Legumes
Alfalfa is the most common legume planted for hay. It is
important for a sustainable field because it enriches the soil
with nitrogen.
A field with a healthy legume population does not require
much nitrogen fertilizer. Nitrogen is a key element for building
protein structures in living cells.
Legumes have nitrogen fixing bacteria in their roots that take
nitrogen from the air and infuse it into the soil. A legume is
an example of an organism that has a symbiotic relationship
with bacteria. Bacteria provide the plant with nitrogen while
the bacteria get carbohydrates from the plant. Soybeans,
peas, clover and peanuts are also legume plants. They are
sometimes referred to as green manure because they fertilize
the soil with nitrogen.
Can you see the
nodules on the roots
of this plant? That is
where the nitrogen
fixing bacteria live.
Nitrogen fixing bacteria
and legume plants have a
symbiotic relationship. Answer
the question below about this
relationship.
What two organisms are involved in this
relationship?
_____________________________________________
_____________________________________________
Would you think that this relationship is
benefiting both organisms? __________________
What are the bacteria getting out of the
relationship? ________________________________
What is the legume getting from the
relationship? ________________________________
Colorado Ag in the Classroom
7
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