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| One of the bird of the desert bird of paradise, a legume. Most legumes have characteristic flowers and leaves. |
Q. Do nitrogen fixers like trumpet vines and locust trees
provide significant nitrogen to nearby plants?
For example the Bermuda lawn surrounding the locust or the iris and
daffodils in a flower bed anchored by a trumpet vine.
A. No they don’t produce enough for our high expectations
in landscapes and gardens. Nitrogen fixers (such as legumes, there are others) supply enough to help
make sure they can reproduce and make seed. The objectives (if I can put it in
human terms) of plants and humans are different. Plants want to survive, reproduce
and out-compete with other plants for their niche. In nitrogen poor soils
nitrogen fixers, like legumes, take nitrogen from the air and supplement what
they can’t get from the ground. In nitrogen poor soils, legumes are fantastic
competitors. In nitrogen rich soils they are not.
in landscapes and gardens. Nitrogen fixers (such as legumes, there are others) supply enough to help
make sure they can reproduce and make seed. The objectives (if I can put it in
human terms) of plants and humans are different. Plants want to survive, reproduce
and out-compete with other plants for their niche. In nitrogen poor soils
nitrogen fixers, like legumes, take nitrogen from the air and supplement what
they can’t get from the ground. In nitrogen poor soils, legumes are fantastic
competitors. In nitrogen rich soils they are not.
Typical legume flower leaf and pod
The
expectations of humans for the plants they care for are far greater than plant
objectives. We want beauty and lushness from landscape plants and we want a
good production of food from our legume crops.
expectations of humans for the plants they care for are far greater than plant
objectives. We want beauty and lushness from landscape plants and we want a
good production of food from our legume crops.
The
nitrogen needed to meet human expectations is far greater than the nitrogen
needed to meet plant objectives. So for this reason, we need to fertilize
nitrogen fixing plants with nitrogen to meet our objectives. The basic rule of
thumb I use is the question, “So I want my plants to meet what they consider to
be adequate (reproduction and beat out the competition) or do I want them to do
more than that?”
nitrogen needed to meet human expectations is far greater than the nitrogen
needed to meet plant objectives. So for this reason, we need to fertilize
nitrogen fixing plants with nitrogen to meet our objectives. The basic rule of
thumb I use is the question, “So I want my plants to meet what they consider to
be adequate (reproduction and beat out the competition) or do I want them to do
more than that?”
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| Snow pea flowers and leaves are good examples of what many legumes resemble |
Most
people want these plants to do far more than successfully reproduce. Some
people are purists and they want that “native look” or for philosophical
reasons they prefer the plant produce what it can they are happy living in the “nitrogen cycle”. Nothing wrong with that and it meets their
expectations. If you want lushness or greater production, then add extra nitrogen.
people want these plants to do far more than successfully reproduce. Some
people are purists and they want that “native look” or for philosophical
reasons they prefer the plant produce what it can they are happy living in the “nitrogen cycle”. Nothing wrong with that and it meets their
expectations. If you want lushness or greater production, then add extra nitrogen.
The
general rule of thumb you can follow is that many nitrogen fixing plants
receive only about 25%, at best, of the nitrogen they need to meet our
expectations. However you can treat legumes just like any other
plant and feed them extra nitrogen. Plants can be lazy. If you give them all this nitrogen, they may produce little to no nodules
on the roots (the nodules contain the nitrogen fixing bacteria). Hey, its alot easier to take available nitrogen than it is to build these homes on their roots for these symbiotic bacteria that take nitrogen from the air.
general rule of thumb you can follow is that many nitrogen fixing plants
receive only about 25%, at best, of the nitrogen they need to meet our
expectations. However you can treat legumes just like any other
plant and feed them extra nitrogen. Plants can be lazy. If you give them all this nitrogen, they may produce little to no nodules
on the roots (the nodules contain the nitrogen fixing bacteria). Hey, its alot easier to take available nitrogen than it is to build these homes on their roots for these symbiotic bacteria that take nitrogen from the air.
root nodules of legume can resemble root knot nematode infestation
We are lucky in that nitrogen
fixation by legumes is far more efficient in our alkaline soils of the desert than in acid soils of high rainfall areas. So
to answer your question with a short winded response, no, they will not produce
enough nitrogen for surrounding plants if your landscape expectations are high. If you are a eco-purist, then maybe they will.
fixation by legumes is far more efficient in our alkaline soils of the desert than in acid soils of high rainfall areas. So
to answer your question with a short winded response, no, they will not produce
enough nitrogen for surrounding plants if your landscape expectations are high. If you are a eco-purist, then maybe they will.