**In igneous and
metamorphic rocks minerals may occur in the cracks, crevices, faults or joints.
The smaller occurrences are called veins and the larger are called lodes.
In most cases, they are formed when minerals in liquid/molten and gaseous forms
are forced upward through cavities towards the earth’s surface. They cool and
solidify as they rise. Major metallic minerals like tin, copper, zinc and lead
etc. are obtained from veins and lodes.
In sedimentary
rocks a number of minerals occur in beds or layers. They have
been formed as a result of deposition, accumulation and concentration in
horizontal strata. Coal and some forms of iron ore have been concentrated as a
result of long periods under great heat and pressure. Another group of
sedimentary minerals include gypsum, potash salt and sodium salt. These are
formed as a result of evaporation especially in arid regions.
**Iron:
Magnetite is the finest
iron ore with a very high content
of iron up to 70 per cent. It has excellent magnetic
qualities, especially valuable in the electrical
industry. Hematite
ore is the most important
industrial iron ore in terms
of the quantity used, but has a slightly
lower iron content than magnetite. (50-60 per cent).
The major
iron ore belts
in India are:
Orissa-Jharkhand belt: In Orissa high grade hematite ore is found in Badampahar
mines in the Mayurbhanj and Kendujhar
districts. In the adjoining Singbhum
district of Jharkhand haematite iron ore is mined in Gua and Noamundi.
Durg-Bastar-Chandrapur belt lies in Chhattisgarh and Maharashtra. Very high grade hematites are found in the famous Bailadila
range of hills in the Bastar district
of Chattisgarh. The range of hills comprise
of 14 deposits of super high grade hematite
iron ore. It has the best physical properties
needed for steel making. Iron ore from these
mines is exported to Japan and South Korea via Vishakapatnam port.
Bellary-Chitradurga-Chikmaglur-Tumkur belt in Karnataka
has large reserves
of iron ore. The Kudermukh
mines located in the Western Ghats of Karnataka are a 100 per cent export
unit. Kudremukh deposits are known to be one of the largest
in the world.
The ore is transported as slurry through a pipeline to a port near Mangalore.
• Maharashtra-Goa belt includes the state
of Goa and Ratnagiri district
of Maharashtra. Though, the ores are not of
very high quality, yet they are efficiently
exploited. Iron ore is exported through
Marmagao port.
**Manganese
Manganese is mainly used in the manufacturing of steel and ferro-manganese
alloy. Nearly 10 kg of manganese
is required to manufacture one tonne of steel. It is also used in manufacturing bleaching powder, insecticides and paints.
Orissa is the largest producer of manganese
ores in India.
**Copper
Being malleable, ductile
and a good conductor, copper is mainly used
in electrical cables,
electronics and chemical
industries. The Balaghat
mines in Madhya Pradesh produce
52 per cent of India’s copper. The Singbhum district
of Jharkhand is also a leading producer of copper. The Khetri
mines in Rajasthan are also famous.
**Bauxite
Though, several ores contain aluminium, it is from bauxite,
a clay-like substance
that alumina and later aluminium
is obtained. India’s
bauxite deposits are mainly found
in the Amarkantak plateau,
Maikal hills and the plateau region of Bilaspur- Katni. Orissa is the largest bauxite producing
state in India with 45 per cent of the country’s
total production in 2000-01. Panchpatmali deposits in Koraput district are the most important bauxite deposits in the state.
**Coal:
Decaying plants
in swamps produce peat. Which has a low carbon and high moisture contents and
low heating capacity. Lignite is a low grade brown coal, which is soft
with high moisture content. The principal lignite reserves are in Neyveli in
Tamil Nadu and are used for generation of electricity. Coal that has been
buried deep and subjected to increased temperatures is bituminous coal.
It is the most popular coal in commercial use. Metallurgical coal is high grade
bituminous coal which has a special value for smelting iron in blast furnaces. Anthracite
is the highest quality hard coal.
**Nuclear or Atomic Energy is obtained by altering
the structure of atoms. When such an
alteration is made, much energy is released
in the form of heat
and this is used to
generate electric power. Uranium and thorium, which are available
in Jharkhand and the Aravalli ranges of Rajasthan are used for generating
atomic or nuclear
power. The Monazite sands of Kerala is also rich in thorium.
**The largest solar plant
of India is located at
Madhapur, near Bhuj, where solar energy is used to sterlise milk cans.
**The largest wind farm cluster is located
in Tamil Nadu from Nagarcoil to Madurai.
**In India,
the Gulf of Kuchchh, provides ideal
conditions for utilising tidal energy. A 900 mw tidal energy power plant is set up here by the
National Hydropower Corporation.
**Geothermal
Energy-One is located in the Parvati valley near Manikarn in Himachal Pradesh and the other
is located in the Puga Valley,
Ladakh.
**Primitive
Subsistence Farming: Jhumming(Farmers clear a patch of land and produce cereals and other food crops
to sustain their family. When the soil fertility decreases, the farmers shift
and clear a fresh patch of land for cultivation. This type of shifting allows
Nature to replenish the fertility of the soil through natural processes; land
productivity in this type of agriculture is low as the farmer does not use
fertilisers or other modern inputs): The ‘slash and burn’ agriculture is
known as ‘Milpa’ in Mexico and Central America, ‘Conuco’ in Venzuela, ‘Roca’ in
Brazil, ‘Masole’ in Central Africa, ‘Ladang’ in Indonesia, ‘Ray’ in Vietnam.
**Intensive
Subsistence Farming This
type of farming is practised in areas of high population pressure on land. It is
labour intensive farming, where high doses of biochemical inputs and irrigation
are used for obtaining higher production.
**Commercial
Farming The main characteristic of this type of farming is the use of
higher doses of modern inputs, e.g. high yielding variety (HYV) seeds, chemical
fertilisers, insecticides and pesticides in order to obtain higher
productivity. The degree of commercialisation of agriculture varies from one
region to another.
**Rabi crops are sown in winter from
October to December and harvested in summer from April to June. Some of the
important rabi crops are wheat, barley, peas, gram and mustard. Though, these
crops are grown in large parts of India, states from the north and northwestern
parts such as Punjab, Haryana, Himachal Pradesh, Jammu and Kashmir, Uttaranchal
and Uttar Pradesh.
**Kharif crops are grown with the onset
of monsoon in different parts of the country and these are harvested in
September-October. Important crops grown during this season are paddy, maize,
jowar, bajra, tur (arhar), moong, urad, cotton, jute, groundnut and soyabean.
Some of the most important rice-growing regions are Assam, West Bengal, coastal
regions of Orissa, Andhra Pradesh, Tamil Nadu, Kerala and Maharashtra.
**In between the
rabi and the kharif seasons, there is a short season during the summer months
known as the Zaid season. Some of the crops produced during ‘zaid’ are
watermelon, muskmelon, cucumber, vegetables and fodder crops. Sugarcane takes
almost a year to
grow.
**Rice: It
is the staple food crop of a majority of the people in India. Our country is
the second largest producer of rice in the world after China. It is a kharif
crop which requires high temperature, (above 25°C) and high humidity with
annual rainfall above 100 cm. In the areas of less rainfall, it grows with the
help of irrigation.
**Wheat: This
is the second most important cereal crop. It is the main food crop, in north and
north-western part of the country. This rabi crop requires a cool growing
season and a bright sunshine at the time of ripening. It requires 50 to 75 cm
of annual rainfall evenly distributed over the growing season.
**Bajra grows well on sandy soils and
shallow black soil. Rajasthan is the largest producer of bajra followed by
Uttar Pradesh, Maharashtra, Gujarat and Haryana. Ragi is a crop of dry regions
and grows well on red, black, sandy, loamy and shallow black soils. Karnataka
is the largest producer of ragi followed by Tamil Nadu. It is a kharif crop
which requires temperature between 21°C to 27°C and grows well in old alluvial
soil. In some states like Bihar maize is grown in rabi season also.
**Pulses need less moisture and survive
even in dry conditions. Being leguminous crops, all these crops except arhar
help in restoring soil fertility by fixing nitrogen from the air.
**Sugarcane:
It is a tropical as well as a subtropical crop. It grows well in hot
and humid climate with a temperature of 21°C to 27°C and an annual rainfall
between 75cm. and 100cm. Irrigation is required in the regions of low rainfall.
It can be grown on a variety of soils and needs manual labour from sowing to
harvesting. India is the second largest producer of sugarcane only after
Brazil.
**Groundnut is a
kharif crop and accounts for about half of the major oilseeds produced in the
country. Andhra Pradesh is the largest producer of groundnut followed by Tamil
Nadu, Karnataka, Gujarat and Maharashtra – linseed and mustard are rabi crops.
Sesamum is a kharif crop in north and rabi crop in south India. Castor seed is
grown both as rabi and kharif crop.
**Coffee: India
produces about four per cent of the world’s coffee production. Indian coffee is
known in the world for its good quality. The Arabica variety initially brought
from Yemen is produced in the country.
**Rubber: It
is an equatorial crop, but under special conditions, it is also grown in
tropical and sub-tropical areas. It requires moist and humid climate with
rainfall of more than 200 cm. and temperature above 25°C.
**Rearing of
silk worms for the production of silk fibre is known as sericulture.
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