Go through these RBSE Class 11 Indian Geography Notes Chapter 13 Rajasthan: Climate, Vegetation and Soil contain important concepts so that students can score better marks in the exam.
Rajasthan Board RBSE Class 11 Indian Geography Notes Chapter 13 Rajasthan: Climate, Vegetation and Soil
- The composite or generally prevailing weather conditions of a region for a long period (more than 30 years) is called the climate.
- Climate is a geographic factor which not only affects the natural elements, but also affects the economic and demographic elements.
- Each of the four divisions of the year (summer, winter, autumn and spring), marked by specific weather patterns resulting from the changing position of the earth in context to the sun.
- Temperature, atmospheric pressure, winds and rainfall are the elements of climate.
- On the basis of temperature, the world has been divided into three zones: Tropical zone, Temperate zone and Frigid zone.
- For the determination of climatic zones, rainfall plays an important role. On this basis, climatic zones are classified into Humid, Semi-humid and Arid climatic zones.
Climate of Rajasthan
- The climate of Rajasthan relates to Monsoon and it is arid and semi-humid.
- The climate of western Rajasthan is dry. In the eastern part of Aravalli, it is subhumid, and in Jhalawar and Mount Abu of the south-eastern Plateau area, it is excessively humid climate.
- The climate of a particular place is influenced by a variety of intersecting factors.
- The factors which influence climate are latitude, elevation, situation and location of Aravalli Mountain, ocean-currents, topography, soil, vegetative cover and prevailing winds.
Characteristics of Rajasthan’s Climate
- The climate of Rajasthan shows diversities throughout the state.
- In the desert areas, it is usually hot and dry in summers and cold during winters, in the Aravalli range to the west, both rainfall and humidity are low, and in the east, weather is characterised by high humidity and more rainfall.
Seasons of Rajasthan
- There are three seasons in Rajasthan-summer, rainy and winter.
- In the summer season, the atmospheric conditions in Rajasthan include high temperature, hot and dry winds (100) and storms.
- Rainy season is from mid June to September. During this period, there is maximum rainfall. Rajasthan receives rainfall from both Bay of Bengal branch and Arabian Sea branch.
- Winters in Rajasthan exist from October to February. There is low temperature, calm winds, lack of humidity etc. in Rajasthan at this time.
- Vegetation is the sum total of plant species and the ground cover they provide. The trees, plants, hurbs, shrubs and grasses found on the earth’s surface are collectively called vegetation.
- Vegetation plays an important role in balancing the environmental and ecological conditions.
- We obtain many direct and indirect benefits from forests.
Distribution of Forests
- The distribution of forest is only on 9.32 per cent of total area of Rajasthan.
- The dense forests are found only on 3.83 per cent area. The per person forest area in Rajasthan is only 0.03 hectare, which is extremely less than the national average of 0.13 hectare per person.
- There is dense vegetation in the districts of Sirohi, Banswara, Dungarpur, Udaipur, Rajsamand, Chittorgarh and Jhalawar, while very few and rare forests are seen in Churu, Nagaur, Jodhpur, and Barmer.
- Maximum forest area of 31 per cent is found in Sirohi, while the least 0.05 per cent is found in Churu district.
Types of Forests
- Geographical classification of forest is more important in Rajasthan due to the variation of topographical forms, climate and soils.
- On the basis of geographical classification, the forests found here are divided into tropical thorny forests, tropical dry autumn forests and sub-humid mountain forests.
- Tropical dry autumn forests have again been classified into dry teak, salar, bamboo, dhaukara, palash, khair, babool and mixed autumn forests.
- On the basis of administration, forests have been classified into Reserved forests, Protected forests and Unclassified forests.
- Soil is the material found on the Earth’s surface that is composed of organic and inorganic elements.
- Soil is the best natural gift on which the entire agricultural cultivation depends.
- Soils are formed due to the interaction of five major factors time, climate, parent material, topographical relief and organisms.
- Soil is a mixture of solid, liquid and gaseous substances which is a result of interaction of fragmentation of rocks, climate, vegetation and bacteria.
Types of Soil
- On the basis of colour, composition and fertility, the soils of Rajasthan have been divided into deserted sandy, red-yellow, laterite, combind red and black, black and alluvial soil.
- The formation of deserted sandy soil is due to high temperature and physical erosion, the formation of laterite soil is due to high temperature and excess humidity and the black soil is formed of lava-based rocks.
Problems of Soil
- The main problems of soil are erosion, degradation and water logging.
- Removal of top soil due to it being flown or blown away by the action of air and water is called soil erosion.
- The destruction of soil and its fertility is also called “creaping death.”
- Usually, the soil erosion is classified into sheet erosion, rill erosion and gully erosion.
- The main causes of soil erosion are rapid water flow, lack of vegetation, deforestation, uncontrolled grazing of animals, old methods of farming etc.
- The causes of degradation of soil include sustained agriculture and old unscientific methods of agriculture and water logging.
- The quality of soil may be retained only by its conservation. The main steps for soil conservation include the use of green manure, vermicompost, forestation and leaving the soil layered, etc.
Rajasthan: Climate, Vegetation and Soil Notes Important Terms
→ Climate: The composite or generally prevailing weather conditions of a region for a year or a series of the years.
→ Vegetation: Vegetation is the sum total of plant species and the ground cover they provide. The trees, plants, hurbs, shurbs and grasses found on the earth’s surface are collectively called vegetation.
→ Season: Each of the four division of the year (summer, winter, autumn and spring), marked by particular weather patterns, resulting out of the earth’s changing position in context to the sun.
→ Soil: Soil is the material found on the earth’s surface that’ is composed of organic and inorganic elements.
→ Atmospheric pressure: It is the force exerted on a point of the earth’s surface by the air above it as gravity pulls it to Earth. Atmospheric pressure is also called air pressure and it is measured commonly with a barometer.
→ Rain: Rain is liquid water in the form of droplets that have condensed from atmospheric water vapour and that become heavy enough to fall on the earth under gravity.
→ Tropical zone: Tropical zone is the region of Earth near the equator and between the Tropic of Cancer in the Northern Hemisphere and Tropic of Capricorn in the Southern Hemisphere.
→ Temperate zone: Temperate latitudes of the Earth lie between the subtropics and the polar circle.
→ Frigid zone: The area or region between the Arctic Circle and the North Pole or between the Antarctic Circle and the South Pole, where the earth’s surface is covered with snow during most of year due to very low temperature.
→ Humidity: Humidity is the amount of water vapour present in the air.
→ Aridity: Aridity is a term that most people conceptually understand, and it evokes an image of dry, desert land with sparse natural water bodies and rainfall and commonly only scant vegetation, which is adapted to scarcity of water.
→ Monsoon Climate: Monsoon is traditionally defined as a seasonal reversing wind accompained by corresponding changes in precipitation.
→ Range of Temperature: The difference between the maximum and the minimum temperature. It may be daily, monthly or annually.
→ Latitude: The angular distance of a place north or south of the earth’s equator or of the equator of a celestial object, usually expressed in degrees and minutes.
→ Loo: The Loo is a strong dusty, hot and dry summer wind blowing from the west which blows over the western Indo-Gangetic Plain region of North India and Pakistan.
→ Freezing point: The temperature at which a liquid turns into a solid.
→ Drought: A period of below-average precipitation in a given region, resulting in prolonged shortage of water supply, whether surface water or groundwater.
→ Marwar: The nearby region of Ajmer and Pali.
→ Tropic of Cancer: Latitude approximately 23°32′ North of the terrestrial Equator. This is the last border of the vertical position of Sun in the Northern Hemisphere, and in its north, the sunrays never fall vertically.
→ Sea: The expanse of saltwater that covers most of the earth’s surface and surrounds its landmasses or a body of saline water; not as large as an ocean and often nearly surrounded by land.
→ Bay or Gulf: A part of the coast where the land curves in so that the sea is surrounded by land on three sides.
→ Isohyet: A line drawn on a weather map connecting places that receive equal amount of precipitation during a given time period.
→ Semi-arid climate: It is a climate of a region that receives precipitation below potential evapotranspiration, but not as low as a desert climate region.
→ Desert: It is a large area of land usually in a hot region, where there is almost no water, rain, trees or plants.
→ Summer Season: It is the hottest temperate season, falling after spring and before autumn.
→ Rainy Season: It is the time of year, wherein most of the region’s average annual rainfall occurs due to the Monsoon winds.
→ Autumn: Autumn is the third season of the year, coming sifter summer and before winter and coinciding with the shedding of leaves from the trees as they go into a winter rest.
→ Winter Season: It is the coldest season of the year in polar temperate zone (winter does not occur in the tropical zone). It is caused by the axis of the Earth in the hemisphere being oriented away from the sun.
→ Mavath: The rainfall during the winter season, caused by temperate cyclones.
→ Environment : The surroundings or conditions in which a person, animal or plant lives or operates.
→ Ecology: The branch of biology that deals with the relationship of organisms with one another and with their physical surroundings.
→ Erosion: Removal of top soil or cutting of rocks due to various natural powers, which is mainly the result of transfer of air, flowing water, oceanic currents and glaciers.
→ Drainage: The flow of water according to the gradiant of the ground.
→ Industry: An economic activity concerned with the processing of raw materials and manufacturing of goods in factories.
→ Canal: A canal is a long man-made strip of water used for irrigation or boat access to a bigger body of water.
→ Autumn forests: The vegetation in which trees shed most of their leaves in the dry season to maintain moisture in it.
→ Evergreen Forests: Tropical evergreen forests are usually found in areas receiving more than 200 cm of rainfall and having a monthly average temperature of 18° C or heigher in the coldest months. They are dense, multi-layered and home to many types of plants and animals.
→ Reserved Forest: An area of forest set aside and preserved by the government as a wildlife national park or sanctuary and in which grazing of animals or wood-cutting is prohibited.
→ Conserved forests: The forest in which wood-cutting and animal grazing is permitted under some rules and regulations.
→ Unclassified forests: The forests where there is no boundation on wood-cutting and animal grazing.
→ Grazing: It is a method of feeding in which a herbivore feeds on plants such as grasses, or other multicellular organisms such as algae.
→ Agriculture: The science, art or occupation concerned with cultivating the land, raising crops and feeding, breeding and raising livestock.
→ Occupation: A person’s usual or principal work or business, especially as means of earning a living.
→ Relief: The difference between the highest and lowest elevation in an area that show. the topography of the area.
→ Humus: A dark-brown or black organic substance made up of decayed plant or animal matter.
→ Weathering: It is the breaking down of rocks-soils and minerals as well as wood and artificial materials through contact with the Earth’s atmosphere, water and biological organisms.
→ Physical weathering: Physical weathering is caused by the effects of changing temperature on rocks causing the rocks to break apart.
→ Salinity: Salinity is the saltness or amount of salt dissolved in a body of water.
→ Metamorphic Rock: Rock that was once a form of rock but has changed to another under the influence of heat, pressure, or some other agent without passing through a liquid phase.
→ Plateau: A plateau is a flat, elevated landform that rises sharply above the surrounding area on at least one side.
→ Shifting Agriculture: A form of agriculture practiced especially in tropical Africa, in which an area of ground is cleared of vegetation and cultivated for a few years and then abandoned for a new area until its fertility has been naturally restored.
→ Flood: An overflow of a large amount of water beyond its normal limits, especially over what is normally dry land.
→ Dam or Embankment: A barrier constructed to hold back water and raise its level, forming a reservoir used to generate electricity or for water supply.
→ Leaching: A natural process by which water-soluble substances (such as calcium, fertilizers, pesticides) are washed out from soil or wastes.
→ Conservation: Careful preservation and protection of something.
→ Soil Conservation: It is the prevention of soil loss from erosion or reduced fertility caused by over-usage, acidification, salinization or other chemical soil contamination.