Soil Flashcards
(50 cards)
what are the factors affecting soil fertility?
moisture
nutrients- phosphorous nitrogen potassium etc.
depth of soil
organic matter or humus.
what is in-situ soil?
soil which is formed at original loc. by breaking of parent rock.
also called residual/sedimentary soil.
have well defined soil profile.
e.g. black, red, laterite, sandy desert soil.
what is ex-situ soil?
soil which is formed by sediments transported by wind, water etc.
also called transported soil
do not have well defined soil profile.
e.g. alluvial soil.
brief note on alluvial soil.
transported, loamy soil
covers 40% land mass.
also called riverine soil.
found in entire northern plains, deltas of mahanadi godavari krishna and kaveri
what is loam?
a mixture of clay silt and sand.
what is Khadar?
newer deposits of soil closer to the river banks.
has finer particles of silt and clay and is light in color.
is more fertile as new deposits are added every year.
it lies below flood levels of river.
what is Bhangar?
older alluvial soil which is not as fertile as khadar
occupies maximum portion of northern plains
is above flood levels of river
has lime nodules called kankar
where is inland alluvium found?
Indus, ganga, Brahmaputra plains,
Bangladesh, Assam, Punjab, Haryana, UP,, Bihar
Gujrat, few patches of Rajasthan.
where is deltaic alluvium found?
deltas of ganga-Brahmaputra, mahanadi, godavari, krishna, kaveri
where is coastal alluvium found?
tidal origin
coastal strips of India, plains of Gujrat.
color and texture of alluvial soil
colour- light grey to deep black depending on depth, texture and time of maturity.
texture- upper reaches are dry coarse porous
lower plains- small/fine particles, uniform, compact.
minerals found in alluvial soil
rich in - iron, magnesia, potash, lime
lack- phosphorous nitrogen humus.
only ganga plains soil has humus.
soil in drier regions is basic in nature.
what are the crops grown in alluvial soil.
rice, wheat, sugarcane, oilseeds, jute(lower G-B plains), cotton, tobacco
brief note on black soil.
residual, clayey soil
formed by denudation of volcanic rocks
found along the deccan lava tract - i.e. Maharashtra, Gujrat, Andhra Karnataka T.N.
also called black cotton soil or regur soil.
color and texture of black soil
colour- black made out of igneous rocks
texture- fine, clayey, highly water retentive,
how is black soil self ploughing?
due to high water retentivity, it absorbs moisture in monsoon and expands.
in dry season it shrinks and cracks up
these cracks allow entry of oxygen and water into the soil. cracks get filled up in the rains.
minerals found in black soil.
high- iron, magnesia, lime
low- nitrogen, phosphorous, humus.
crops grown in black soil
cotton, wheat, jowar, linseed, sugarcane, tobacco
why is black soil good for dry farming?
water is always present in subsoil of black soil.
brief note on red soil.
second largest soil group after alluvial soil
made from denudation of old crystalline rocks by rainfall.
found in the peninsular region of india surround in the black soil region.
bundelkhand (n)
Rajmahal hills(e)
kutch(w)
Tamil nadu(s)
color and texture of red soil.
residual loamy soil
red color due to Fe2O3.
porous loose aerated shallow
what are the minerals in red soil
poor- N, P, Na, humus, soluble salts.
how can farming be done in red soil.
red soil is not very fertile, but it responds well to fertilizers.
it needs irrigation.
what kind of crops are grown in red soil?
vegetables, ragi, tobacco,
higher land- coarse soil- potato ground nut
lower land- clayey soil- sugarcane.
