Lightweight Peat's Mucky Muck soil testing

[acespicoli]

I know its a factor of 10 multiply 1000*1000 1 million?

 

[acespicoli]

calcium / 1,000,000 units of soil = ppm

 

[acespicoli]

5000mg/1,000,000=? 5000ppm just seemed high

 

[biggreg]

Find this one ace and you'll never forget it. Learn by doing is the only way with this stuff. Just reading it, it all turns to gobbledygook Chinese arithmetic, clear as mud, Charlie Brown's teacher wa wa.

Write 3 soil scripts and it's in the vault. Easy stuff for real.

 

[biggreg]

You confident in your 5000ppm answer?

 

[biggreg]

At 5000mg/kg , Ca is 100% saturated into the exchange sites of a 25 meq/100g soil.

Ca = 20mg per 1 meq/100g

So 20mg/meq/100g x 25 meq/100g = 500mg/100g

So 500mg/100g x 10 = 5000mg/kg or 5000 ppm soil mass

Why is that useful to know if you wanted to balance some 25meq/100g soil?

 

[biggreg]

What should the ph be at 100% saturation with Ca and zero free carbonates?

 

[biggreg]

To find 100% saturation in mg,
just remember multiply CEC by:

200mg for Ca
120mg for Mg
390mg for K
230mg for Na
10mg for H


Once you have a mg ppm for 100%, multiply by your target %:

For this imaginary 25 meq/100g soil,
68% Ca = 3400ppm
82% Ca = 4100ppm

12% mg = 360ppm

5% K = 478.5ppm

1% Na = 57.5ppm

Those could be your targets, or use other targets if you wish.

 

[biggreg]

Would the ppm be the same if the CEC was 25meq/100cm3? ( per volume)

A: only if the bulk density is 1

 

[jidoka]

What should the ph be at 100% saturation with Ca and zero free carbonates?

7

 

[biggreg]

7

Sweet

The Logan/ brookside TCEC calculation attempts to find the CEC at ph7.0 to base the Albrecht ratios on.

There is a AA7.0 CEC test in the lab manuals that directly measures CEC at 7.0ph. It's NOT the AA7.0 cation extraction test with a summation of CEC.

Since it doesn't count Calcium, mg, K or Na, ( it washes them all out with NH4 and counts that, it seems like a solid measure of CEC at 7.0ph or TCEC.

A Mehlich 3 with a calculated TCEC over the directly measured CEC -7.0 has some free carbonates that should be considered.

I'm thinking that test could be a good tool for Albrecht ratio fans.

 

[biggreg]

And please anyone who knows better call out any mistakes I may be making as I type all this shit with my phone. I'm prone to make errors.

Don't believe anything I'm saying, I'm not any kind of authority . Just look to the info and concepts I'm pointing to and see it for yourself.

Also,

If I'm seeing it wrong, please show me the light. That's why I started posting in this thread.

Thanks.

 

[biggreg]

One truth I can preach to you lightweight soil lovers is this verifiable horrific mis-reporting reality:

 

[acespicoli]

biggreg I really appreciate our soil testing discussions it gets my mind moving
Your patience with me admirable thanx

 

[biggreg]

Q: I've been using scooped tests and amending as if that test was reported on a volume basis and I'm able to balance the cation ratios pretty well. How does that work?

A: Most of the scooped tests I've seen posted up have CECs in typical mineral soil ranges of 12-25 or so. These scooped values are skewed low. The actual CECs per mass (meq/100g)are double or triple or more dependent on the density but the CEC per volume (meq/100cm3) will typically fall in that same range. So by amending your required grams based on target soil mass ppm assuming a BD of 1, you are amending as if the CEC per volume ( meq/100cm3) was your scooped estimate of meq per mass (meq/100g). It's fuct-up but it works mostly and is a source of confusion

Said another way, your scooped meq/100g is way low but if use that value as your meq/100cm3, you are probably close to your actual CEC per volume (meq/100cm3)

Clear as mud yet?

 

[biggreg]

biggreg I really appreciate our soil testing discussions it gets my mind moving
Your patience with me admirable thanx

I appreciate you were the first to offer friendship.
I appreciate your eager energy.
Thanks for the paper on Si and Ca content of cannabis resin glands. I've so been missing the boat on Si and will start testing for it.

 

[biggreg]

From North Carolina Departmenr of Ag (NCDA) on understanding their style ( volumetric) reporting:

"The CEC of North Carolina soils ranges from low (less than 2.0 meq/100 cm3) for sandy soils to as high as 25 meq/100 cm3 for clay and organic soils."

That's meq/100cm3. Not meq/100g. Per volume CEC of organic soils ( fibric peat in that state) and per volume of clay soils.

This soil I've been tinkering with was directly measured with a CEC-7.0 test that was confirmed with a weighed in, non scooped measured, Mehlich 3 CEC summation has a CEC per mass of 40 meq/100g and the home measured bulk density is .363g/cm3. That means my CEC per volume is 14.5 meq/100cm3.

If i wanted to beef up the CEC to match that 25 meq/100cm3 figure the NCDA says is top of the range there for organic or clay soils, what would my CEC per mass (meq/100g) have to be?

 

[biggreg]

meq/100g x bulk density = meq/100cm3

So,

(X)meq/100g x .363g/cm3 = 25meq/100cm3

25meq/100cm3 / .363g/cm3 = 68.9 meq/100g

 

[biggreg]

I'd really like to see some true "water only" soils tested for CEC and bulk density for a per volume CEC with data on the container size.

Try to find the real "water only" CEC tipping point for various sized containers.

I realize other variables would come into play like soil life and strain. But maybe we could get a decent idea?

I'm interested in water only soils for the purpose of making it easy for medical growers in need. I'd love to give someone who would benefit an autoflower start in a suitable size container, tell them to put it in their greenhouse and water. ( backyard greenhouses are very common here in Alaska and so is 20 hours a day of light!)

Medical needs cannabis consumers may not be able to afford paying crazy street/retail prices. They should grow their own if possible.

 

[biggreg]

Let's assume a stable, not recently amended, Calcium dominate soil and cation ratios calculated using the CEC @ 7.0ph ( TCEC)

So if 100% of the soil's exchange sites are saturated with mostly Ca,some Mg, a little K, tiny Na and micro amounts of other bases, we have ph 7.0.

A Calcium dominate ratio at that ph 7.0 could be 82%Ca-12%Mg-5%K-1%Na and other micro bases.


What could a Calcium dominant cation ratio be at ph 6.5 ( the most common target ph Ive seen reccomended for high demand vegetables based on standard SLAN field trials)