----- Original Message -----
From:
t*@ca.rr.com
Moira, if you have time I would appreciate it if
you would send me the explanation you sent Diane Whitehead.
Your comments in the past have been very helpful
to me.
Hi Janet
I am sorry I had intended to send it to the whole
list, but did not hit the right buttons.
Here is a copy
Dianewrote
I read recently that nitrogen-fixing plants only manage to fix
enough for
> themselves and don't share with neighbouring
plants. I can't remember
> where I read
it.
Diane
As long as the roots with the nodules are healthy and
active the nitrogen
they fix does not spread into the surrounding soil,
but if the root or even
just the nodule, should die it will break down and
release some nitrogen and
when the whole plant finally dies all the
nitrogen it has fixed will go to
top up the supply in the soil.
In
many soils the free-living nitrogen fixing bacteria are also active. They
are commonly associated with plant roots though not forming nodules. The
plants seem to deliberately attract them by providing gifts of energy-rich
sugar solution which aid the bacteria to do the nitrogen fixing, so that a
"mutual benefit society" results.
The problem with Med. plants
however is that for a good bit of the year the
soils are very dry and
bacterial activity is probably much reduced, so that
plants my look yellow
and unhappy for a while, but recover when the next
shower of rain
starts the soil organisms into activity once more.
Genuine Med. species
in fact quite often tend to aestivate (go into summer
dormancy) just as
plants from cold latitudes hibernate through winter. At
this time the
reduced activity may make them look pale and unhappy, but come
rain and
they will rapidly recover and turn green once more.
Moira
PS my advce to Charl to add compost to his soil
was mainly to create a better climate for bacterial
activity.
