The document describes the different types of soils found in Assam, India. The main types discussed are alluvial soil, hill soil, lateritic soil, and piedmont soil. Alluvial soil is the most extensively distributed soil, found over river plains. It can be divided into younger alluvial soil near rivers and older alluvial soil further away. Hill soils in the southern hilly regions vary from red sandy to red loamy soils. Lateritic soils are found in the N.C. Hills district and parts of other districts. Piedmont soils are concentrated along the foothills of the Himalayas and include Bhabar and Tarai soils. The typical characteristics of Assam soils are acid

2. Clay soil is defined as soil that is composed of mostly clay
particles. Heavy clay soil, absent of sand or organic matter,
tends to hold a lot of water, particularly in winter when there is
less evaporation. Retains moisture well
Loam is soil composed of sand, silt, and clay in relatively
even concentration (about 40-40-20% concentration
respectively)

3. A soil in which sand predominates is sandy soil.
Sandy soils are coarse in texture. Drains easily and
quickly after a rain
Silt soil is finer than sand, but still feels gritty. Silt
is commonly found in floodplains

4. The diversified geological conditions, topographical
characteristics, climatic situations and vegetation
types have favor the formation of different types of
soil in Assam.
The most typical characteristics of Assam soil is
acidity, where pH of the soils generally ranges
between 4.2 to 5.8. Organic matter content of
majority soils is medium to high.
Types of soil: alluvial, laterite, hill soil and piedmont
soil

5. The alluvial soils are extensively distributed over the
Brahmaputra and Barak plain
Alluvial soil
These soils are very fertile as they formed from the
alluvium deposits, deposited by the rivers
Brahmaputra, Barak and their tributaries
The alluvial soils of Assam can be further be divided
into two sub-types base on some micro differences in
character such as – younger alluvium and old
alluvium.

6. The younger alluvial soil occurs in an extensive belt
of the north-bank and south-bank plains including
the active flood plains of the Brahmaputra and the
Barak rivers.
This soil characterized by recent deposition of
alluvium, moderately deep to very deep with grey to
molted grey colour. It is mostly composed of sandy
to silty loams and slightly acidic in nature.
The soil lack in profile development and is deficient
in phosphoric acid, nitrogen and humus.
Younger Alluvium

8. The old alluvial soil occurs in some patches of Kokrajhar,
Barpeta, Nalbari, Kamrup, Darrang, Sonitpur, Lakhimpur and
dhemaji districts
Older Alluvium
The Barak plain, has some elongated patches of old alluvial
soil confined between the new alluvial soils of the active
floodplain and the hill soils boardering Mizoram.
Generally the old alluvial soil is very deep, brownish to
yellowish brown with texture of fine loams to coarse loams
and is slightly to moderately acidic.

9. Hill Soils:
The hill soils are generally found in the southern hilly terrains
of the state. The fertility of these soils defers greatly in
different regions.
These soils are rich in nitrogen and organic matters.
On the basis of the physical texture and chemical
composition, the hill soils may be divided into red sandy soils
and red loamy soils.
The red sandy soils are distributed covering as narrow belt
along the Assam- Meghalaya border, the Karbi Plateau,
southern part of Barail range of the N.C.Hill district and
some parts of the foothills along the eastern border of the
Cachar district.

10. This soil is very deep and well drained, brownish to
yellowish in colour, strongly to moderately acidic with high
organic content.
The red loamy soils, on the other hand,
occurs in the narrow southern foothill
belt running along the Assams boarder
with Arunachal and Nagaland and also
in the southern fringes of the Karbi
Plateau and the Barail hills of N.C.Hills
district.
These soils are very deep, dark grayish brown to yellowish
red and fine to coarse loamy. Red loamy soils are slightly
to moderately acidic and these lack in nitrogen, phosphoric
acid, humus and lime.

11. Lateritic Soils
The lateritic soils in the state extensively occurs almost
entirely over the N.C.Hills district covering some parts of
southern Karbi Plateau while few patches are confined to
eastern margin of the Hamren sub-division of Karbe
Anglong district, southern boarder of Golaghat district and
the northern part of the Barak plain along the foothills of the
Barail range.
These soils are dark and
finely texture with heavy
loams and deficient in
nitrogen, potash,
phosphoric acid and lime.

12. The piedmont soils are concentrated to the northern narrow
zone along the piedmont zone of the Himalayan foothills.
These soils comprise the Bhabar soil and the Tarai soil,
covering respectively the Bhabar and the Tarai belt of the
Brahmaputra valley.
This soil is deep and fine to clay loamy in texture.
This soil varies from sandy to silty loams that remain
saturated and support tall grasses in a series of swamps.
Piedmont soils

14. Problem
SOIL DEGRADATION due to soil erosion and human intervantio.