Soil Science

Laterite soils are formed under conditions of high temperature and heavy rainfall with alternate dry and wet periods, leading to intense leaching. This process leaves behind a soil rich in iron oxide and aluminum, which is highly acidic and infertile for general agriculture.

Alluvial soil is the most widely spread and important soil. In fact, the entire northern plains are made of alluvial soil. Alluvial soils as a whole are very fertile. Due to its high fertility, regions of alluvial soils are intensively cultivated and densely populated. 

Khadar is the term used for new, fertile alluvial soil that is deposited annually by river floods. Consequently, Khadar soils are primarily found in active flood plains.

The Indo-Gangetic plain is composed of alluvial soil. This soil is formed from sediments carried down and deposited by major rivers originating in the Himalayas, meaning it is derived from Himalayan rocks.

The correct order of soil particles by increasing grain size is Clay (less than 0.002 mm), Silt (0.002 to 0.05 mm), Sand (0.05 to 2.0 mm), and Gravel (greater than 2.0 mm). This corresponds to the sequence 1, 2, 3, 4 (or A, B, C, D).

Black soil, also known as regur, has high clay content and excellent moisture retention, making it exceptionally well-suited for growing cotton.

Tea plants require deep, well-drained, acidic soils with high organic matter. Laterite soils, which are acidic and found on well-drained hill slopes, are highly suitable for tea plantations when properly fertilized.

Black soil is highly clayey and retains moisture for a long time, which is ideal for the deep-root system of the cotton plant. It is widely cultivated in the Deccan plateau region for this cash crop.

Clayey soil consists of very fine particles with minimal space between them. This tight packing prevents water from draining quickly, allowing it to retain the maximum amount of water compared to other soil types.

Red soil develops on crystalline igneous rocks in areas of low rainfall in the eastern and southern parts of the Deccan plateau. These soils develop a reddish colour due to diffusion of iron in crystalline and metamorphic rocks.  

Lateritic soil types of India are rendered infertile by the presence of excess iron. Laterite soils are those soils that are found in the areas which receive high rainfall and have a very high temperature. This results in less humus content in the soil. Hence, they are not fertile soil and are not suitable for cultivation.

Laterite soils are good for tea, coffee and cashew cultivation. Laterite soils lack fertility due to intensive leaching. When manured and irrigated, some laterites are suitable for growing plantation crops like tea, coffee, rubber, cinchona, coconut, areca nut, etc.

It is red due to the presence of iron oxide which is formed by leaching. Laterite soil is a rock type soil rich in iron and aluminium, and is commonly considered to have formed in hot and wet tropical areas.

Black soil, also known as regur soil, is highly clayey and retains moisture well, making it excellent for crops like cotton and wheat. However, it is not suitable for groundnuts, which require well-drained, loose sandy loam soils to allow the underground pods to develop and to facilitate easy harvesting.

The Deccan Plateau is famous for its fertile black soil, which is formed from weathered volcanic basalt. This soil is rich in iron and other minerals, retains moisture exceptionally well, and is ideal for cultivating cotton.