permaculture

[Jay Woods <woodsjay@cox.net>]

The N-starvation effect does exist but only within the layer that is short on 
nitrogen and any source of nitrogen that comes from above. 

If the top layer is wood chips or other high carbon - low nitrogen material, 
anything planted in it will be starved for nitrogen. 

If such a mulch is dug in, it will short the plants for nitrogen. Until the 
mulch composts itself down until the carbon/nitrogen level is balanced the 
effect will show up.

If nitrogen is topdressed, such as from lightning induced nitrogen fixation 
in 
rain water, it will be trapped in the mulch layer until the carbon/nitrogen 
level is balanced. 

The moral is: don't dig in nitrogen short materials, use it as a top dressing 
for weed and water control. It will compost itself into good soil over 
several years.