[Terrapreta] nitrogen fertility & terra preta

[Harmon Seaver]

Sean K. Barry wrote:
> Hi 'terrapreta' list,
>  
> It is our hope that Terra Preta formation proves to make soil "hold" 
> nutrients better than it would without the charcoal.  Urea in urine 
> can be a significant source of nitrogen.  Currently, what is the 
> requirement for nitrogen addtions to soil which is cropped?  Doesn't 
> this depend on the crop?  How much anhydrous ammonia is applied per 
> hectare or acre on average to agricultural land?  At what cost? How 
> much of this nitrogen fertilization can be retained in the soil by 
> adding charcoal?  It is presumed that the mechanism for this is that 
> charcoal enhances the growth of soil microorganisms and these are what 
> "hold" the nitrogen in the soil.  Does the kind of soil microorganisms 
> that will do this matter?  Do they need to be "nitrogen-fixing" 
> (Actinobacteria) and etc?
>  
       If it the sold microorganisms that hold the nitrogen in the soil, 
then using charcoal with chemical fertilizer would seem to be a waste of 
time, since those same chemicals destroy natural soil fertility by 
killing the native microorganisms.