permaculture

["Lawrence F. London, Jr." <lflj@intrex.net>]

Toby Hemenway wrote:

> I'm having a hard time figuring out a mechanism for nitrogen to be drawn 
> up more than a couple of millimeters, then across an interface, and into 
> a fresh mulch layer. Rain and gravity will carry N downward. 
> Volatilization might cause nitrogenous gases to rise, but mulch won't 
> have any effect on that. If anything, a mulch layer would slow that down 
> by keeping the soil cool. Movement of N upward seems to require an 
> organism that gets its N in the soil, takes it upward into the mulch, 
> and then eats the mulch carbon to balance the nitrogen, or vice versa. 
> What would move more than a couple of mm? Bacteria won't move that far. 
> Fungal hyphae can transport nutrients, but it would be unusual to have a 
> fungus with intact mycelial strands that cross the interface, from 
> nicely decomposed earth into rough woody mulch. Insects or worms? Maybe, 
> but it seems weird. If someone knows of a mechanism, I stand eager to be 
> enlightened.

I think the usual scenario is when someone tries to rototill significant 
qualtities of fewsh sawdust
or wood chips directly into the top layer os garden soil. Then plants will have a hard time getting established in this 
soil mix. If you add manure or some other source of nitrogen then the problem will be lessened but that is not the way 
to enrich soil; better to mix the sawdust or hay with manure and add rock dusts then put this as mulch on garden surface 
and pland within or better yet prepare the planting zone by planting a cover crop in this mix, clover or vetch.

--
Lawrence F. London, Jr.
lflj@intrex.net
Venaura Farm http://venaurafarm.blogspot.com
Agriculture, Market Farming & Permaculture
http://www.ibiblio.org/ecolandtech