The Nitrogen Cycle

How are the different sources of N made available to the plant or, on the other hand, lost from the root zone to air or water?

Answer: The Nitrogen Cycle

The N cycle involves many processess that make the N in manure, fertilizer, soil, and killed sod available to plants. Plant available N can also be lost from the rootzone to the atmosphere and groundwater and/or taken up by competing organisms (e.g. weeds, soil microbes, etc.).

The major conversion processes at play in the crop and soil N cycle are below.

• N fixation.
• Mineralization.
• Nitrification.
• Denitrification.
• Ammonia volatilization.
• Immobilization.

Although not conversion processes, the following are key components of the N Cycle.

• Nitrate leaching.
• Crop uptake.

Step through the interactive N cycle diagram to see how each N source can shift to other forms of N by the conversion processes, above. What does it mean for crop production (i.e. N uptake by plants)? For losses from the root zone to water and air?

For a printable, fact sheet version of the N cycle: N Cycle Fact Sheet.

To read more on this subject: Nitrogen Guidelines for Field Crops in New York (section 2).

Continue on to see how the basics of the N cycle are used to determine crop N requirements.