“Nitrogen fixation is a process by which nitrogen (N2) in the atmosphere is converted into ammonia (NH3). Atmospheric nitrogen or molecular nitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds. Fixation processes free up the nitrogen atoms from their diatomic form (N2) to be used in other ways.” — Wikipedia.org
For gardeners and farmers, nitrogen fixation is an important process as it is one way of improving soil. This is done by using crop rotation to plant nitrogen fixing plants, like legumes in rotation with nitrogen-heavy feeders such as corn. As the Wikipedia article mentions, Nitrogen is a fairly inactive gas. Even though is exits in large quantities in the atmosphere, it is very difficult to get it back into the soil where plants can make use of it.
One legume often used to crop rotation is the soybean. Growing up in farm land Ohio, soybeans, corn, wheat and timothy hay and alfalfa were common crops rotated through the fields. Alfalfa is another good nitrogen fixing crop, along with the soybeans, Using nitrogen fixing plants can help to reduce the amount of supplemental nutrients and fertilizer that might need to be added to a garden or farm field.
Alfalfa and clover are commonly used as nitrogen fixing “cover crops” which are grown not be harvested themselves, but rather to be turned into the soil during Spring planting to return the nitrogen they have gathered to the soil.
More information on stoma:
- Nitrogen Fixation at Wikipedia
- Nitrogen Fixation Diagrams at Google Image Search
- Nitrogen Fixation at Nature.com
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This Garden Vocabulary series seeks to introduce and explain to you — and in many cases, myself — words and terms associated with gardening. Please let me know if there are any terms you would like me to explore. You can leave your ideas in the comments section and we can learn together!