In article .com, wrote:
[rec.gardens restored]
[ Okay. I guess it's no more dangerous than rec.food.cooking. ]

Phred wrote:
In article .com,
wrote:
[snip]
I do have sweet clover and alfalfa growing wild in my garden, and I
encourage them because I need all the nitrogen and all the plants with
flowers I can get, but according to
http://www.fao.org/Wairdocs/ILRI/x5546E/x5546e05.htm there's a
particular species of bacteria (Rhizobium meliloti) that's symbiotic
with those plants. I suspect that it won't be symbiotic with the other
plants I mentioned (Caesalpinia, Calliandra, Dalea). Can anyone tell
me for sure?

No. :-)

I'm beginning to figure that out.

You don't say what species you will be using. It's quite
possible that some species in a genus will be exacting in
their requirements while others may be promiscuous.

With _Calliandra calothyrsus_, here's a quote from
http://www.fao.org/ag/agp/agpc/doc/Publicat/Gutt-shel/x5556e09.htm
[ TinyURL: http://tinyurl.com/zj4wy ]
which also has lots of other good stuff about this species:
quoting
It is commonly stated that inoculation with Rhizobium is not
necessary (Zhou and Han 1984) but use of an appropriate strain
is advised when introducing the plant to new areas.
/quoting
....

As it happens, it's /Calliandra eriophylla/.

Bit frustrating looking up that one isn't it.
Did you manage to find:
http://www.rbgkew.org.uk/herbarium/legumes/beanbag49/nodulation.html

It says Rhizobia have been found on the roots of that species, based
on this reference book: Brewbaker, J.L. 1987. Significant nitrogen
fixing trees in agroforestry systems. Agroforestry: realities,
possibilities and potentials, pp.31-45. Martinus Nijhoff, Dordrecht,
Netherlands.

The page has a pretty comprehensive list of both known and unknown
responses in a wide range of legumes, and some related info on RNB.
It seems to be an extension of a previous paper by Allen and Allen
1981; but in spite of giving a large list of references, the buggers
don't elaborate on that one! At a guess it could refer to...
Allen O.N., Allen E.K. (1981) The Leguminosae: a Source Book of
Characteristics, Uses and Nodulation. MacMillan: London.

Thanks to all who replied. Here's an example of what I get when I look
for a particular species, /Caesalpinia gilliesii/.

"Nitrogen fixation None"
http://plants.nrcs.usda.gov/cgi_bin/plant_attribute.cgi?symbol=CAGI

That may be the result of actual research. (Then again, maybe not.

"No fertilizing is required, these plants fix nitrogen in the soil."
http://www.monrovia.com/PlantInf.nsf...87e69/f018b4fc
37a9469488256f250065bf53!OpenDocument&Click=88256 8470064D136.77a6cc4887b5c2ab88
256f0e007d62a5/$Body/0.2512

That is most probably due to uncritical misguided faith in the idea
that "Legumes fix nitrogen from the air." It ain't necessarily so.

But maybe I'll find a consensus on some other species. Anyway, I think
the answer to my questions is, "If it looks like it's short of
nitrogen, give it some."

What a good idea! ;-) But, be aware that there's a fair body of
research showing even legumes with a good reputation for N fixation
may become parasitic on soil N if there's enough of it around. I
assume they will revert to fixing the stuff if the external supply
runs out; but there's at least a potential problem if the effective
RNB population has been seriously reduced or even died out due to
competition with ineffective strains in the presence of lots of N.

Cheers, Phred.

--
LID