Different criteria have been applied to classify Indian soils, the outstanding being geology, relief, fertility, chemical composition and physical structure, etc. The soil color is black. Some alluvial soils are found in the Narmada and Tapi valleys. It is the most important type of soil found in the country as it covers about 40% of the total land. Krebs holds that the regur is essentially a mature soil which has been produced by relief and climate, rather than by a particular type of rock. Angadipuram is also well known as a pilgrimage centre for its famous temples, the Thirumandhamkunnu temple and the Tali temple.
Large surface of soil particles: - Small clay particles have a large surface area compared to sand particles. The 7th approximation defines soil classes strictly in terms of their morphology and composition as produced by a set of natural and human forces. It, very soon after, becomes as hard as brick, and resists air and water much better than any bricks that I have seen in India… In the midland region of Kerala where is predominant, laterites form a residual deposit due to weathering of either crystalline or sedimentary rocks with thickness varying from 5—8 metres 16—26 ft. But it has the high content of humus. This type of soil is formed in the region of humid in the souls.
The states where this type of soil can be found are West Bengal, Andhra Pradesh, Bihar, Meghalaya, Assam, Odisha to name a few. In the drier areas or deciduous forest belt, deep soil, brown in colour and rich in humus is found. Rocks are leached by percolating rain water during the wet season; the resulting solution containing the leached ions is brought to the surface by during the dry season. Sr No Test Unit Obtained Results Protocol 1 Loss on Ignition % 11. In 1957, The National Atlas Organisation Kolkata published a soil map of India in which Indian soils were classified into 6 major groups and 11 broad types.
The proportion of the key ingredients determines the type of soil. The residue is pitted and porous in appearance. Black soil is extremely fine and clayey and has the capacity to hold a lot of moisture. As a general rule, black soils of uplands are of low fertility but they are darker, deeper and richer in the valleys. This type of soil is especially suited in the cotton cultivation. The has employed this system to rehabilitate degraded laterite soils in and increase smallholder farmers' incomes.
The average chemical composition of bauxite, by weight, is 45 to 60% Al 2O 3 and 20 to 30% Fe 2O 3. This type of soil is normally deficient in nitrogen and is poor in lime content; it is an acidic soil. This involves using indigenous water-harvesting methods such as planting pits and trenches , applying animal and plant residues, and planting high-value fruit trees and indigenous vegetable crops that are tolerant of drought conditions. Worldwide resources inventory indicates that laterites are a major source of nickel and account for 70% of resources. Bauxite patches are found with laterites overlying for a thickness varying from about 1—50 metres 3.
Laterite is a soil and rock type rich in iron and aluminium, and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. It is the topmost layer of the earth's crust and is a mixture of fine powdered rocks, organic matter, liquids, myriad organisms and other minerals. It is rich in potash content but lacks phosphate, humus and nitrogen content. But nickel production from this source is limited to about 40% of the total world production. Nickel laterites occur in zones of the earth which experienced prolonged tropical weathering of containing the ferro-magnesian minerals , , and.
Historically, laterite was cut into brick-like shapes and used in monument-building. Geographically, black soils are spread over 5. It is generally sandy and has gravels. These soils require fertilizers for agricultural purposes. Nitrogen is originally low but its deficiency is made up to some extent by the availability of nitrogen in the form of nitrates. Location, morphology and composition of laterite soils 5. Its occurrence extends to , , , , and districts.
Nearly all laterites are of rusty-red coloration, because of high content. This soil is derived from the early metamorphic rocks of the Deccan Plateau. Stabilization of laterite soils 19. Proceedings of the Institute of Natural Sciences, Nihon University. So the soil is the most precious resource in India. However, in large areas of desert soils, only the drought resistant and salt tolerant crops such as barley, rape, cotton, wheat, millets, maize and pulses are grown. In general in forest soil, as the trees have different root system unlike grasslands, the chance of that to decay and get added as humus in the soil is less.
This area is covered by a mantle of sand which inhibits soil growth. The characteristics of soil-forming minerals and rocks 2. The porosity and texture provide good drainage and other conditions favourable for bumper crops. The main host minerals for nickel and can be either , or. These soils are heterogeneous in nature and their character changes with parent rocks, ground-configuration and climate. This type of soil is mainly found in the western regions of Kottayam and Alappuzha district. The laterite profile over pyroxene granulites, metaultramafites and gneisses are characterised by relict foliation that conforms to those of the subjacent rocks which indicate the nature of the laterite.
It shows that laterite soils are different from natural soils and that most laterite soils can be evaluated for engineering purposes using accepted theories and well-known test procedures for temperate-zone soils. In the Ganga plain, there are two types of the Alluvium. Therefore, they require good deal of fertilizers for high yields. It comes sand in large quantities and is suitable for the cultivation of crops like Jowar and bajra. The soil content has 90-95% of sand and 5-10% of clay.