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livingontheland - Re: [Livingontheland] Humus: Still a Mystery

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Subject: Healthy soil and sustainable growing

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  • From: "TradingPostPaul" <tradingpost@riseup.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: Re: [Livingontheland] Humus: Still a Mystery
  • Date: Tue, 13 Jun 2006 22:00:09 -0600


The way I read it, cold soil inhibits microbial activity. The reason
tropics have lower humus levels in general is higher temperatures tend to
literally burn - oxidize - humus as it's produced. And in aerated soil,
more of it is exposed to oxygen, hence faster oxidation of the humus.
That's one problem with tillage, as our no-till advocates would point out.

I have no doubt humus levels can be raised above the original levels of
local soil, and I think Albrecht was way out in left field when he (and
Steve Solomon) claimed otherwise. Whether it's practical on a large scale
in a certain soil may be a different matter, but in general, of course you
can. I've read that about 5% humus level is ideal. Prairie grasslands are
noted for root mass and high humus levels.

paul, tradingpost@riseup.net
---------------
The outstanding scientific discovery of the twentieth century is not
television, or radio, but rather the complexity of the land organism. Only
those who know the most about it can appreciate how little we know about
it.
- Aldo Leopold in Round River, 1933
*********** REPLY SEPARATOR ***********

On 6/13/2006 at 2:44 PM blademan25@yahoo.com wrote:

>The following 3 sentences in this article - seems to
>be in conflict with itself - or maybe I am mis-reading
>it???
>
>
>Soil temperature is another important controlling
>factor in the formation of humus. As the temperature
>of a soil increases, there is a corresponding
>increase in microbial activity.
>
>Soils that exist in warmer regions of the earth tend
>to have lower native levels of humus than soils in
>colder areas.
>
>Figure 1 shows that at a temperature of 88 degrees F,
>in well aerated soil, humus can no longer accumulate.
>Is this temps above 88 - or below 88?
>







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