GEOGRAPHY OF ASSAM (IX)

       Geography of Assam

       Chapter 4

1.write about the location of Assam.

Ans:Assam is a state of India located in the north-eastern region. On the boundary of this state lies seven states of India and two foreign countries- Bhutan and Bangladesh. Bhutan and Arunachal Pradesh are on the north of Assam; Arunachal Pradesh, Nagaland and Manipur are on the east; Mizoram and Meghalaya are on the south and Tripura, Bangladesh and West Bengal are on the west. Geographically the state extends from 24°09'N latitude to 27°58'N latitude and from 89°42/E longitude to 96°01'E longitude.

2.Write about the Important seasons of Assam.

Ans:Based on differences in the condition of climatic elements of different times in a year mainly four climatic seasons have been identified in Assam. These seasons include Pre-Monsoon, Monsoon, Retreating Monsoon and Dry Winter.

a)Pre-Monsoon Season: The pre-monsoon season in Assam prevails during early March to the end of May. As this season starts immediately after winter, since the beginning the atmospheric temperature starts increasing slowly. During the period of pre-monsoon the morning is pleasant, scorching mid-day, tiring afternoon, and sudden rainfall with lightning and thunder sometimes in the evening or night. Some kind of unstable atmospheric condition prevails during this season and sometimes dust storms and rainfall with thunder occur. With the passage of time high amount of rainfall starts occurring more frequently. Occurrence of this rainfall before monsoon helps in the cultivation of paddy, tea and jute in the state. During the period of pre-monsoon spring season prevails in Assam. Bohag Bihu (festival of Assamese new year) or Rongali Bihu (festival of joy) is celebrated in the middle of April in the state.

b)Monsoon Season: Monsoon season generally prevails during. early June to end of September in Assam. This is the rainy season in Assam. During this period moderate to heavy rainfall occurs under the influence of south-west monsoon wind almost continuously in different places of the state. June, July and August are the months of maximum rainfall during monsoon. It may be mentioned that of the total annual rainfall in Assam (on the average about 200 cm) about 70 per cent occurs during these three months only. During this monsoon Assam's main crop Sali paddy is transplanted. Besides, due to the occurrence of heavy rainfall in most parts of the state including the surrounding hilly areas the water level of the Brahmaputra and Barak and their tributaries rises and often create floods.

c)Retreating Monsoon Season :The south-west monsoon wind starts withdrawing from the end of September. It means there is decrease of temperature and rainfall in this season following the end of rainy season. As a result of decreasing temperature air pressure in the state begins to increase and thereby the wind direction completely gets reversed and blows from north-east to south-west. This is called northeast monsoon or retreating monsoon. Generally retreating monsoon season prevails in Assam during October and November for two months. During this time period formation of fogs occurs in the night and morning due to temperature decrease. 

d) Dry Winter Season: Winter season prevails in Assam during the end of November or beginning of December to the end of February. The characteristics of winter season in Assam are low temperature (below 10°C), thick clouds in the morning, and a very dry condition due to lack of rainfall. That is why the months of December and January are very dry and the month of January is too cold. During this winter season Sali paddy is harvested and Bhogali or Magh Bihu is celebrated.

3) Write about the types of forests.

Ans: The forests of Assam may be divided into five main types. They are as follows:

A)Tropical Evergreen Forest : This type of forest is seen in the areas of high rainfall. Such forests are also called rain forest as these occur in the areas having a yearly rainfull of 300 cm or more. These forests are found to occur in the foothills close to Arunachal Pradesh, the southern parts of Tinsukia and Dibrugarh districts and some e to Arul hilly areas of the Barak valley.

           Generally the evergreen forests occur with three layers. The first layer is composed of very tall trees. In the evergreen forests of Assam, very tall trees like Holong and Mekai are found. The second layer is formed by some shorter trees like Nahar, Chiya Nahar, Amari etc. The third layer is composed of short trees and grasses. Besides trees, a variety of climbers, bamboos, canes and orchids are found in the evergreen forests. At present, this type of forests has been badly reduced in size due to several causes.

B) Tropical Semi-evergreen Forest: This type of forest is found to occur in the northern Bhabar zone of the Brahmaputra valley, parts of the hilly Karbi Anglong and Dima Hasao districts and the southern part the Barak valley. The soils of the Bhabar zone are composed of the sands and pebbles transported by the streams coming down from the Himalayas. These soils are loose in structure. Such an environment is fabourable for the semi-evergreen forest. The main species of these forests include Nahar, Bonchom, Cham, Sirish, Ou, Gandhsoroi, Agaru, Poma etc. Bamboos and canes, ferns etc, are abundantly found in these forests. However, the semi-evergreen forests are getting highly disturbed due to the expansion of settlements and roads to the foothill zones.

Tropical Moist Deciduous Forest : In certain parts of lower Brahmaputra valley, Karbi Anglong and Dima Hasao districts and the Barak valley, tropical moist decidious forests  occurs. Generally the areas having yearly rainfall of 200-250 cm favour the growth of this forest. Most of the trees of this type of forests shed their leaves during the winter. The trees which shed leaves during winter are called deciduous trees. Sal, Makori Sal, Gomari, Amlokhi, Bhomora, Gohara, Khokon, Simul are the dominant trees of the most deciduous forest. Sal forests are mostly seen in the slightly higher lands of south Kamrup and Goalpara district.

Riverine Forest : Assam is basically a land of rivers. The natural environment of the state is to a large extent, dominated by the rivers and wetlands. A special type of forest is generally seen in the wet peripheries of the rivers and wetlands which may be called reverine forest.

Once a large part of Assam was covered by reverine forests. This type of forest is dominated by some tall trees and grasses. Among the trees, Chom, Showalu, Uriam, Moz, Ou, Ajar are important. However, the riverine tracts are very favourable for grasses and bushy vegetations like Nal, Khagori, Tora, Koupat, cane, Jao, Kohua etc. Kaziranga, DibruSaikhoa and Orang national parks and Pabitora wildlife sanctury are located maintly in the riverine tracts. However, due to the expansion of human settlements to the riverine areas these forests are getting reduced in size rapidly.

E) Tropical Dry Deciduous Forest : Generally, in the relatively dry floodplains slightly away from the rivers, this type of forest is seen. Two different groups of plant are found here - considerably tall trees and grasses. The dominant trees include Sisoo, Bhelkor, Simul, Khair and Bogori etc. Birina, Khagori, Ulu, Khush etc. are the dominant grass species. The dry deciduous forests mainly occur in the dry sandy areas close to the wet riverine forest areas. This type of forests is also getting rapidly degraded due to the gradual expansion of settlements to the riverine tracts.

In addition to the above mentioned types of forests, some other types also occur in certain areas of the state.Likewise, the pine forest scattered in the high hills or Karbi Anglong and Dima Hasao districts .Moreover ,short bushy vegetations are found to occupy the forests are called degraded forests. Degraded forests are commonly seen in most of the districts of Asam.

4.When was the Sylhet part separated from Assam and joined East Pakistan?

Ans:In 1947.

5.When was Nagalnd separated from Assam?

Ans: In 1963.

6.When was Mghalaya separated from Assam?

Ans: In 1970.

7.When was Mizoram separated from Assam?

Ans:In 1971.

8.When was the capital city of Assam established in Dispur?

Ans: In 1973.

9.What is the total land area of Assam?

Ans: 78,438 km square.

10.How many districts are there in Assam, at present?

Ans: 35 districts.

11.What is the full form of BTAD?

Ans:The full form of BTAD is Bodoland Territorial Area Districts.

12.Which areas are fall under the BTAD?

Ans: Kokrajhar, Chirang, Baksa and Udalguri.

13. Which  is the largest district of Assam , in respect of land area?

Ans: Karbi Anglong.

14. Which  is the smallest district of Assam , in respect of land area?

Ans: Kamrup Metropolitan.

15.Which  is the largest district of Assam , in respect of population?

Ans: Nagaon.

16.Which  is the smallest district of Assam , in respect of population?

Ans: Dima - Hasao.

17. How many national parks are there at present?

Ans: 7 national parks.

National Parks	Location ( districts)
Kaziranga National Park	Golaghat,Nagaon and Sonitpur
Manas National Park	Chirang and Baksa.
Orang National Park	Odalguri and Sonitpur
Nameri National Park	Sonitpur
Dibru – Saikhowa National Park	Dibrugarh and Tinsukia
Raimora National Park	Kokrajhar
Dihing- Patkai National Park	Dibrugarh and Tinsukia

18. Name of Wildlife Sanctuaries.

Ans:

Wildlife Sanctuaries	Location
Amchang	Kamrup ( Metro)
Burachapori	Sonitpur
B.B. Podumoni	Tinsukia
Bornadee	Udalguri
Borali	Cachar and Karimganj
Chakrashila	Kokrajhar
Deepar Beel	Kamrup ( Metro)
East Karbi Anglong	Karbi Anglong
Garampani	Karbi Anglong
Hollongpara	Jorhat
Laokhowa	Nagaon
Nambor	Karbi Anglong
Morat - Longri	Karbi Anglong
Nambor Doigurang	Golaghat
Pobitora	Morigaon
Panidihing	Sivsagar
Sonai- rupai	Sonitpur

19) Write about the types of soils.

Ans: The soils of Assam can be classified into four types, such as- 

a) Alluvial soil: The alluvial soils are extensively found in the plains of the Brahmaputra and Barak Valleys. These soils have formed as a result of deposition of silt and clays carried by the rivers and their tributaries. Alluvial soils are generally fertile. These are of two types- (a) New Alluvial soil and

b) Old Alluvial soil.

b) Piedmont soil:The piedmont soils are confined to the northern narrow zone along the piedmont zone of the Himalayan foothills. The piedmont zone consists of the Bhabar and the Tarai belts. The Bhabar belt extending in east-west direction along the Assam-Arunachal Pradesh border is formed by a series of alluvial cones. The soils of this belt are composed of unassorted materials of boulders, pebbles sands and silts. These soils have deep to very deep layers. On the other hand, the soils of the Tarai belt occuring just south of the Bhabar belt generally remain saturated with water.Therefore, these soils support tall grasses.

c) Hill soil: The hill soils are generally found in the southern hill areas of Assam. Fertility of hill soils differs from place to place. Nitrogen and organic materials are abundant in these soils. Based on physical structure and chemical properties, these soils can be divided into two types, viz. red sandy soils and red loamy soils. The red sandy soils are found especially in  the Assam -Meghalaya boarder region, Karbi plateau, southern part of the Barail range in the North Cachar Hills district and some parts of the foothills along the eastern boundary of the Cachar district. These soils are formed mainly due to erosion of rocks and their layers are deep. These are strongly to moderately acidic with high organic content. On the other hand, the red loamy soils are found in the narrow belt on the south of the Assam-Arunachal border, Karbi Plateau and also in the southern part of the Barail range in the North Cacher Hills district. These soils also occur in some amount along the Assam-Mizoram border areas. The soils are deep and composed of fine to coarse sand, silt and clay. These soils are slightly to moderately acidic and these contain nitrogen, phosphoric acid, humus and lime in little amount.

 4) The laterite soil  soils are found in almost entire North Cachar Hills district and in some southern parts of the Karbi Plateau. Moreover, these soils are also available in the eastern border of the Hamren sub-division of Karbi Anglong district, southern border of Golaghat district and the foothills of the Barail range in the northern part of the Barak plain. Generally, these sorts are black in colour and their texture is sandy. These soils contain less amount of nitrogen, potash, phospheric acid and lime. 

20) What are the factors responsible for soil degradation?

Ans:The factors which responsible for soil degradation are- 

a) Physical factors:

i) the soil erosion on the hill slopes due to natural causes and 

ii) water logging problems created on the plains and low- lying areas.

b) Human factors:

a) surface soil erosion caused by increased surface waterflow due to tree felling etc.

b) cultivation of land on hill slopes in unscientific manner.

c) jhum cultivation done in the hill areas.

d) water logging created as a result of human settlements and other activities and 

e) use of chemical fertilizers in soils in order to increase more crop production.

21) Which state is known as a land of jungles?

Ans: Assam .

22.Write about the types of Alluvial soil.

Ans: Alluvial soils are generally fertile. These are of two types-

 (a) New Alluival soils and 

(b) Old Alluvial soils. 

a) New Alluvial soils: The new alluvial soil are mostly found in the active floodplains of the Brahmaputra and Barak rivers and their tributaries and also in the river side plains. These soils are moderately deep and grey in colour. These are basically composed of sandy to silty loams and slightly acidic. On the river banks, these are sometimes neutral or slightly alkaline. These soils are deficient in phosphoric acid, nitrogen and humus.

b)The old Alluvial soil: The old alluvial soils are found especially in the regions between the northern piedmont zone of the Kokarjhar, Barpeta, Nalbari, Kamrup, Darrang, Sonitpur, Lakhimpur and Dhemaji districts and the new alluvail soils of the south bank of the Brahmaputra. Similarly these soils are found in the regions of the south bank districts lying between the southern hill soil zone and the new alluvial soil zone along the Brahmaputra river. Old alluvial soils occur extensively in the plains of the Kopili river in Nowgong district. On the other hand, these soils are available in a narrow zone of the Barak plain between the active floodplain of Barak and the hill soils of the Assam-Mizoram border. Generally, the layers of the old alluvial soils are deep and brown in colour. These soils are more or less acidic and composed of fine to coarse loams.

23) Write about the major physiographic divisions of Assam.

Ans: The major physiographic divisions of Assam are:

a) The Brahmaputra Valley:

(a) The Brahmaputra Valley: The Brahmaputra Valley is a major physiographic unit of Assam. This valley is long and narrow. It is about 720 km. long and about 80km. wide on the average. It is bounded by hills and plateaus on its three sides north, east and south. The Eastern Himalayas lie on its north and east and the Naga hills, Karbi and Meghalaya plateaus lie on the south. It is open in the west merging with the plains of West Bengal and Bangladesh. The 640 km long reach of the Brahmaputra and its large number of north and south bank tributaries drain this valley. The Brahmaputra valley covers about 72 per cent of the total area of Assam. The valley generally slopes from north-east to south-west with an average gradient of 13 cm per km. However, in its upper reach near Dibrugarh, the gradient is about 17 cm per km., while the same is about 10 cm per km. in its lower reach near Guwahati.

b) The Barak Valley:Like the Brahmaputra Valley, the Barak Valley is also an important physiographic region of Assam. The Barak valley region consists of the Barak plain and its adjacent northern and southern foothills. The river Barak flows for 225 km in Assam from east to west through Cachar district and along the northern boundary Hailakandi and Karimgang districts. The Barak plain has been created through deposition of alluvial sediments carried by the river Barak and its tributaries from the hills in the north and the south. This plain is also known as Cachar plain. It is enclosed by hill ranges on its northern, southern and eastern sides. There are Meghalaya Plateau and the Barail ranges of the North Cachar Hills district on the north, Manipur hills on the east and the Mizo hills on the south. However, this plain is open on the west merging with the Kushiyara- Surma plain of the Sylhet district of Bangladesh. The important north bank tributaries of the Barak river are Chiri, Diksa, Digli, Jiri, Madhura, Jatinga, Larang, etc. Its important south bank tributaries are Sonai, Dhaleswari -Katakhal, Singla, Langai etc. 

(c) The Karbi Plateau: Based on its origin and geological formation the Karbi Plateau can be said to be a part of the Meghalaya Plateau. The Kopili valley has divided the Karbi Plateau in to two parts the eastern part and the western part: The eastern part covered by the Rengma hills spans over the entire Diphu and Bokajan subdivisions of Karbi Anglong district. It is approximately double the size of the western part. On the other hand, the western part covers the Hamren sub-division of the district. This part has an average height of 900 m and it slopes from south-west to north-east. The physiography of this part of the Karbi plateau has developed as a result of the works of the rivers Kopili and Barapani and their tributaries.

(d) The Barail and the southern Hills: The part of the Barail range extending westward from Thensang acroos Nagaland spans over the North Cachar Hills district of Assam. Actually, the Barail range has connected the Naga hills in the east with the Meghalaya Plateau in the west. This range has also divided the North Cachar Hills region into two parts. The north-sloping part falls within the Brahmaputra valley, while the south - sloping part falls within the Barak valley. The north - sloping part is relatively lower than the south - sloping part.