[Terrapreta] CORRECTION re: Terra preta 101

[Frank Teuton]

Allan,

Alkalinity is high pH, ie, pH over 7.0.....acidity is low pH, ie, pH under 
7.0.....for agricultural purposes acid soils are less than 6.0 pH, alkaline 
greater than 7.0, and neutral soils are in the 6.0-7.0 area.

Conventionally, limestones are added to raise the pH....sulfur to lower 
pH....the additions of organic matter in its myriad forms tends to mildly 
lower pH and to strongly buffer the soil (making pH changes more difficult 
to achieve).

Washed charcoal ought not to change the pH at all, but the unwashed will 
tend to be alkaline due to ash content. This in turn will tend to be a 
temporary alkalinity due to the highly soluble nature of ash ingredients. 
Increased alkalinity means the pH is raised, not lowered.

HTH,

Frank Teuton
----- Original Message ----- 
From: "Allan Balliett" <aballiett at frontiernet.net>
To: "Michael Bailes" <michaelangelica at gmail.com>; 
<terrapreta at bioenergylists.org>
Sent: Thursday, September 20, 2007 5:54 AM
Subject: [Terrapreta] CORRECTION re: Terra preta 101


> Mihael Bailes said:
>
>>Charcoal will lower pH. Ash will lower it drastically
>
>
> Like I often do, I think you flipped a bit on what moves soil sweet
> and what moves it sour.
>
> Here's a comment from the U of Conn on the affects of wood ash on garden 
> soils:
>
>>Wood ash acts on the soil much like limestone in that it raises the
>>pH or alkalinity of the soil. Consequently, many wood stove burners
>>dump the ashes on their garden site with the thought that they are
>>improving the soil condition of their garden. Yet unlike limestone,
>>which can take six months sunfloweror more to take effect, wood ash
>>has high water solubility and quickly changes the soil pH. This can
>>cause a problem with raising the soil pH over the optimum level of
>>6.5 to 7.0 if we spread too many ashes in the same area. A soil pH
>>over the optimum level can affect plants as adversely as a pH that
>>is too low. High pH will limit the uptake of important soil
>>nutrients needed by the plant such as phosphorous, iron, and
>>magnesium.
>
> I'm here to tell you: you don't want to get your soil pH higher than
> 7.5 if you want your gardening efforts to be productive.
>
> Here's a perhaps off-topic question for you soil scientists: what is
> the relationship between "alkalinity" and 'pH'? I've been lowering
> the pH of my well water (8.2) with the addition of vinegar for foliar
> spraying and find that test strips may show a pH of 6.0 but we are
> still over the top on alkalinity, even if I add an agricultural soil
> softener and bring us into the test strip 'soft' range.
>
> -Allan Balliett
> Fresh and Local CSA
> Shepherdstown, WV
>