Fact or fiction?

 

I seem to remember that wood as it decomposes uses up the nitrogen in
the soil. Not really good for the garden.  Old wives tale or true?

--
USA
North Carolina Foothills
USDA Zone 7a

 



True, with a caveat or two:  Any material absorbes nitrogen as it
decomposes.  If it doesn't contain much nitrogen of its own, the deficit
comes from its surroundings.  Having said that, if the wood chips or
whatever are on the surface, they won't steal much N from the soil under
them.  And if the "brown" material is partially rotted already, there's
less of an issue.  
So, let it rot and weather as mulch before turning it in, or partially
compost first, and you'll be fine.


Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
Zone 5/6 in upstate New York, 1420' elevation. NY WO G

 



 I think of rotting as burning.  Everything burns up some faster than
others.  Rusting is oxidation  aka a slow burn.  

A book that touches on this as a side issue is "Arctic Dreams " which
notes the slow decay in arctic areas.  Dead animals and foot prints
about for years.  Many stars and due for a reread.

--
   Bill   Garden in shade zone 5 S Jersey USA
 

 

Bill who putters wrote:

A better way of describing it would be being eaten rather than burnt.
Burning doesn't involve nitrogen whereas the microbes that decompose wood do
use up nitrogen as well as oxygen.

Gary had it pretty well right.  Nitrogen is used up to some extent but it
may not be an issue and it gets returned later.  The situation has to be
fairly extreme for nitrogen draw down to severely deplete the soil.  This
can be used to your advantage by using sawdust on paths, little or nothing
will grow in it for a year or two.

David

 



In terms of both its physical and chemical properties, wood is an
exceptionally difficult substrate to degrade. One of the principal
reasons is that wood contains very low levels of nitrogen, which is
needed to produce the enzymes that degrade the main structural polmers
of wood - cellulose (about 40-50% of the dry weight of wood),
hemicelluloses (25-40%) and lignin (20-35%).

The lignin component also presents a barrier to wood decay because
lignin is a complex aromatic polymer that encrusts the cell walls,
preventing access of enzymes to the more easily degradable cellulose and
hemicelluloses. In addition to these points, wood often contains
potentially fungitoxic compounds, which are deposited in the heartwood.
In broad-leaved trees the toxic compounds are usually tannins, well know
for their ability to cross-link proteins, making animal skins resistant
to decay. In contrast, conifers contain a range of phenolic compounds
such as terpenes, stilbenes, flavonoids and tropolones. The most toxic
of the tropolones are the thujaplicins which act as uncouplers of
oxidative phosphorylation; they are particularly abundant in cedarwood,
making this a naturally decay-resistant wood for high-quality garden
furnishings, etc.


http://www.biology.ed.ac.uk/research/groups/jdeacon/FungalBiology/woodrot
s.htm

When the nitrogen is no longer needed for enzymes or fungal growth, it
is released back into the soil environment for use by other microbes,
and plants.
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.

http://www.thirdworldtraveler.com/Zinn/HZinn_page.html