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It is a vertical series of soil horizons from the ground surface to the parent rock. The profile results from the same parent rock having similar horizons and soil profiles, but with varying characteristics according to their location (Fig. 6.2).
India is a vast country having great variations in its terrain and climatic conditions. The geo-climatic conditions of India have affected the general distribution of soils, their texture, structure, colour, pH value, and porosity. In general, the soils of India follow the climatic and vegetation belts.
Soil is formed under specific natural conditions and each of the elements of the natural environment contributes to this complex process described by soil scientists as the process of pedogenesis or soil f ormation. The soil of a place is closely influenced by the nature of parent rock, surface features of relief, climatic conditions, natural vegetation, land use practices, organisms, insects, microorganisms (bacteria), and time. These factors do not act on soil independently or in isolation, but in close association with each other leading to a whole network of inter-relationships of quite a complex nature. The material for soil formation, termed by soil scientists as the parent material, is derived from the rocks exposed on the surface. The relief and characteristics of slope along with the work of the various agents of weathering, determine conditions for the disintegration of the rock materials. Thus, the original soil characteristics, including the chemical constituents, are borrowed from the rock below. Soils may be transported by running water, wind or other agents of erosion, or may remain in the original position. When soil remains in its original position, it is said to be in situ, and in that state it is further modified by the climate, particularly moisture supply, plant growth and bacterial activity dependent on these factors.
As a natural resource, soil is of immense value to humans. Its nature and fertility determines the agricultural productivity on which depends the carrying capacity of the soil and the level of development of the rural communities.