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Lightweight Peat's Mucky Muck soil testing
- Thread starter biggreg
- Start date
biggreg
Member
Effective CEC is the number of exchange sites at any given ph.
The barium cloride compulsion test can be a direct measure of effective CEC at any ph. This test isn't normally done.
Summation of the base cations and estimated acidity from the lime buffer or calculation from a routine soil test Is the estimated CEC @ph 7.0 or TCEC.
CEC is used by some state universities to adjust SLAN Mg K or P fertilizer recommendations.
For the purpose of balancing soils via BCSR ratios, the CEC @ 7.0 is the scale that is used.
The barium cloride compulsion test can be a direct measure of effective CEC at any ph. This test isn't normally done.
Summation of the base cations and estimated acidity from the lime buffer or calculation from a routine soil test Is the estimated CEC @ph 7.0 or TCEC.
CEC is used by some state universities to adjust SLAN Mg K or P fertilizer recommendations.
For the purpose of balancing soils via BCSR ratios, the CEC @ 7.0 is the scale that is used.
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Really interesting stuff. The article on "muck soils" is interesting.
biggreg
Member
My main message to all testing their recycled, peaty, lightweight, mucky muck, non mineral soil, container soils is to:
Make the lab weigh in the sample to get an accurate mg/kg and Meq/100g report
Measure your own bulk density in g/cc
Convert the mg/kg to mg/l and meq/100g to meq/L to give the numbers perspective. That is the key. Unlike with mineral soils which the report is pretty much reads both mg/kg and mg/l with the same number, ppm and CEC need to be looked at volumetrically in soils less dense than 1g/cm3 to have meaning.
From there you can balance cations by weight or adjust to typical levels per volume.
Make the lab weigh in the sample to get an accurate mg/kg and Meq/100g report
Measure your own bulk density in g/cc
Convert the mg/kg to mg/l and meq/100g to meq/L to give the numbers perspective. That is the key. Unlike with mineral soils which the report is pretty much reads both mg/kg and mg/l with the same number, ppm and CEC need to be looked at volumetrically in soils less dense than 1g/cm3 to have meaning.
From there you can balance cations by weight or adjust to typical levels per volume.
biggreg
Member
I'm curious to compare our soils.
What's your CEC meq/100g
What's your bulk density?
Meq/L? (Also can be expressed meq/100cm3, just move the decimal)
Target ph?
Base cation ratio goals?
Suffiency levels goals ( in mg/L)
Micronutrient level goals? (In mg/L)
Teqniques for correlation and calibration of these tests to actual results?
Favorite labs?
Also let's share our at home testing tequniques, ph testers, bulk density, lime requirement tests, EC, other meters, etc.
What's your CEC meq/100g
What's your bulk density?
Meq/L? (Also can be expressed meq/100cm3, just move the decimal)
Target ph?
Base cation ratio goals?
Suffiency levels goals ( in mg/L)
Micronutrient level goals? (In mg/L)
Teqniques for correlation and calibration of these tests to actual results?
Favorite labs?
Also let's share our at home testing tequniques, ph testers, bulk density, lime requirement tests, EC, other meters, etc.
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biggreg
Member
On labs so far I've found that run the Mehlich 3
1. The never scoopers
MB Labs in B.C. Canada
They claim to not even own a standard weighing scoop. You specify which extractant. Their standard is a locally developed Kelowna extraction. They will sub the Mehlich3 upon request.
They run a pretty complete standard package for home gardeners that includes : Nitrogen (N), Phosphorus (P), Potassium (K), Sulfur (S), Sulfate, Organic Matter, Major & Minor Elements–including: B, Ca, Co, Cu, Fe, Mg, Mn, Mo, Si, Na, Zn, pH & Conductivity (Salinity) cost $73.50 CAN ( exchange rate helps)
Exact scientific in WA. They don't own scoops either. Must request Mehlich 3
Soiltest lab in WA. Same as above
I was told by a Midwestern lab that labs in WA do not scoop due to wacky soils.
2. The scooper labs that say they will weigh with a real analytical balance upon request, you should call first. It's not their standard. Make sure to check their assumptions on CEC calculations, mineral soil conventions will throw the test.
Spectrum Analytic ( extra handling charge)
Rock river labs
A&L Great Lakes
Agvise ( must request Mehlich 3)
3. The scoop only labs: the ones who say no
Logan
Midwest
Brookside
Dairy one
AgSource
Ward labs
American Ag lab
I will keep calling around to add to the list.
1. The never scoopers
MB Labs in B.C. Canada
They claim to not even own a standard weighing scoop. You specify which extractant. Their standard is a locally developed Kelowna extraction. They will sub the Mehlich3 upon request.
They run a pretty complete standard package for home gardeners that includes : Nitrogen (N), Phosphorus (P), Potassium (K), Sulfur (S), Sulfate, Organic Matter, Major & Minor Elements–including: B, Ca, Co, Cu, Fe, Mg, Mn, Mo, Si, Na, Zn, pH & Conductivity (Salinity) cost $73.50 CAN ( exchange rate helps)
Exact scientific in WA. They don't own scoops either. Must request Mehlich 3
Soiltest lab in WA. Same as above
I was told by a Midwestern lab that labs in WA do not scoop due to wacky soils.
2. The scooper labs that say they will weigh with a real analytical balance upon request, you should call first. It's not their standard. Make sure to check their assumptions on CEC calculations, mineral soil conventions will throw the test.
Spectrum Analytic ( extra handling charge)
Rock river labs
A&L Great Lakes
Agvise ( must request Mehlich 3)
3. The scoop only labs: the ones who say no
Logan
Midwest
Brookside
Dairy one
AgSource
Ward labs
American Ag lab
I will keep calling around to add to the list.
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biggreg
Member
Hey, just found this info:
4. Labs that don't weigh the sample at all--Volumertic testing.
Looking into all these lab's methods, I decided to look into labs in North Carolina, knowing that state has lots of histosol crop land.
Dr. Mechlich worked for the North Carolina Department of Ag where he developed the Mechlich 3 test with Carolina histosols and mineral soils in mind. His Mehlich lime requirement buffer test was also designed with higher organic matter soils. Maybe the Mehlich is the right test for our soils?
Labs in this state seem to all report volumetrically mg/dm3. They test a volume of soil without weighing. Also they give an calculated bulk density. They measure the mass of the dried sample and apply an equation to arrive at the field moist volume.
http://www.ncagr.gov/agronomi/sthome.htm
If you are a North Carolina resident, the Mehlich test is free if you are willing to wait 8 weeks for results. ( they have waiting times on their site)
A&l eastern is also in that state and tests organic soils in the same way.
https://watersag.com/service/soil-analysis/ Is another one.
With a volumetric test mg/dm3 and a bulk density, we could convert it back into mg/kg if we wanted to look at it in soil mass ppm.
4. Labs that don't weigh the sample at all--Volumertic testing.
Looking into all these lab's methods, I decided to look into labs in North Carolina, knowing that state has lots of histosol crop land.
Dr. Mechlich worked for the North Carolina Department of Ag where he developed the Mechlich 3 test with Carolina histosols and mineral soils in mind. His Mehlich lime requirement buffer test was also designed with higher organic matter soils. Maybe the Mehlich is the right test for our soils?
Labs in this state seem to all report volumetrically mg/dm3. They test a volume of soil without weighing. Also they give an calculated bulk density. They measure the mass of the dried sample and apply an equation to arrive at the field moist volume.
http://www.ncagr.gov/agronomi/sthome.htm
If you are a North Carolina resident, the Mehlich test is free if you are willing to wait 8 weeks for results. ( they have waiting times on their site)
A&l eastern is also in that state and tests organic soils in the same way.
https://watersag.com/service/soil-analysis/ Is another one.
With a volumetric test mg/dm3 and a bulk density, we could convert it back into mg/kg if we wanted to look at it in soil mass ppm.
biggreg
Member
Three ways the Mehlich 3 tests are performed by labs on our organic soils:
1. By mass. Organic Soil is weighed in via analytical balance---legit
2. By mass. Organic Soil is weighed in via mineral soil calibrated scoop----NOT LEGIT!
3. By volume. A 2.5cc volume of organic soil is measured in. ----legit
1. By mass. Organic Soil is weighed in via analytical balance---legit
2. By mass. Organic Soil is weighed in via mineral soil calibrated scoop----NOT LEGIT!
3. By volume. A 2.5cc volume of organic soil is measured in. ----legit
biggreg
Member
The at home lime requirement test:
Peat soils have a widely variable lime requirement to bring the acidity up into plant happy range. 3 to 4 grams per L typical up to 15g per L for the really broken down mucky mucks.
Measure out 3 or more 1 Liter samples of soil and weigh in increasing amounts of lime. I weigh 38% Ca micronized lime into a tared glass of distilled water and add it to the sample. Then rinse out the glass with more water to be sure all the lime goes into the soil.Mix sample well and incubate the sample at garden conditions ( temp and moisture)for a week or so until ph is stable. ) I get a stable reading after 3 or 4 days , stirring soil daily, but wait at least a week or longer to be sure. With those ph readings, we can graph the linear response and get the amount in grams needed to hit a target ph.
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biggreg
Member
Base Cation Saruration Ratios (BCSR) can be manipulated in our mixes working in soil mass ppm or mass volume ppm
Or
If you ain't into BCSR, and rather look at Suffiency Levels of Applied nutrients (SLAN), then mass per volume ppm is what you need
Convert your soil mass ppm test numbers to mass per volume ppm numbers with your a bulk density test. This reframes the soil mass ppm numbers into numbers that match mineral soil data and are compareable to one another.
Or
If you ain't into BCSR, and rather look at Suffiency Levels of Applied nutrients (SLAN), then mass per volume ppm is what you need
Convert your soil mass ppm test numbers to mass per volume ppm numbers with your a bulk density test. This reframes the soil mass ppm numbers into numbers that match mineral soil data and are compareable to one another.
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biggreg
Member
Let's say your lab weighed in your sample and reported in mg/kg or ppm soil mass. Your Ca is 6000ppm. Is that enough or too much?
Your bulk density is .2g/cc
Your ppm - mg/l is 6000x.2= 1200ppm. Right In the suffiency range With equal grams of Ca per container as a mineral soil weighing 1g/cc with a 1200ppm -soil mass.
Plants grow in a volume of soil, not a mass of soil.
Your bulk density is .2g/cc
Your ppm - mg/l is 6000x.2= 1200ppm. Right In the suffiency range With equal grams of Ca per container as a mineral soil weighing 1g/cc with a 1200ppm -soil mass.
Plants grow in a volume of soil, not a mass of soil.
biggreg
Member
If you have a soil test in which the lab "weighed"your organic soil sample with a mineral soil scoop, your report is neither in mg/kg or mg/L. The numbers on that wrongly executed test can only show a general direction of the soil. Those numbers do not reflect the grams of the elements in the mass of the soil nor the grams of the elements in your volume.
biggreg
Member
Labs performing Mehlich 3 extractions differ on calculating the CEC. If you're playing with BCSR ratios, the reccomended method is a total CEC calc including Ca+Mg+K+Na also accounting for other bases and exchangeable acidity. Logan Labs uses this method to give a TEC as they call it. See attached. In their equation, divide the lbs/acre number by 2 to add it up in ppm (soil mass)
Or use this calculator
https://growabundant.com/calculate-tcec/
Or use this calculator
https://growabundant.com/calculate-tcec/
biggreg
Member
Lets look at a side by side of the same soil and the same lab both by mass and volume:
Check out the attachment for the test results in ppm mass per volume of extract solution. This number is equal to the soil mass ppm if 2g of soil is correctly measured in the test. We have no idea what the mineral soil scoop weighed in, we just know it's less.
Here is the soil mass equation,from the SERA lab manual, used to convert units mg per L in the test extract to ppm soil mass, mg/kg on the final report:
Check out the attachment for the test results in ppm mass per volume of extract solution. This number is equal to the soil mass ppm if 2g of soil is correctly measured in the test. We have no idea what the mineral soil scoop weighed in, we just know it's less.
Here is the soil mass equation,from the SERA lab manual, used to convert units mg per L in the test extract to ppm soil mass, mg/kg on the final report:
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biggreg
Member
Let's look at the BCSR ratios calculated in the brookside/Logan labs TCEC method. I didn't test Na by mistake so we will call it zero
2g sample. = TCEC 44.95, 69.3% Ca, 13.6% Mg, 4.69%K
"2g" scoop. = TCEC 32.51, 70.86% Ca, 12.48%Mg 4.25%K,
The ratios are close but the CEC is off on the scoop to weigh sample
2g sample. = TCEC 44.95, 69.3% Ca, 13.6% Mg, 4.69%K
"2g" scoop. = TCEC 32.51, 70.86% Ca, 12.48%Mg 4.25%K,
The ratios are close but the CEC is off on the scoop to weigh sample
biggreg
Member
Now let's convert from soil mass to mass per volume and look.
A cubic centemeter of this soil at field moisture that has been dried weighs .363g.
If Ca is 6230 mg/kg and bulk density is .363g/cm3, then the soil has 2261 mg Ca/L
If Mg is 734 mg/kg, then the soil has 266 mg/L
K is 823 mg/kg then we have 298 mg/L
The TCEC is 16.31 meq/100cm3 this soil has the cation exchange capacity equal to 16.31 meq/100g mineral soil.
A cubic centemeter of this soil at field moisture that has been dried weighs .363g.
If Ca is 6230 mg/kg and bulk density is .363g/cm3, then the soil has 2261 mg Ca/L
If Mg is 734 mg/kg, then the soil has 266 mg/L
K is 823 mg/kg then we have 298 mg/L
The TCEC is 16.31 meq/100cm3 this soil has the cation exchange capacity equal to 16.31 meq/100g mineral soil.
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