Different Types of Soil in India and their Characteristics

Table of Contents

• Introduction to Soil
• What is the Process of Soil Formation?
  • Weathering
  • Accumulation of Organic Matter
  • Translocation
• What are the Five Major Factors Affecting Soil Formation?
• What are the Different Types of Soil in India?
• Soil Types and Its Impact on Farming in India

Introduction to Soil

Soil is the most critical factor affecting the crops we grow for our consumption. It is a valuable natural resource that forms the upper layer of the earth's mantle. The soil in its present form is the result of thousands of years of weathering and gradation of parent rock material.

Soil is a thin, loose layer of different materials like rock, minerals, and organic matter, which forms over the earth's surface to support the growth of plants. Thus, the major components of soils are:

• Organic matter – decomposed plants and animals.
• Inorganic matter – minerals and rock debris derived from parent rocks.
• Water
• Air

Different types of soil contain these materials in different amounts. Some soils are abundant in one or more of these, while others may be deficient in one or more. Ideally, soil should have 50% solid material and 50% pore space. Even the pore spaces should consist of half air and half water.

What is the Process of Soil Formation?

The process of soil formation is also known as pedogenesis. The soil formation process is a series of interrelated physical, chemical, biological and climatic activities that transform parent rock material into finer soil particles that we see today.

The soil forms through three important processes – weathering, accumulation of organic matter, and translocation.

Weathering

The first step of soil formation is weathering. It is the process of breaking down parent rock materials through physical and chemical processes into smaller particles.

Physical weathering is the mechanical breakdown of parent rock materials into smaller materials due to changes in temperatures, pressures, and wind.

Chemical weathering is the decomposition of rocks through chemical reactions. It happens when minerals within rocks change their chemical composition due to gases in the atmosphere and water.

Accumulation of Organic Matter

Organic matter consists of dead plants and animals, which, upon decomposition, form humus. This process is also known as humification.

Translocation

It involves the movement of soil constituents like minerals and organic matter within the soil profile (vertical classification of soil) or between the horizons. Translocation of soil happens through the process of leaching and illuviation.

What are the Five Major Factors Affecting Soil Formation?

Five major factors affect soil formation: physical relief, parent rock material, climate, biological activity, and time. Let's briefly examine how these factors influence soil formation.

• Physical Relief (Topography): The shape and direction of land affect soil formation. Flat land surfaces, like Indo-Gangetic plains, have deeper fertile soils, whereas slopes have fewer deeper soils.
• Parent Rock Material: The weathering of the parent material is the main source of soil formation. Thus, the nature of the parent rock determines the colour, composition, and fertility of the soil. For instance, black soil is the result of the weathering of lava rocks of the Deccan Plateaus.
• Climate: Rain and temperature determine the pace with which the parent rock will break, the extent of soil development, and the composition of the soil.
• Time: Soil formation is a dynamic and long-term process. The time determines the maturity and profile development of the soil.
• Biological Activity: Organic matter, such as decomposed plants and animals, helps determine the soil's structure and composition. 

Besides, human activities also influence the formation of soils.

What are the Different Types of Soil in India?

India has diverse landforms, climatic conditions, and vegetation. As a result, different types of soils are found in India. In ancient India, two types of soil were mentioned – Urvara (fertile) and Usara (infertile/sterile).

Adopting the scientific approach for soil classification after Independence, the Indian Council of Agricultural Research (ICAR) has given 8 major soil classifications based on genesis, colour, composition, and location. We have given the soil type chart of the major soils of India below.

Soil Types and its Impact on Farming in India

Soil plays a critical role in increasing agricultural productivity. That is why knowledge of soil type, texture, composition, fertility, etc., is essential. Soil type is a significant contributing factor in the high agricultural productivity of the top agri-producing states of India.

Alluvium soil, black soil, and red soil, which collectively account for over 75% of India's land, are primarily found in specific regions. These regions include the Indo-Gangetic plains, the Deccan plateaus, and the East Coast. Interestingly, these are also the geographic areas where India's most agriculture producing states are located.

Further, other soil types, such as arid soil, saline soil, peaty soil, forest soil, and laterite soil, are also found in these states. This additionally supports agriculture in the top agri-producing states of India.