Although men and women have been growing crops for thousands of years, they have not always had enough to eat.
Although
men
and
women
have
been
growing
crops
for
thousands
of
years
,
they
have
not
always
had
enough
to
eat
.
Even today, many people in the world go hungry, and even die of hunger.
Even
today
,
many
people
in
the
world
go
hungry
,
and
even
die
of
hunger
.
If we are to grow enough for everybody, we have to grow more crops and better crops.
If
we
are
to
grow
enough
for
everybody
,
we
have
to
grow
more
crops
and
better
crops
.
Plants need the right food in order to grow.
Plants
need
the
right
food
in
order
to
grow
.
In particular, they need three chemical substances in the soil: nitrogen, phosphorus and potassium.
In
particular
,
they
need
three
chemical
substances
in
the
soil
:
nitrogen
,
phosphorus
and
potassium
.
They also need smaller amounts of other chemical substances like calcium.
They
also
need
smaller
amounts
of
other
chemical
substances
like
calcium
.
If there is too little of any of these substances in the soil, plants can't grow well.
If
there
is
too
little
of
any
of
these
substances
in
the
soil
,
plants
ca
n't
grow
well
.
When a plant grows, it takes up these basic substances from the soil and builds them into itself.
When
a
plant
grows
,
it
takes
up
these
basic
substances
from
the
soil
and
builds
them
into
itself
.
If we remove the plant from the soil and use it for food, we are taking some of these substances away, and this means that future plants will find less of them in the soil.
If
we
remove
the
plant
from
the
soil
and
use
it
for
food
,
we
are
taking
some
of
these
substances
away
,
and
this
means
that
future
plants
will
find
less
of
them
in
the
soil
.
In time, the soil would become too poor for plants to grow in it at all.
In
time
,
the
soil
would
become
too
poor
for
plants
to
grow
in
it
at
all
.
To prevent this we must put basic substances back.
To
prevent
this
we
must
put
basic
substances
back
.
One way of doing this is putting manure on the soil.
One
way
of
doing
this
is
putting
manure
on
the
soil
.
This contains the remains of plants that have been eaten, and, if we add it to the soil, we are returning some of the basic substances.
This
contains
the
remains
of
plants
that
have
been
eaten
,
and
,
if
we
add
it
to
the
soil
,
we
are
returning
some
of
the
basic
substances
.
In Europe and in prefix = st1 /Japan, manure from animals has for long been used in this way.
In
Europe
and
in
prefix
=
st1
/Japan
,
manure
from
animals
has
for
long
been
used
in
this
way
.
Unfortunately much of the animal waste inIndiais used as fuel because there is not enough wood to burn.
Unfortunately
much
of
the
animal
waste
inIndiais
used
as
fuel
because
there
is
not
enough
wood
to
burn
.
This means there is less manure for the crops.
This
means
there
is
less
manure
for
the
crops
.
Even when we use manure, we cannot put back into the soil more of the basic substances than have been taken out.
Even
when
we
use
manure
,
we
can
not
put
back
into
the
soil
more
of
the
basic
substances
than
have
been
taken
out
.
Often the soil does not have enough of them in the first place, and so we must provide extra supplies.
Often
the
soil
does
not
have
enough
of
them
in
the
first
place
,
and
so
we
must
provide
extra
supplies
.
We can use chemical fertilizers.
We
can
use
chemical
fertilizers
.
Experiments in Indiahave shown that, if we use a fertilizer containing a mixture of nitrogen and phosphorus, we get half as much rice again from the crops on any one piece of land.
Experiments
in
Indiahave
shown
that
,
if
we
use
a
fertilizer
containing
a
mixture
of
nitrogen
and
phosphorus
,
we
get
half
as
much
rice
again
from
the
crops
on
any
one
piece
of
land
.
Although men and women have been growing crops for thousands of years, they have not always had enough to eat. Even today, many people in the world go hungry, and even die of hunger. If we are to grow enough for everybody, we have to grow more crops and better crops.  Plants need the right food in order to grow. In particular, they need three chemical substances in the soil: nitrogen, phosphorus and potassium. They also need smaller amounts of other chemical substances like calcium. If there is too little of any of these substances in the soil, plants can't grow well.  When a plant grows, it takes up these basic substances from the soil and builds them into itself. If we remove the plant from the soil and use it for food, we are taking some of these substances away, and this means that future plants will find less of them in the soil. In time, the soil would become too poor for plants to grow in it at all.  To prevent this we must put basic substances back. One way of doing this is putting manure on the soil. This contains the remains of plants that have been eaten, and, if we add it to the soil, we are returning some of the basic substances. In Europe and in prefix = st1 /Japan, manure from animals has for long been used in this way. Unfortunately much of the animal waste inIndiais used as fuel because there is not enough wood to burn. This means there is less manure for the crops.  Even when we use manure, we cannot put back into the soil more of the basic substances than have been taken out. Often the soil does not have enough of them in the first place, and so we must provide extra supplies. We can use chemical fertilizers. Experiments in Indiahave shown that, if we use a fertilizer containing a mixture of nitrogen and phosphorus, we get half as much rice again from the crops on any one piece of land.