[Terrapreta] interesting situation

[MFH]

Jim,

My recent soil tests give data like:

Calcium (Mehlich III)		389ppm (ideal = 1347)
Magnesium (Mehlich III)		384ppm (ideal = 157)
Ca/Mg ratio				0.61:1 (ideal = 5.15:1)

The explanatory notes include:

CA/MG Ratio:  This is the single most important fertility ratio and should
be around 5:1 for light soils and 7:1 in heavier soils. Low Ca/Mg ratios are
usually indicators of serious problems. These include compacted soils,
bacteria that can't proliferate, and weed take over. An appropriate Ca/Mg
ratio will be an obvious consequence of the successful achievement of cation
balance.

>From other sources, if the CA/MG ratio is below 2, it is difficult for the
plant to take up potassium.

There's lots of web info available, e.g:
www.spectrumanalytic.com/support/library/ff/Ca_Mg_ratio.htm

Cheers, Max H



-----Original Message-----
From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Jim Joyner
Sent: Friday, 9 May 2008 10:05 AM
Cc: Terrapreta at bioenergylists.org
Subject: Re: [Terrapreta] interesting situation

MFH wrote:
> Calcium/Magnesium ratio is critical. Should be 5:1 for light soils and 7:1
> in heavier soils.
>
> Max H
Max,

I think calcium and magnesium are critical in the soil but I have never 
seen soil tests express it that way. I thought the ideal 
calcium/magnesium would be a a percentage of base saturation (70%/12%). 
Having said that, however, when Richard got his numbers, I believe the 
results showed less calcium as a % than that, but "high". Is there 
something you know that I don't?

Thanks,

Jim

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