[Terrapreta] making a new top soil

[Robert Klein]

A really interesting experiment would be to plant
alfalfa in a very thin top dressing that included fifteen percent biochar on a
subsoil base.  It is the nature of
alfalfa to run a root system both deep and broad while also fixing
nitrogen.  This penetrates the sub soil
with organic material on an ongoing basis.  The top dressing holds the soluble nutrients also needed.  The question that we are really asking here
is whether this protocol is able to produce a viable top soil quickly.  While this is going on, it may be possible to
harvest some of the alfalfa and perhaps aerate the top three inches.  Obviously any now barren non productive field
could be used for this experiment and I expect the carbon to counter even
salinity by sequestering the salts into the carbon.
The important point is that the initial top dressing
does not need to be very thick, although more will be clearly better.  But if you have an impossible soil, getting anything
to set up and establish itself is a blessing.  The established root material will then start the process of
rehabilitating the soil.  After that it
is a matter of how much of a hurry you are in.  An established alfalfa field providing a steady and improving supply of
fodder is at least nicely carrying itself.I wrote this for my blog today and i think it is worth sharing.

arclein at 

http://globalwarming-arclein.blogspot.com