[permaculture] [Fwd] Soil Fertility

Lawrence F. London, Jr. lfl at intrex.net
Sun Jun 24 04:15:34 EDT 2007

-------- Original Message --------
Subject: Re: [SANET-MG] nutrition in a bottle or a bag?
Date: Sat, 23 Jun 2007 22:39:30 -0700
From: Tanya Kucak <yarrow at SFO.COM>

At 12:12 PM -0700 6/19/07, Edna Weigel wrote:
 >....While I'm not prepared to argue against small,
>supplemental additions of depleted nutrients where needed, I'm a great
>believer of adding organic matter (which often includes many needed
>nutrients--this can include growing whatever cover crops will grow in the
>depleted soil) and adjusting pH where it is acidic (which, I've read many
>times, is exacerbated by chemical fertilizers) then allowing microbial life
>to "unlock" the nutrients that are already there.

The most interesting work on soil fertility I've seen is a few short
papers by Roland Bunch based on the work of Ana Primavesi. Basically,
she describes the traditional approach to fertilization as the
Nutrient Quantity Concept -- the notion that specific nutrients need
to be supplied to plants in periodic large doses -- and proposes that
in the tropics, the Nutrient Access Concept is more important. This
is the notion that plants need constant access to tiny quantities of
nutrients, best supplied by nurturing the soil biology and using
sufficient compost and mulch.

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