-style


>The land would revert back to it's rich state if left
>alone, because that is what it did after the last
>ice age.  That only happens if the loop is closed.
> If you are
>harvesting from a set plot of land, wether it
>is a crop or cattle, you are removing atoms from the
>land and depleting the chemistry.  The key element
>is usualy phosphorus.  When left alone minirals
>(atoms) are chelated from the native bedrock at
>a slow rate, and fertility imporves unless
>erosion is removing the material.  Thus the
>Great Plains had accumulated in some places
>tens of feet of rich topsoil since the ice age.
>
>With a little intelligent management the land can
>be quickly returned to a very fertile state.
>One key to sustainable agriculture is to recycle
>the human waste back to the land so the loop
>is closed and then fertility improves.
>
>Whether this will happen on a large scale in our
>lifetimes remaines to be seen.  The only way this
>could happen is if oil becomes more scarce and
>agriculture is forced back to organics.  This is
>just beginning to happen, but may be too little
>too late.
>
REcycling humans wastes back to the land will at the most maintain the
initial fertility but in any way will augment it . Only a land supporting a
rich varied ecosystem  in an untilled soil have the capacity to have his top
soil grow,  because of the maximum used of the sun light  and the diverse
minerals by the differents plants species  ( monocroping or even association
of 2 or 3 plants have little chance to keep the naturel fertilisation going
, and create the necessity of importing nutrients from somewhere else .
Read my previous post same thread on masanobu fukuoka
Jean-claude