The
Nitrogen
Cycle
By: Reynaldo Thomas


Nitrogen is an essential element needed for
protein formation.
The air around us contain approximately 79% of
nitrogen
(format of gas).


Most living things
can not use
nitrogen in this
format.
Nitrogen gas is
Inert.

Humans taking nitrogen in the format of proteins
from plants or other animal.
Return of nitrogen to Soil
Urea



When animal break down proteins, urea is
produce as a
waste product.
Urea is excreted
as urine.
Bacteria convert
urea into nitrate.
Nitrogen Gas


Nitrogen fixing bacteria in the roots of some
plants converts nitrogen gas into ammonium
compound.
Nitrifying bacteria
then convert
ammonium into
nitrite and then
nitrate.
Plants/Animal Matter
 When plants and animals die they are
decomposed by bacteria, forming ammonium
compounds.

Nitrifying bacteria
then convert
ammonium to
nitrites and then
into nitrates.
Lighting oxides of Nitrogen
 During thunder storms lighting convert nitrogen
gas into nitrates.

The rain will then
wash the nitrogen
compounds into
the soil.
Artificial Fertilizer
 The addition of man made fertilizer will add
nitrates to the soil.

Hence increasing
the soil fertility.
Denitrifying Bacteria
 This type of bacteria undo the work done by
others by converting nitrates back to nitrogen
gas.