Nitrogen-fixing Abilty
Many legumes (alfalfa, clover, peas, beans, lentils, soybeans, peanuts and others) contain symbiotic bacteria called Rhizobia within nodules of their root systems. These bacteria have the special ability of fixing nitrogen from atmospheric, molecular nitrogen (N2) into ammonia (NH3). The chemical reaction is:
- N2 + 8 H+ + 8 eā ā 2 NH3 + H2
Ammonia is then converted to another form, ammonium (NH4+), usable by (some) plants by the following reaction:
- NH3 + H+ ā NH4+
This arrangement means that the root nodules are sources of nitrogen for legumes, making them relatively rich in plant proteins.
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