[Terrapreta] interesting situation

[Richard Haard]

Thanks

Actually  I did not post the actual numbers in this transect. Beyond  
these numbers  it seems this gradient in OM percent is an opportunity  
to evaluate charcoal under low OM conditions.

Done at University of Mass. Soil and Plant Tissue testing lab

sample 1 undisturbed soil (0 to 200 feet)
K 130 (high)
Ca 883 (medium)
Mg 105 (medium)
CEC 9.2 MEQ/100 g
%Base Saturation K 2.8 Mg 7.1 Ca 36.5, OM = 3.4%

Sample 2  Scalped by bulldozer to level field (200 to 350 feet)
K 74 (low)
Ca 1058 (high)
Mg 132 (high)
CEC 7.4
%Base Saturation K 2.0 Mg 11.4 Ca 55.4, OM =2.0 %

sample 3 Mixed - soil moved from 2 by bulldozer and mixed with  
undisturbed (350 to 500 feet)

K 119 (medium)
Ca 887 (medium)
Mg 100  (medium)
CEC 8.4
%Base saturation K 2.8 Mg 7.5 Ca 40.8, OM = 3%

Interesting that the subsoil ( sample 2) shows the source of nutrients  
to our soil. And sample 1 and 3 reflect higher potassium from many  
years of application of commercial fertilizer and dairy waste.

It is the gradient in organic matter that defines a interesting  
situation for me. I appreciate your input on Ca/Mg ratios.

Organic Matter is interesting because these low levels may be a place  
where charcoal amendment is beneficial. Our other fields have higher  
levels of organic matter. It will be interesting to treat a strip  
across this field with charcoal and to monitor soil conditions.

Next week I will be taking soil samples for analysis from my 28  
treatment sets. This will be the third in a series for us. I have also  
become interested in sequential soil analysis to monitor our  
management and fertilization practices at our farm.

Rich H

On May 8, 2008, at 5:34 PM, MFH wrote:

> 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

Max from your reference :

However, this does not mean that the specific Ca/Mg ratio is required,  
best, or even related to yield. Research results show that this ratio  
can be as narrow as 2/1 or as wide as 11/1 without negative effects,  
assuming that there is an adequate amount of each nutrient in the soil.

The obvious conclusion is that crop yields are not significantly  
affected by the soil Ca/Mg ratio as long as both nutrients are present  
in adequate amounts.

Interesting stuff this soil test interpretation. As our crops are  
native plants and the subsoil indicated natural background conditions  
I am assuming we are in good condition.

>
>
> 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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