"China" wrote in
:

G'day Ivan,

snip green manure idea

Thanks China, I did consider growing wheat - I tend to get plenty left over
from the wild bird feeder (fussy bloody parrots but came to the
conclusion that green manuring is best left until after I get some other
organic matter into the ground. I can obtain and spread up to approximately
10m^3 of grass clippings per week - I just can't see a green manure crop of
any type providing this amount of organic material.

Another reason that I am tending towards grass clippings is that these are
provided by a professional lawn mower. My assumption is that people who can
afford a professional lawn mower and care enough about their lawn to do so
probably also fertilise and water their lawn regularly. In theory,
therefore, I am going to get not just the organic matter but the trace
elements and "extra" primary elements that other peoples fertiliser
provides. Maybe this isn't "strictly organic" but it's close enough for me
- growing my own green stuff will only recycle whatever is already in
the sand.

As far as green manure is concerned though I just recently read about the
value of sunflowers. I know from experience that sunflowers grow just as
quickly as wheat (if not more so). The book I was reading said that
sunflowers provide a much greater bulk than most other green manure crops
if they are "harvested" at about 1m high. They need to be harvested early
so that the stems are moist enough, thin enough and have a high enough
nitrogen content to compost/decompose fairly quickly. The bad thing, for
me, about sunflowers is that I would really need a mulching machine to take
full advantage and I don't have one yet.

I was reading just yesterday about azotobacter which, as you probably know,
are nitrogen fixing bacteria that are not symbiotic. The relevence of this
is that the azotobacter basically need just organic matter and oxygen and
then "fix" atmospheric nitrogen. Obviously the more of these little
critters the better and by using the grass clippings and chook poo I
believe I will get more organic matter into the ground more quickly than by
using a green manure. The rotary hoe used every 4 weeks or so should keep
the oxygen level pretty decent. I also expect and hope that by providing
the ground with this material (ready to decompose and partially decomposed)
I will encourage the worms more quickly. Because the chook poo is
relatively dry I don't expect any problems from it being too "hot".

If I understood correctly what I was reading (which is always a doubtful
proposition the acidity provided by the decomposing grass will speed the
process of transforming some of the non-bio-available nutrients into bio-
available. On the down side, of course, the azotobacter, worms, most fungii
and especially my vegetables don't like acid soil and so lime will be
required probably in the form of dolomite (since the magnesium is needed by
the azotobacter and the calcium will address the problem of acidity).

What amazes me is just how complex the soil environment is and the more I
read the more I am amazed. Sometimes I think it really would be *much*
easier if I just installed full irrigation and stuck with using
"artificial" fertilisers but I just can't bring myself to do it!

To finish, and complete the circle, back to green manures: if I had more
time I think your idea is better than mine. The problem is that I really
need my garden "water-wise" and planted no later than November this year.
Given even more time I would love to plant lucerne and let it grow for the
full two years before slashing it down - apparently the roots of the
lucerne will go as deep as 3 metres over a two year period - now that's
what I call adding organic matter! Since I plan to have a total of 6 beds
it is not impossible that once the whole garden is properly formed and
layed out I can actually do this by having four beds for vegetables and two
beds for green manuring. *SIGHS* - what a pity nature takes so long when I
have so little time

Thanks again for the reply and great idea

Ivan.