What makes fertilizer so successful
in helping plants grow?
Nitrogen
It encourages growth of the
vegetative parts of plants:
• stems
• leaves
• roots
Why is nitrogen so important
to living components?
•It makes up proteins, DNA and
other compounds.
•Without it, life wouldn’t exist
The
Nitrogen
Cycle
http://www.vtaide.com/png/nitrogenCycle.htm
Explain the process of nitrogen fixation.
Nitrogen gas (N2)
must be “fixed” (attached)
to make other compounds such as
ammonium (NH3+)
Explain the role of nitrogen-fixing bacteria.
• Bacteria that live in nodules on plant
roots or in the soil which “fix” (attach)
nitrogen to hydrogen so that plants can
use it for growth
Explain how nitrogen enters the food chain.
1. Nitrogen must first be fixed in the soil.
2. Then plants will absorb it through their roots and use it
to make their tissues.
3. Primary consumers eat the plant and the nitrogen is
passed on and becomes a part of the animal.
4. Producers, consumers, and their wastes are
decomposed to release the nutrients to the environment
once more.
Explain how nitrogen can re-enter the food chain
without nitrogen returning to the atmosphere.
• The wastes of organisms and dead material are broken
down by decomposers.
• This produces ammonia which is converted to nitrate by
nitrifying bacteria.
• This nitrate is taken up by the plant to use again.
Explain the roles of nitrifying bacteria and
denitrifying bacteria.
1.
Nitrifying bacteria: convert ammonium (NH3+) into nitrites (NO2-)
and then nitrates (NO3-) which can be used by plants = Nitrification
2.
Denitrifying bacteria: convert nitrates (NO3-) in the soil into
nitrogen gas (N2) which is released to the atmosphere and oxygen
(O2) which is available to the nitrifying bacteria = Denitrification