Alluvial Soil Characteristics and Classification

Major Coverage Area: Alluvial soil covers the entirety of the Northern plains of India.
River Systems Responsible for Deposition: These soils are deposited by the three major Himalayan river systems: * The Indus * The Ganga * The Bramha putra (Note: Transcript spelling)
Geographical Corridors: The distribution of alluvial soil extends into the states of Rajasthan and Gujrat through specific narrow corridors.
Coastal Regions: In addition to the northern plains, alluvial soil is found in the eastern coastal regions, specifically within the deltas of the following rivers: * Mahanadi * Godavari * Krishna * Kaveri

General Components: Alluvial soil contains various proportions of the following three materials: * Sand * Silt * Clay
Inland Variations: The size of soil particles changes based on proximity to the river source. As one moves inland toward the river valleys, the soil particles appear somewhat bigger in size.
Characteristics of the Upper Reach: In the upper reaches of a river valley—specifically near the "break of slope"—the soils are characterized as being coarse.
Piedmont Regions: Coarse soils are particularly common in the plains of the piedmont regions (the area at the foot of mountains). Named examples of such regions include: * Duars * Chos * Terai

Alluvial soils are categorized into two primary types based on their age and proximity to the river:

Bangar (Old Alluvial Soil): * Location: It is found away from the river. * Composition: It features a higher concentration of "kankar nodules." * Fertility Level: It is classified as less fertile.
Khadar (Newer Alluvial Soil): * Location: It is found close to the river. * Composition: It contains more fine particles compared to the Bangar variety. * Fertility Level: It is more fertile than Bangar.

General Fertility: As a whole, alluvial soil is considered very fertile.
Nutrient Richness: These soils are characterized by an additional quantity of specific nutrients essential for plant growth: * Potash * Phosphoric acid * Lime
Alkaline Variation in Drier Areas: Soils located in drier geographical areas tend to be more variable and exhibit higher alkaline content.

Ideal Crops: Due to its nutrient composition, alluvial soil is perfect for the growth of: * Sugarcane * Paddy * Wheat * Pulse crops * Cereal crops
Population Density: Because of the high fertility of the soil, regions where alluvial soil is prevalent are intensively cultivated and densely populated.
Productivity Improvement: More alkaline soils found in drier areas are not stagnant; they can be made highly productive provided they undergo proper treatment and irrigation processes.