Glad I could help. I appreciate the appreciation!
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Slownickel lounge, pull up a chair. CEC interpretation
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Glad I could help. I appreciate the appreciation!
I just inquired about that to Payaso. Let's see what the powers that be say.
Part of the reason everyone that uses Spectrum needs Ca can be found in BigRegs thread, post 101 and 102. he is talking about spectrum here
That lab also don't give a *uck about the 2g standard of the M3.
From the chair of the NAPT oversight committee on their practice of only using 1 gram:
"I see a number of labs using 1 gram. In the near future there will be a publication in Comm. Soil and Plant Analyses: Factors Affecting Mehlich III Soil Test Methodology for Extractable P
When it comes out, you will see that higher masses (both weighed and scooped) will result in lower experimental error.
I would question how a lab recovered enough solution from a 1 gram organic sample to run the Mehlich 3, either via ICP or AA-ICP and colorimetric."
The NAPT is bringing this issue along with scooping organic soils up at their meetings this month.
They also have a policy to not count any more than 15 meq Ca towards the CEC calc. That is flat stupid for high CEC organic soils. How many organic soil growers BCSR ratios has that "rule" skewed? Hope people check the CEC summation addition!
I ain't saying Logan does not also have problems, just saying this rabbit hole is deep
That lab also don't give a *uck about the 2g standard of the M3.
From the chair of the NAPT oversight committee on their practice of only using 1 gram:
"I see a number of labs using 1 gram. In the near future there will be a publication in Comm. Soil and Plant Analyses: Factors Affecting Mehlich III Soil Test Methodology for Extractable P
When it comes out, you will see that higher masses (both weighed and scooped) will result in lower experimental error.
I would question how a lab recovered enough solution from a 1 gram organic sample to run the Mehlich 3, either via ICP or AA-ICP and colorimetric."
The NAPT is bringing this issue along with scooping organic soils up at their meetings this month.
They also have a policy to not count any more than 15 meq Ca towards the CEC calc. That is flat stupid for high CEC organic soils. How many organic soil growers BCSR ratios has that "rule" skewed? Hope people check the CEC summation addition!
I ain't saying Logan does not also have problems, just saying this rabbit hole is deep
Yeah, I was in the middle of all that crap.
The lab ran 2 gr, 1 gr, and 2 gr volume scoop and 1 gr volume scoop.
Guess what?
The base distribution didn't change AT ALL.
Yes, there are issues, however, it still gives us the direction. The quantification may not be correct so the numbers are not exact.
The problem with running the 1 gr or 2 gr weight is that these are medias and as you well know the density is a huge issue, not as much as you all would like to make it, but it is an issue.
The correct way to do this is a weighed sample for 1 or 2 grams and then weighing the 1 or 2 gram scoop so that we can discount the weighed sampled and get back to the volume.
I will take Spectrums errors any day over a screwy boron number....
biggreg
Member
I want to thank Slow and this thread for bringing free carbonates to my attention. I have never grown in calcerous soils or in high ph soils. I just assumed that once i allowed my Ca, Mg, and K amendments to cook in my acidic mix and once my ph became stable, I wouldn't have free carbonates.
I will add the 8.2 in the future just to see and will re-evauluate my mixing and incubating techniques to minimize the chances of free carbonates skewing my future tests. The more I learn, the less I know about this stuff. It's great!
On rabbit holes, here is a list of labs and their M3 scoop size and solution ratios done up by the U of Maryland. Spectrum is the only one on the list rocking the 1g /10ml package.
I will add the 8.2 in the future just to see and will re-evauluate my mixing and incubating techniques to minimize the chances of free carbonates skewing my future tests. The more I learn, the less I know about this stuff. It's great!
On rabbit holes, here is a list of labs and their M3 scoop size and solution ratios done up by the U of Maryland. Spectrum is the only one on the list rocking the 1g /10ml package.
R
Robrites
This would be cool. Thread Starters could moderate their own threads.
Oh, please Santa, give me that power!
brown_thumb
Active member
Thread moderation by the OP is possible with most forum software. It's a matter of the moderators agreeing to allow it. From what I understand, it's quite an easy thing to do. I don't think that power should be allowed in all threads but selectively granted to particularly lengthy useful ones, like this, and to those members who have proven their reliability. That stated, there are instances in which excessively heavy-handed moderation results from those allowed it. It's a double-edged sword.
If the moderators here are leery about granting that power then perhaps they could use this thread as an experiment.
If the moderators here are leery about granting that power then perhaps they could use this thread as an experiment.
_tessarecting
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Some point soon I will take samples, mix and divide evenly, and send to logan and spectrum just to see what the differences are
R
Robrites
Oh Great,
Some dude trying to get this thread back on track.
I've already done it months ago. Logan consistently showed lower calcium by at least 5%, lower Mg, and significantly lower B. I've been using Logan for almost three years now and have had success adjusting according to their numbers up until I majorly fucked up with a bag of unlabeled solubor. Long story short I thought it was ZnSO4, plants showed B toxicity but Logan results were only around 3ppm. Spectrum results came back around 11ppm.
Comparing tests within each lab shows consistency (I've sent replicants to both labs multiple times). The differences between each lab are also consistent. There were also differences between the 5 min and 30 min shakes at spectrum but I wouldn't say with certainty that they are significant. Spectrum will also be more expensive than Logan with all the micros included but at this point I don't trust Logan due to the false boron numbers I've seen. It is a major inconvenience to start over with a new lab but that's the direction I'm headed now.
biggreg
Member
In the interest of our collective goal of correct understanding, I would challenge your description of the "correct way" for a lab to perform a Mehlich 3.
Maybe I'm wrong but one would be reasonable to assume the correct way would be defined in the regional methods manuals. The manuals are clear. The Mehlich 3 is either done by weighing in 2g of soil to 20ml solution and reported in soil mass - mg/kg or by a 2.5cc volume scoop to 25ml solution and reported in soil volume - mg/dm3.
A mineral soil calibrated standard scoop is allowed to weigh in the 2g as a convience to the lab only if it closely approximates 2g of soil. In our container mixes, it isn't close and is clearly a mistake to use a mineral soil calibrated weighing scoop to measure the mass of non-mineral, lighter density soils.
Further explanation on your part with references may clear up the confusion or maybe we will all agree that spectrum, Logan or any lab that measures mass with a wrongly calibrated spoon is selling us garbage?
_tessarecting
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Thanks for chiming in orechron. I'm outa rep.
Biggy,
After some lengthy discussions with the lab guy Vernon, we both agreed that using the wrong amount of reactant on an unweighed soil is not correct. It will give us the right direction, but is not really quantifiable if we want to make numbers, we all agree. But as you saw from what the lab ran, the ratios stay the same regardless of the amount of reactant used.
However, if we do use the weighed 2 grams per 20 ml or whatever, the density issues screw up the calculations. So we really need to know the density by using a scoop and then weighing volume weight to be able to make real numbers.
Sorry, no references to quote.
biggreg
Member
Agreed we need a density to make sense of the soil mass ppm data. Especially for micro limits or growers who want to look at SLAN levels vs Base ratios.
Correctly weighing in the 2g provides the correct calculations for soil mass parts per million. The SERA manual explains the calculation of the units when converting from the amounts detected in solution to soil mass. http://www.clemson.edu/agsrvlb/sera6/MethodsManualFinalSERA6.pdf
Which calculation are you saying that weighing in 2 grams of sample soil would skew due to density issues?
To convert these tests that reportedly tell us the mass of our elements per mass of our airdried soil into a report on the mass of our elements per volume, we need to measure a volume of field ready-moist soil and then take the weight of it airdried in the lab. That would be the relevant units. The test could tell us how many mg per liter of Ca we have in our container.
The decision of Spectrum to only use 1gram scoops and 10ml, I would strongly speculate, has nothing to do with more accurate tests for its customers.
Correctly weighing in the 2g provides the correct calculations for soil mass parts per million. The SERA manual explains the calculation of the units when converting from the amounts detected in solution to soil mass. http://www.clemson.edu/agsrvlb/sera6/MethodsManualFinalSERA6.pdf
Which calculation are you saying that weighing in 2 grams of sample soil would skew due to density issues?
To convert these tests that reportedly tell us the mass of our elements per mass of our airdried soil into a report on the mass of our elements per volume, we need to measure a volume of field ready-moist soil and then take the weight of it airdried in the lab. That would be the relevant units. The test could tell us how many mg per liter of Ca we have in our container.
The decision of Spectrum to only use 1gram scoops and 10ml, I would strongly speculate, has nothing to do with more accurate tests for its customers.
Cannabis line-breeding is the equivalent or pure breed dogs. Reducing the polymorphic nature of an outcrossing species, manipulating the outcomes from matings to increase population density and possibly enhance variation in favourable phenotypes.
Wolves would be the pure breed point that would equate to naturalised indiginous cannabis
biggreg
Member
I grabbed a bag of KIS organic water only with biochar bagged soil. I was going to send a sample of another homemade mix anyway that day for testing so i grabbed a bag out of curiosity.
When I opened the bag, It was stinking of dead fish and was sour/anaerobic. I sent a sample anyway. The lab reported a high ph and I also measured a high ph initially. After leaving the bag open for a week or so, I rechecked it. It smelled earthy and yummy and the ph dropped back down to 6.4.
Please note: the 2g soil sample required for this test was weighed in with a mineral soil calibrated "2g"approximating, 1.7cc volume scoop.
Bulldog, nectar of the gods tests around 80% Ca, 8% Mg and K. K deficiency shows up in that mix pretty quick because it's so light. You can see people on insta that use it don't have flowers that fill out as well as they could. Coots was always around 60-65% Ca, 12-15 Mg and 10-16 K. These are Logan numbers. It's almost always a good candidate for gypsum. FFOF had great numbers only once out of three tests, they probably got lucky on one batch.
Greg those numbers look like a compost analysis.
Greg those numbers look like a compost analysis.
I tested all the Royal Gold soils, mainly Mendo Mix and Basement Mix. They both tested around +/-40% Ca.
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