permaculture

[Paul Cereghino <paul.cereghino@comcast.net>]

> Is it not the case that roughly 25 parts of carbon need 1 part of nitrogen
>  for composting to occur
I have seen this 25:1 ratio as a recommendation for optimizing the rate 
of bacterial decomposition (hot aerobic pile) without loss of surplus N 
as ammonia gas (old urine smell).  Compost will occur under a range of 
conditions just smelly or slowly.

> I thought I had 
>  observed that a thick layer of very fine carbon rich material like saw dust 
>  does inhibit plant growth.
I don't think I am contradicting Robyn... that the right mulch on the 
right soil could soak up available nitrogen from surface soils.  I have 
also seen thick wet sawdust make soil underneath anaerobic, and ethylene 
gas produced from anaerobic decomposition can directly hurt plant 
roots.  I think we are back in one of those 'it depends' situations.

Paul Cereghino
Olympia, WA