[Pil-pc-oceania] Soil Fertility:-William Albrecht

[David Arnold]

There are minerals contained in the organic matter, which of course varies
depending on the quality and quantity of the organic material.  Vegetable
gardeners can supply all or almost all of their soil mineral needs with good
quality compost.

In broader acre situations the big contribution of organic matter to mineral
availability is in feeding soil microbes which in turn make the existing
mineral content of the soil more available to plants.  Enhanced soil biology
buffers mineral imbalances and can create a good growing environment, as
long as the mineral content of the soil holds out.

On some farms the enhanced soil biology [eg using Bd methods or other
strategies, incl. soil aeration] can turn the farm around for 10 years or
so, but if the farm continues to export produce some minerals can become
critically depleted and soil remineralisation is necessary.

dave




On 17/04/2008, Laurence Gaffney <l.gaffney at bigpond.com> wrote:
>
>  Thankyou James for your summary of Albrecht. It was helpful.
> There appears to be a connection between loss of soil organic matter and
> imbalanced minerals particularly Calcium.
> What specific affect would increasing soil organic matter have on these
> numbers?  This is Inghams area I think, but am still searching for
> good information.
>
> Laurence Gaffney
>
> Date: Mon, 7 Apr 2008 10:47:52 +1000
> From: "James Sprunt" <james.sprunt at gmail.com>
> Subject: Re: [Pil-pc-oceania] Soil Fertility:- Albrecht and Ingham
> To: "'permacultue discussion list'"
> <pil-pc-oceania at lists.permacultureinternational.org>
> Message-ID: <47f96f3f.09038e0a.1246.5625 at mx.google.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Dr William Albrecht - a Professor of Soils at Uni Of Missouri.
>
> He did thousands and thousands of soil tests and found that a key to plant
> nutrition was to have balanced minerals in the soil. He suggests that it is
> very important to have balanced cations in a soil whereby cations Ca 2+, Mg
> 2+, K+, H+ (pH), Na+, and to a lesser extent NH4+ and Al3+ attach to
> negatively charged colloids (tiny particles of clay and humus) in the
> approximate ratio (in a loam soil), 68%, 12%, 5-8%, 12%, <5%, <1%.  If the
> soil minerals are imbalanced, plants are unable to access certain
> nutrients.
>
> This infers just how little information pH by itself gives in that all of
> these cations affect pH e.g if had low Ca, H could be very high (pH low,
> very acid), or Mg might be very high and H good (pH slightly acid).
>
> So for example, if H+ =12% (pH approx 6.2) one may not think to do
> anything. However, Mg 2+ may be around 25% which  give a very tight, sticky
> when wet, cracks when dry soil. So one could still add lime (Calcium) which
> would
> displace Mg from the colloid but based on pH alone one might not do
> anything. My family's farm in northern Victoria which had quite fertile
> sandy clay loams, were quite acidic pH 5.5 with high levels of Mg. Without
> the cation information one might apply Dolomite lime which would add
> Magnesium further distorting the balance. Agricultural lime was applied to
> improve the balance (kick some of the Mg off the cation) and improve pH by
> displacing some H+  off the cation.
>
> Most soil tests supply cation results although not all of them give a
> figure for H, except as a pH. APAL in SA use the Albrecht system.
>
> Elaine Ingham also talks about getting the mineral balance right. Her
> primary avenue though is through the biology of the soil, the Soil food web,
> which can also affect the pH, cation exchange and the available nutrients.
> Feeding the soil food web through well made compost and aerated compost teas
> she can affect the composition of the soil biology by the ingredients in the
> compost. For example, for tree crops, the soil requires a higher ratio of
> fungi to bacteria so the compost comprises of more woody material.
>
> Hope this helps,
>
> James
>
>
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-- 
David Arnold
Permaculture Designer
4446 Murchison Rd
Violet Town VIC AUS 3669
03 5798 1679
arnold.vt at gmail.com

www.youtube.com/murrnong
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