Billy wrote:
songbird wrote:
Billy wrote:
...
Feel free to offer some citations for your responses, otherwise it is
just opinion, and you know what they say about opinions.


from _Permaculture_, Bill Mollison, 1990 p. 377

And this would be "Permaculture : a designer's manual / by Bill Mollison
; illustrated by Andrew Jeeves", 576 pages, Tagari Publications
(December 1988)

Good thing his books are available at the library. They are very pricy.

been a very interesting read. i think the
general information in it is worth contemplation.
i'm not sure some of his political or other views
are really needed, but how could anyone write
such a large topical book like this and not
wander off on a few rants here or there?

sadly, it really needed a good editor and more
proof readers to catch the many textual layout
mistakes, miswords, and outright factual errors.

[moles don't eat/store bulbs, but they may shift
them a little bit in their diggings -- other
creatures that use their tunnels may eat and store
bulbs, but that is a whole different thing...]


"SOILS

In drylands, any soil humus can rapidly decompose (in
dry-cracked soils) to nitrates with heat and water,
giving a sometimes lethal flush of nitrate to new
seedlings. Dry cultivated soils exacerbates this effect.
Mulches or litter on top of the soils prevents both soil
cracking and the lethal effect of rapid temperature gains
that cook feeder roots at the surface, so that in
subsequent rains there is less roots to absorb water.

Warm, wet environments also lead to rapid breakdown of organic material
(OM). This is also the reason that healthy soil should only be 5% by
weight, 10% by volume "OM". Otherwise, you'll pollute just like chemical
fertilizers.

i think this can vary, if you have an actively
growing crop with heavy roots already established
then it should be able to soak up extra nutrients
quickly.


Fire is destructive of this protective litter. After fire
and cultivation, most of the soil nitrogen, sulphur, and
phosphorous is lost, and even a cool fire loses plant
nutrients to soil water and leaching. When we know
more of the effects of fire in drylands, it is my opinion
that we will use any other method (slashing, rolling,
even light grazing) to reduce fire litter to soil mulch.
It now seems probable that Aboriginal burning has not
only gravely depleted soil nutrients, but caused a
breakdown in soil structure, and perhaps been in
great part responsible for the saltpans that preceded
agriculture. However, agriculture itself is a mon-
strously effective way to speed up this process and
intensify it."

In the book by Charles Mann, "1492", it was noted that the Amazonians
used "slashed and burn" agriculture, which was detrimental to the land.
Exhausting the laterite soil, they had to move every couple of years
IIRC. Subsequent archeology revealed that the Amazonians had a much more
complex society that wasn't reflected in their "slash, and burm"
agriculture. Prior to the arrival of diseased Europeans, many Amazonians
lead an urban life based on great orchards. However, to protect
themselves against European diseases, Amazonians left their cities to
live in small groups, which survived by subsistent farming.

i suspect it was the fact that the whole area
basically collapsed and the entire social setup
was likely destroyed too. what remained were some
fairly isolated groups and those groups not being
a part of the central peoples may have had taboos
about copying their ways of terra preta or tree
farming. "Look what happened to them! We better
do something different."


an opinion from someone who wrote a primary text on
permaculture. it would be interesting to know what
observations he used to form that opinion. i've
yet to see anyone else make the obvious connection
between grassland burnings and soil depletion for
drylands. to me the thought upon seeing fires almost
anyplace is of all those nutrients going up in smoke.

The soil needs to have organic material in order to hold moisture, and
to feed the micro-organisms that compose the soil ecology, which
ultimately feed the plants. Whether the "OM" is lost by the rapid
oxidation of cellulose in a fire, or the stimulation of micro-organism
in the soil from aeration caused by a plow doesn't make any difference.
Any consistent loss of "OM" from the soil will reduce it's fertility.

yes, but the added harm in fire is that some
nutrients are lost to the air and dispersed.
even those that can float for a long time would
end up 70-80% in the oceans. at least with
localized decays you have a better chance of
keeping trace nutrients in the area.


the book has been interesting overall. i like many
of his perspectives and how to treat an area based upon
the limit of the water supply and that you cannot have
more people than the worst case scenario will support.
also he recognizes overgrazing as the most damaging
problem for many areas that are currently having
trouble feeding people. and like me he laments the
loss of the forests.

The forests, of course, are the source of freshwater.

a big part of it.


songbird