MAJOR SOIL GROUPS (Part-2)

Red soils (Acrisols)

Ancient crystalline and metamorphic rocks have given rise to red soils. These soils are found predominantly in the states of Andhra Pradesh, Tamil Nadu, Karnataka, Maharashtra, Orissa, Goa and in the northeastern states. They have limitations of soil depth, poor water and nutrient-holding capacity, excessive drainage, runoff and are generally poor in N, P, zinc (Zn), sulphur (S) and humus. Under good management, these soils can be used profitably for a variety of crops such as millets, rice, groundnut, maize, soybean, pigeon pea, green gram, jute, tea, cashew, cocoa, grapes, banana, papaya and mango.

Laterite and lateritic soils (Ferralsols and Dystric Nitisols)

Laterite and lateritic soils are deeply weathered soils with a high clay content, having low base and silica owing to pronounced leaching. They are generally found in Kerala, Tamil Nadu, Karnataka, Andhra Pradesh and the northeastern region, and occupy about 25 million ha. The major limitations posed by these soils include deficiency of P, potassium (K), calcium (Ca), Zn and boron (B), high acidity and toxicity of aluminum (Al) and manganese (Ma). The important crops grown on these soils are rice, banana, coconut, areca nut, cocoa, cashew, coffee, tea and rubber.

Desert (arid) soils (Arenosols, Calcisols and Gypsisols)

Desert soils constitute the soils with negligible vegetation in both hot and cold regimes. They cover an area of about 29 million ha. The sandy material results in poor profile development under arid conditions. Water deficiency is the major constraint in cultivating these soils. A gypsic horizon is common in extremely arid areas such as Bikaner and Jaisalmer in Rajasthan. These soils are very prone to wind erosion.

Forest and hill soils (Cambisols and Luvisols)

Forest and hill soils are found at high as well as low elevations where rainfall is sufficiently high to support forest growth. Soil formation is governed mainly by the deposition of organic matter derived from the forest growth. Brown forest and Podzolic soils are common in the Northern Himalayas, while the Deccan Plateau forests have red and lateritic soils.

Saline and sodic soils (Solonchaks and Solonetz)

Saline and sodic soils occur under semi-arid conditions and occupy an area of 10 million ha. They are widely distributed in Rajasthan, Punjab, Haryana, Uttar Pradesh, Madhya Pradesh, Maharashtra and Gujarat. The sodic soils pose serious problems of a high sodium (Na) content, poor physical conditions and nutrient deficiency. Despite many limitations, once ameliorated using gypsum, sodic soils are used successfully for growing rice followed by wheat.

Peaty and marshy soils (Histosols)

Peaty and marshy soils are formed by plants growing in the humid regions under permanently waterlogged conditions. They are found in Kerala, Orissa, West Bengal (Sundarbans) and along the South-East coast of Tamil Nadu. Where properly drained and fertilized, these soils often produce a very good rice crop.

Visit Website

MAJOR SOIL GROUPS (Part-1)

The great diversity in landforms, geological formations and climate conditions in India has resulted in a large variety of soils. Apart from a few soil orders (Andisols and Spodosols), all the major soils of the world are represented in India. Broadly, Indian soils consist of eight major groups, of which four are of agricultural importance: alluvial soils, black soils, red soils and lateritic soils. The four other broad soil groups that occur fairly extensively in India are: saline and sodic soils, desert soils, forest and hill soils, and peaty and marshy soils. These soil groups are related closely to the geographical character and the climate of the regions in which they occur.

Alluvial soils (Fluvisols)

Alluvial soils constitute the largest and most important soil group of India and contribute most to the agricultural wealth of the country. The soils are derived from the deposition of silt by the numerous river systems. They cover about 75 million ha in the Indo-Gangetic Plains (IGP) and Brahmaputra Valley and are distributed in the states of Punjab, Haryana, Uttaranchal, Uttar Pradesh, Bihar, West Bengal, Assam and the coastal regions of India. These soils are deficient in nitrogen (N), phosphorus and organic matter. Generally, alluvial soils range from near neutral to slightly alkaline in reaction. A wide variety of crops is grown in these soils.

Black soils (Vertisols)

Black soils are very dark and have a very high clay content. They have a high moisture retention capacity. They become extremely hard on drying and sticky on wetting. Hence, they are very difficult to cultivate and manage. These soils cover an area of about 74 million ha, mainly in the central, western and southern states of India. They are inherently very fertile. Under rainfed conditions, they are used for growing cotton, millets, soybean, sorghum, pigeon pea, etc. Under irrigated conditions, they can be used for a variety of other crops, such as sugar cane, wheat, tobacco and citrus crops.

Visit Website

AGRO-ECOLOGICAL ZONES

Agriculture is highly dependent on soils and climate. The ever-increasing need for food to support the growing population in the country demands a systematic appraisal of its soil and climate resources in order to prepare effective land-use plans. India has a variety of landscapes and climate conditions and this is reflected in the development of different soils and types of vegetation. Based on 50 years of climate data and an up-to-date soil database, the country has been divided into 20 agro-ecological zones (AEZs), Each AEZ is as uniform as possible in terms of physiography, climate, length of growing period and soil type for macrolevel land-use planning and effective transfer of technology.
Visit Website

Agriculture In India An Introduction

India is a country of more than 1 000 million people. It is the seventh largest nation in the world with a geographical area of 328.7 million ha. Agriculture is the mainstay of the Indian economy, contributing about 22 percent of gross domestic product (GDP) and providing a livelihood to two-thirds of the population. The net cultivated area has been about 141 million ha for the last 30 years. However, there has been a progressive increase in the gross cropped area as the cropping intensity has increased from 118 to 135 percent in the last three decades. The total gross cropped area is about 190 million ha. There are 115.6 million farmholdings, with an average size of 1.41/ha.

The country has a diverse landscape and a climate varying from the areas with highest rainfall such as Mawsynram near Cherrapunji (Meghalaya) to the driest parts of western Rajasthan with negligible rain and from a hot and humid southern peninsula to the snowbound Himalayan Mountains. Broadly, the climate of India is of the tropical monsoon type. It has four seasons: winter (January–February), a hot summer (March–May), rainy southwest monsoon (June–September), and post-monsoon (October–December). The climate is affected by two seasonal winds: the southwest monsoon and the northeast monsoon. The distribution of rainfall is very uneven in terms of time and space. About 72 percent of the area receives an annual rainfall of no more than 1 150 mm.

India has a net irrigated area (land area that receives irrigation from the different sources) of 54.68 million ha and a gross irrigated area (total area of crops that are irrigated) of 75.14 million ha (the largest in the world). Surface water and groundwater resources contribute 46 and 54 percent, respectively, of the total. Food crops occupy 69 percent of the irrigated area, the remaining 31 percent being under non-food crops.

visit website