This document discusses different types of problematic soils including acidic, saline, and alkali soils. It provides details on the characteristics and causes of each soil type as well as management practices. Acidic soils have a pH below 7 and are common in India. Saline soils contain excess salts and are found in certain states. Alkali soils have a high pH and hard layers. The document also covers physical properties of problematic soils such as soil crusting, water logging, erosion, and swelling.
3. The soil that causes additional problems from the
engineering point of view as a result of the
circumstances of its composition or change in
environmental conditions.
Problematic
soils
Acidic Saline Alkaline
4. The soil having pH less than 7 is called acidic soil.
Extremely acidic soil has pH between 4-4.75.
Out of 157 m ha of cultivable land in India, 49 m ha of
land are acidic.
Found in almost all states of India except Punjab,
Haryana, Rajasthan and Gujarat.
Crops grown: rice, mango, cashew, cowpeas, potato
and certain grasses.
5. Acidic parent material such as granite.
Leaching due to heavy rain fall.
Humus and other organic acids.
MANAGEMENT:
Adding pulverised limestone or dolomite limestone
increases soil pH.
Keep the area flooded.
6. The soil with excess salt is called saline soil.
Saline soils are found in Gujarat, AP, WB, Odisha, TN,
Andaman and Nicobar islands.
The pH is usually <8.5 and ESP <15.
Crops grown: cotton, alfalfa, cereals, sorghum, sugar
beet, wheat grass.
Causes : salts originate from the natural weathering of
minerals or from fossil salt deposits.
7. By applying more water in the root zone and leaching
the salts.
Salts can be moved away from the root zone to
locations in the soil other than below the root zone,
where they are not harmful.
8. Alkali soils are clay soils with high pH, a poor soil
structure and a low infiltration capacity.
They have a hard calcareous layer at 0.5-1m depth.
Alkali soil is found in parts of Gujarat, Rajasthan,
Punjab, Haryana, UP and Maharashtra.
Causes: it is due to the presence of soil minerals
producing sodium carbonate and sodium bicarbonate
upon weathering.
9. Deep ploughing and incorporating calcareous subsoil
into the top soil.
Ensuring much acidifying material in the soil.
These soils can be recovered grass cultures, organic
compost, waste hair and feathers, organic garbage
etc.,.
10. 1.SOIL CRUSTING:
The soils are weakly
aggregated soil structure
are easily broken by the
impact of rain drops
resulting in the formation of
clay at the soil surface.
The clay pan can prevent
the germination of
seedlings and arrest the
free exchange of gases
between the soil and
atmosphere.
11. 2.WATER LOGGING SOIL
Water logging refers to the
saturation of soil with water.
It is said to be water logged
when the water table of the
ground water is too high.
3.ERODED SOIL
The size of the particles are
largest and coarser in
texture.
It is granular and consists
of rock and mineral
particles.
12. 4.SWELLING SOIL
Swelling soil is the soil that
gives a significant
increase in size when
absorbed water.
The swelling ratio depends
on increasing dry density
and increase the
percentage of clay.