The Nitrogen Cycle- Agriculture

Ammonification

Assimilation

Nitrification

NO

NO

NH

NH

Agriculture & Nitrogen Cycle

• Part of decaying process
• Plant or animal dies and decomposers like fungi and bacteria turn nitrogen back into ammonium.

Ammonium (NH )

• Organisms can not use nitrogen in this gaseous form.
• A process called nitrogen fixation converts nitrogen into a form living things can use.

About 78% of the atmosphere is nitrogen gas.

Nitrogen (N )

• Form that plants can use.

• Absorb nitrates from soil into roots.

Nitrate Ion (No )

Ammonia is toxic to most living things.

Nitrogen-fixing bacteria convert the nitrogen gas into ammonia as a waste product of nitrogen fixation.

Ammonia (NH )

• Wastewater Management

• Livestock

Nitrogen entering Watershed:

• Fertilizer runoff

Denitrification

• Not all nitrogen in soil is used by plants.
• Denitrifying bacteria take excess nitrogen and convert it back into nitrogen gas during this process.

• Human activity has altered cycle, adding extra nitrogen into the soil with fertilizer and other activities that result in more nitrogen entering the atmosphere.

Nitrogen dioxide (NO ) also known as a nitrite.

Nitrifying Bacteria

Two step process:

1) Bacteria convert ammonia into nitrite (NO2-) 2) Bacteria convert nitrite into nitrate (NO3-)