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Thursday, 15 November 2007 |
Lindsay Woodster finds out about a revolutionary method of soil regeneration.
The first national conference took place
in Figeac recently on the astonishing
properties of what is called ramial
chipped wood (RCW). The French equivalent
is BRF (standing for Bois Raméal Fragmenté).
This is the method of chipping branches of
7cm diameter or less, and spreading them
immediately on the soil.
It was discovered in Quebec by the
Forestry Minister who was looking for a use
for logging residues. It has since been
developed further in Canada, as well as in
Africa and is now taking hold in France.
Wood of this size is high in soluble lignin,
and contains all the nutrients necessary for
soil generation. Its promoters have found that
soil productivity is massively increased within
at least a year, and in hot climates can give
amazing results within months. Improvement
to the soil structure and nutrient levels is
found to last for up to a decade.
I had always thought that new vegetation
added to soil inevitably used up the nitrogen
content to degrade and so I’ve always
composted any woody clippings from the
garden. Big mistake. RCW has a short-term
impact on nitrogen levels, but these rise again
rapidly to finish much higher than before. The
qualities of the forest floor are all to be found
in the developing new tilth, with improved soil
structure, rapid development of mycorrhiza
and, in particular, high humidity retention so
less need to water young plants.
Yield increases have been reported from
all areas using this system: up to 1,000% for
aubergines in horticultural cultivation in
Senegal; 290% for strawberries in Canada;
and elsewhere massively improved yields of
cereals and potatoes.
How to use RCW
First get a chipping machine to share with
friends, and do as much chipping as possible
all at once. Use only small branches and
twigs, mostly of mixed deciduous hardwoods,
with a maximum of 20% conifer. Ask the local
commune for all their prunings from those
planes and other shade trees that spend the
winter with knobbly limbs exposed.
Make chippings no larger than 3cm in
diameter, and use them within 24 hours.
Spread a 3cm layer on the soil surface, this
being 30m3 per 1,000m2.
Wait three to four months and observe the
rapid development of white fungal threads in
the layer. Mix the whole lot into the top 5cm
of soil. Sow or transplant into the tilth and do
not disturb it further.
Repeat the process four or five years later.
http://users.skynet.be/BRFinfo/tronc/Frame.htm
http://forestgeomat.for.ulaval.ca/brf
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