1.jpeg

## Soil Resources ### Syllabus - Types of soils (alluvial, black, red and laterite), distribution, composition and characteristics such as colour, texture, minerals and crops associated. - Soil Erosion - causes, prevention and conservation. ### Soil Soil is the thin layer of loose mixture of sma...

## Soil Resources ### Syllabus - Types of soils (alluvial, black, red and laterite), distribution, composition and characteristics such as colour, texture, minerals and crops associated. - Soil Erosion - causes, prevention and conservation. ### Soil Soil is the thin layer of loose mixture of small rock particles and rotting organic matter that covers the surface of the earth. It supports forests, grasslands and crops from which all living creatures on earth derive their energy. Various forces of nature such as changing temperature, running water and wind affect formation of soil. These forces of nature along with the chemical and organic changes that take place in the soil contribute to the evolution of soil. Thus soil itself, has evolved over millions of years. Faulty agricultural practices, overgrazing and deforestation lead to soil erosion. Improved agricultural practices, reduced pressure of grazing and afforestation can help in the conservation of soils. ### Constituents of Soil Soils are derived from parent rock material through a process of breakdown or wear and tear. Decomposed vegetal and animal remains, called humus, is an important constituent of soil and adds to the fertility of the soil. Besides humus, silica, clay and sand are the other constituents of soil. ### Soil Fertility Soil fertility refers to the strength of the soil to support plant life. Fertile soil has the following characteristics: - **It contains adequate amount of moisture to supply essential nutrients to the plants** - **It has sufficient depth to enable the plants to grow their roots as per their requirement** - **It is rich in nutrients such as nitrogen, phosphorus and potassium, that are necessary for basic plant nourishment.** - **It contains organic matter that improves the structure of soil.** Soil fertility can be improved by adding missing nutrients in the form of fertilizers to the soil. ### Soil Classification According to its location, soil can be categorized as: 1. **Residual or Sedimentary Soil:** Almost all soils are formed 'in situ', that is, they are formed in their original position by the breaking down of parent rocks. They have a well defined soil profile. They include black soil, red soil, laterite soil, desert soil, etc. 2. **Transported Soil:** These soils are 'ex situ', that is, transported by various agents of erosion and consist of sediments carried and deposited by rivers and winds. Hence they do not have a well defined soil profile. Alluvial soils are transported soils. ### Types of Soil India is a vast region with varied natural environment. We find several physiographic regions and different types of climate. Therefore, a number of soil types have developed here. On the basis of their origin, colour, composition and location, the soil of India have been classified into the following types.