4. SOIL
⢠The unconsolidated mineral material on the surface of
the earth in which plants grow. It has formed as a result
of various soil forming factors and processes.
⢠It differs from the parent material in many
physical,chemical,biological and morphological
properties.
5. MAJOR SOILS OF INDIA
⢠Alluvial soil 75 Mha
⢠Black soils 72 Mha
⢠Red soils 70 Mha
⢠Laterite soil 25 Mha
⢠Saline and alkali soils 7.5 Mha
⢠Desert soils 29 Mha
6.
7. ALLUVIAL SOILS
⢠Alluvial soils are most fertile and important group
of soils for agricultural production.
⢠The most recent,young alluvial
(khadar),,,,,subrecent,old alluvial (bhangar).
⢠Soils are deficient in N,P and humus.
9. Black(cotton) soils
⢠Very dark in colour,turn extremely hard in drying and sticky
and plastic on wetting, and hence are very difficult to
cultivate and manage.
⢠Black soil developed on basaltic material, Clay ranging from
30-80%.
⢠Develop typical cracks that are 1cm wide and reach a depth
of 50cm. Or more ,known as heavy,cracking clay soils.
10. Soil
⢠As per the genetic system,are classified in the
orders of intrazonal , REGUR( black soil).
⢠black soil group is self-mulching and crusty .
Azonal , REGOSOLS,alluvial soils.
11.
12. Desert (Arid) Soils
⢠Soil show a salic, gypsic, calcic, petrocalcic or a duripan.
⢠sink-holes and sand dunes related to desert soils.
⢠the name desert/arid is given to the soils that support
almost negligible vegetation,except xerophytic plants unless
irrigated.
⢠These are the soils of dry places that represent aridic/torrid
moisture regime.
13.
14. Red soils
⢠Hues of 7.6YR of red soils.
⢠These are red to yellowish colour which is the
result of coating of Cedric oxides on soil-ped
surfaces,rather than to a very high proportion of
iron.
16. Laterite and lateritic soils
⢠The term laterite coined and used by Buchanan.
⢠the laterites are typically formed in tropical and
subtropical climate.
⢠These soils are dominant in kaolinite clay mineral,that is
formed due to neosynthesis.gibbsite is common
observed in laterites.
18. Salt affected soils
⢠In the arid and semi-arid regions,due to high
evaporative demand,the dissolved soluble
salts(sodium,potassium,calcium,magnesium as
chloride,Sulphates and bicarbonates).
⢠Sodic/alkali Soil reclaimed by using gypsum ,other
amendement I.e. , calcium chloride,sulphur,iron
sulphate ,iron pyrite etc.
19. CLASSIFICATION OF SALT AFFECTED
SOILS
⢠Class EC dSm-1 pH (s) ESP Genetic sys.
¤saline >4 <8.5 <15 solonchaks
¤saline- >4 >8.5 >15
sodic
¤Sodic <4 >8.5 >15 Solonetz.
22. Podzolic soils
⢠The soils,formed under cool temperate to temprate,
conifers vegetation,in the presence of acid humus and
low base status.
⢠Group of zonal soils designated as E-horizon.
⢠The process of podzol soil development is called
podzolization.
24. BROWN FOREST SOILS
⢠The soils developed on sedimentry and
metamorphic rocks and alluvium,under submit to
humid climatic environment and deciduous or
mixed vegetation,are non- calcic Brown and brown
forest soils.
27. Peaty and marshy soils
⢠The name peaty and marshy is given to the soils
that have developed into he low-lying coastal
marshy land or to soils confined to depressions
caused by dried lakes in the alluvial and coastal
plain areas,formerly occupied by mangrove
swamps.
29. CAT-CLAY OR ACID SULPHATE SOILS
⢠In India such saline peat soils are termed as kari in
the kerela state.
⢠These soils are highly problematic and very poor
for plant growth.it is because of the presence of
pyrite ,which on oxidation,produce sulphuric acid.