Transcript Nitrogen Cycle Topic 1016 D Matt Jakubik

Nitrogen Cycle
Topic 1016 D
Matt Jakubik
Facts
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Earth’s Atmosphere is almost 80 % nitrogen
(N2)
Most nitrogen is added to soil by rain or dust
particles
Some plants have bacteria help with nitrogen
uptake
Others have aerial roots that can absorb from
the air
Processes
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Nitrogen Fixation
Mineralization
Nitrification
Immobilization
Denitrification
Nitrogen Fixation
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N2 taken from the atmosphere to the plant
Nodules on legumes
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Bacteria-Rhizobium
Ammonia applied to soil
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Soil picks up H+
http://biology.kenyon.edu/courses/biol272/agriculture/nodulation2.jpg
Mineralization
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Also called ammonification
99 % of soil nitrogen is organic nitrogen in
organic matter
1-2% is mineralized each year
Nitrogen from manure
Nitrification
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Oxidation of ammonium (NH4+) to nitrite
(NO2-) to nitrate (NO3-)
Two step process
Process will not take place in saturated soils
Immobilization
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Conversion of Inorganic (minerals) Nitrogen to
organic nitrogen
Stable in the soil
Denitrification
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Reduction of nitrate or nitrite by microbial
activity
Gaseous process
Escapes the soil
Prevents nitrogen in groundwater as
overabundance occurs
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