Download The Nitrogen Cycle

The Nitrogen Cycle
Plants use nitrates
from the soil to
make proteins.
 Nitrates get into
the soil from
decayed faeces,
animals and plants.
 This is why manure
helps plants grow.

When dead animals
or plants, or faeces
are decayed by
putrefying bacteria,
ammonium
compounds are
released.
 These contain a lot
of Nitrogen.

Ammonium
compounds are
converted to
nitrates by
nitrifying bacteria.
 Nitrates can be
easily absorbed by
plants that use them
to make proteins.

 The
cycle where
nitrogen is
moved from the
soil, into
organisms and
back again is
called the
Nitrogen Cycle.
The Nitrogen Cycle
4. Nitrifying bacteria
convert ammonium compounds
into NITRATES
1. Plants absorb
nitrogen in the form of
NITRATES
Nitrates in
the soil
Waste and
dead animals
Plants
Animals
3. Microbes break down
waste products and dead
animals and plants to form
AMMONIUM COMPOUNDS
2. Plants are then
eaten by animals –
the nitrogen
becomes PROTEIN