L7 : Sandy; Clayey; Loamy Soil - Soil, Science, Class 7 Video Lecture

hello friends this video on soil part 7
is brought to you by exam viacom no more
fear from exam so let us start with the
properties of sandy soil sandy soil the
word sandy comes from sand and what what
could you think of when you hear when
you get this term sand sand would remind
you of a desert you would have seen sand
there right it's a fact you can act if
you take sand in your hand you can
actually feel the presence of some
particles in it so you can feel the
coarse texture of sand so let's see what
the sandy soil it is well aerated now
when we are talking about sandy soil we
are talking about the soil which has
more number of bigger particles so
obviously this side this soil is not
going to be very you know very powdery
it is going to be something where you
can feel the presence of particles
because the particles are big enough and
that is what happens when you take sand
in your hand you can actually feel the
presence of particles it is not very
powdery very smooth so this is let us
say the example of an agent of sandy
soil since night sandy zone these are
the particles which are big enough and
since the particles are big enough
therefore the spaces between the
particles are also big enough now what
do we do with these pieces so these
pieces can hold air
so air will be present in these spaces
so that is why this type of soil is well
aerated so sufficient amount of air is
present in this soil in these kind of
soils that is inside the soil do not
retain water however they are not very
good at holding water
why do you know why that's because now
in this case since the particle size are
big most of the particles are big in
size
therefore these particles do not fit
very closely together you see a lot of
open spaces in between the sense they
are not of open spaces when you
you put water on this type of soil what
happens water will quickly pass down
through these empty spaces so basically
what water will drain down through this
type of soil so the soil may not be able
to hold any water because the spaces
between the particles are big very big
so water drain quickly through these
phases between them sand particles and
therefore since it cannot hold the water
so it does not remain wet because there
is no water inside even if you put water
understand it is very quickly drain
through it and it will reach underground
it will go very deep right because we
already saw how to soil the other side
so when they put water on the soil it
will very quickly go get deeper deeper
deeper and it will finally reach the
layer of rocks
that's all that can happen so basically
the soil will therefore remain dry
because the soil is not containing any
type of water so it is very poor at
retaining water on holding water so this
makes this soil quite dry and that is
why they are light in weight because the
weight is only of the particles there is
no additional thing being present there
now there is no water have you ever
observed that if you have a dress when
you make it wet and you try to wait it
becomes alien well because now it is the
weight of the dress plus the weight of
the water so therefore it becomes heavy
similarly in case of soil also if a wet
soil a sample of wet soil will behavior
than a sample of dry soil so these sandy
soils since they do not hold water they
do not retain water therefore they are
light in weight
however sandy soil is the worst type of
soil for plant growth do you know why
because most of the plants need good
amount of water for their growth and
development I am talking about most of
the plants however there could be
certain exceptions so many plants need
lot of water now this type of soil if
you plant if you plant a tree
sandy soil the tree will need a lot of
water but this soil even if you you are
applying water to the soil the soil is
not able to retain the water therefore
the water is actually draining deep down
therefore water is not made available to
the plants because plants are in touch
with the upper layers of the soil the a
horizon and B horizon that's it but the
water is actually not being retained in
the EOB horizon water is going deep
inside it
therefore this soil being very dry do
not allow roots of the plants to develop
properly the roots are not able to get
enough water the roots are not able to
establish their connections with these
dried sandy soils so this is the reason
that if deserts you really do not see a
lot of trees that's because desert has
all these are designed all around and
sand again being sandy soil they do not
retain water they are not very suitable
for growth of tons the next type of
soils the clay soil so it is just going
to be just the opposite of sandy soil so
we will now look at the properties of
clay soil which is going to be just the
reverse of sandy soil so in this case
there is very little water now what
happens in case of clay soil not here as
I have mentioned before that this kind
of soil is made up of very tiny
particles so fine particles are present
in this type of soil so as a result if
you look at it you see these are watch
tiny particles so the spaces in between
is very small but at the same time
therefore the air is holding the spaces
so you see only very tiny spaces are
there here and there so in these tiny
spaces only little amount of air can be
present so therefore they hold quite
less air
when compared to the sandy soil also
here in this case the particles are
packed very tightly together with little
or no space for air so that is why this
is also the densest soil because you can
see the density is very high so it is
that then siehst then siehst soil and
also heavy s soil now why is it heaviest
that's because it can retain a lot of
water now how does it read rain so much
of water how can it hold so much of
water that is because due to its high
density it is very difficult for water
droplets our air to penetrate into it so
they do not drain through it like how it
was an ease of sandy soil in sandy soil
the gaps are in a quite big so water
would easily flow through the gaps so
the water would drain very quickly but
in this case that is not the case the
gaps are like very tiny so if water
enters into that gap so let's suppose if
water enters into this gap so it kind of
get stuck it cannot move beyond because
again you do not see sensitive gap
anywhere so that is why in each and
every gap there is some water which gets
your kind of lot so that's how we can
say that this soil retains a lot of
water so within the soil you actually
see a lot of water
now since the soil contains so much of
water therefore it also becomes a B
because now it is not only the weight of
the soil but also the way additional bit
of water that is it is densest as well
as heaviest it is very heavy as I
mentioned just now now there are many
plants which grow on clay soils
specifically plants which need a lot of
water now as I mentioned before also
that different plants have different
requirements for their growth some
plants need less water some plants need
more water
so those bands which need more water
they grow better on plain soil so
specially phones and some of the plants
they generally grow on clay soil and
this type of soil is also used for
making pottery
so you would have seen the urban ports
and vessels which I prepared using soil
so sandy soil will not be a good choice
because with them they do not you know
retain water but this soil since it
retains water so you can actually you
it's like you can give it a shape and
them that's how it can be quite tough as
well so it is used for all these kept
making oil kind of pots the third type
of soil that is loamy soil and this soil
holds the right amount of water now what
do we mean by right about the water now
till now we saw that sandy soil does not
hold water at all clay soil holds a lot
of one so domain soil is like kind of
intermediate between the two so it holds
more water than sandy soil but less than
that of clay soil so it is like the
perfect amount of water is being hold by
loamy soil so what does this soil
actually this soil consists of equal
number of big particles and small
particles so as you can see in the
picture both big and small particles are
present him in fact we can see that this
soil is the perfect soil for growth of
plants because it contains the exact
amount of water that is needed by the
plants it also contains the right amount
of nutrients it also contains yuma's
which improves the you know fertility of
the soil
so basically lunar soil contains sand it
also contains claim it also contains
humors
it also contains silt so silt is
something new so we will discuss inside
away the sand which was present in the
sandy soil clay which was present in
clay you saw it so these two things we
have already seen you must this is
nothing but the decaying plant that
animal remains so it improves the
fertility of
so it basically improves the quality of
the soil for better growth of crops and
what about silt so cell is also a kind
of particle where the it is like
generally a deposit which is more mostly
seen in the river beds and the size of
the particles in sill is between sand
and clay like it is of Sam the particles
are like quite big it gives of play the
particles already tiny so sill is
somewhere in between the size of
particles of a sand and that clay so it
is generally a person soil or as a
suspension mixed with water in water
body especially river so mostly it is
seen in the riverbeds so due to the
appropriate size of the particle of the
sill it is also beneficial because then
as you are seeing that the size of the
particle decides the property of that
particular type of soil now all these
things together compose the loamy soil
now however the specific composition may
vary like how its and how much they how
itself so that composition might be
balanced but if some amount of compost
is added to it then it becomes the
perfect thing for growth of most of the
plants so loamy soil is something which
is in demand by most of the plants
because generally all plants can grow
within loamy soil because here it has
got a booth it has got the advantages of
goods and this way as well as playing
soil
so that's about loamy soil thank you
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