Soil and Climate of Bihar


Soil is one of the most important resources of a nation. It is the gift of nature of immense value. The most common use of the word soil is in the sense of a medium in which plants grow, although it has a different connotation at different time and place, and for persons engaged in different professions. Almost all the economic activities are directly or indirectly dependent on soil. Thus soil is the backbone of agricultural and industrial development.

Soil has a number of characteristics, which may be regarded as the aggregate of the physical, chemical and biological properties. The Bihar plane consists of a thick alluvial mantle of drift origin overlying in most part. The siwalik and older tertiary rocks. The soil is mainly young loam rejuvenated every year by constant deposition of silt, clay and sand brought by different streams. This soil is deficient in phosphoric acid, nitrogen and humus, but potash and lime are usually present in sufficient quantity.

There are three major types of soil in Bihar:

Piedmont Swamp Soil – found in northwestern part of west Champaran district.
Terai Soil – found in northern part of the state along the border of Nepal.
The Gangetic Alluvium– the plain of Bihar is covered by gangetic alluvium (both new as well as old). 


The climate of Bihar is a part of the climatic pattern of the Indian subcontinent. It enjoys a continental monsoon type of climate owing to its great distance from the sea.


The factors affecting the climate of Bihar are:

It extends from 22-degree north to 27-degree latitude. Hence its location is tropical to sub tropical.
The Himalayan Mountains in the north have a significant bearing on the distribution of monsoon rainfall in Bihar.
Bihar joins the Ganga delta and Assam.

Seasons and their duration:

Cold weather season – December to February.
Hot weather season – March to May.
Southwest monsoon – June to September.
Retreating southwest monsoon – October to November.