. Alluvium soils are occurring in the Gangetic plain. These soils are very fertile amongst all the soils of India. The soils are deficient in nitrogen, phosphorus and humus but not generally in potash and lime. They produce a wide variety of crops including rice, wheat, sugarcane, jute and potato.
Humid Eastern Himalayan Region and Bay Island:
This region represents the States of Meghalaya, Manipur, Tripura, Nagaland and the Union Territories of Arunachal Pradesh, Mizoram and Andaman and Nicobar Islands. The major soil groups are brown hill red and yellow alluvial and laterite. In the foothills, the alluvial soils are loam to sandy loam in texture and slightly acidic to neutral in reaction. The average annual rainfall varies from 2000 to 4000 mm.
Humid Bengal-Assam Basin:
This region represents the Ganga-Brahmaputra alluvial plain. The tarai (sub-montane) is found in Jalpaiguri and Darjeeling districts of Bengal. The Medinipur coast comprises semi-stabilized sand dunes, formed on alluvial terraces. The laterite remnants are found in Gondwana. The Assam valley is an aggradation plain of the Brahmaputra and its tributaries.
The dominant soil groups are alluvial, red, brown hill and coastal. Saline and alkaline soils are present in extensive patches in deltaic tracts. The pH ranges from 4.8 (laterite soils) to 8.2 (alluvium soils). The average rainfall varies from 2200 to 4000 mm.
Humid Western Himalayan Region:
This region comprises of Jammu and Kashmir, Himachal Pradesh and the hill divisions of Kumaon and Garhwal of Uttar Pradesh. The annual average rainfall ranges from 80 mm in Ladakh to 1150 cm in Jammu and 500 to 3500 mm in the hills of Himachal Pradesh and Uttar Pradesh.
The predominant soil groups are mountain meadow, sub-mountain meadow and brown hill soils. The mountain meadow soils are neutral to alkaline in reaction and sandy loam in texture. The sub-mountain soils are acidic loam and sandy loam. The brown hill soils are loam to silty loam in texture. The moist fine-textured soils are found in the valley of Kashmir whereas coarse-textured dry soils in the plateaus.