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Lightweight Peat's Mucky Muck soil testing

biggreg

Member
Update: i asked the lab im working with today to use the USDA Kellogg's lab manual Mehlich 3 standard of 2.5 grams of soil to a 25ml Mechlich 3 solution. No problem, they said.

I was told it is going in the hopper today. Test results soon.
 

biggreg

Member
Once I get a proper lightweight protocol test from these guys, I will ask some of the other labs I've talked with that seem willing for the same. Goal is 2 or 3 labs that will give us the test we need in a proper format.
 

biggreg

Member
Any input from you guys on the format would be appreciated. I'll post the initial report and ask for feedback when I get it.
 

biggreg

Member
For this test which includes an air dried mass/ field moist volume bulk density test (g/cm3) i sent the sample field moist in a sandwich baggie. I poked lots of holes in it so the soil could still breathe and wrapped it in a paper towel. I didn't want it to go anaerobic and screw the ph. I forgot about the holidays and really should have waited to send on a monday but it should be good. Lab received it and it made it fine they said.
 
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biggreg

Member
So, i thought about a side by side with a scoop test but I just can't pay a dime for one of those again.

This sample i sent for this lightweight protocol test was mixed end of last spring and i have a scooped test from 8-5. The lab in this test always measured a higher ph than I measured. Caused me to buy another ph meter to double check myself. They say 6.0 and I say it's been a stable 5.8/5.7 since July1.

The soil i sent Spectrum was a sample of this soil that i titrated a small amount of micronized calcitic lime into to hit ph 6.5* so we can't directly compare to their weigh in test.

If i were a real scientist, my experiments would be more organized. I'm getting there slowly.




This soil has been incubating at room temp out in the garage, kept moist and in breathable containers since that last test.
 
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biggreg

Member
For you Albrecht ratio guys, how do you like to see the CEC summation? The "brookside"/Logan labs method? ( brookside denied this method came from them to me on the phone, wouldn't give out their current method to me and also wasn't interested in weighing my sample with a balance)

Any other methods of CEC summation used by you base cation ratio guys? I want a report everyone, no matter the methodology, can use.

Thinking of not only reporting the elements in mg/kg and mg/dm3 but also in individual Meq.

Ideas? Anyone?
 

biggreg

Member
This lab in New Zealand runs the Mehlich 3 and reports in mg/L. Also a nice tidbit in there on Mehlich 3 extractable Al, good stuff.

What do you guys say, mg/L or mg/dm3? I don't know what's the correct one but per Liter rolls off the tongue nicely. Grams/cubic meter? Kiloliter? Wait, no one uses kiloliter...

cmoles/kg or meq/100g? Cmoles/L? Maybe I'll go straight SI units? Hmmm.

Decisions, decisions...
 

Attachments

  • Mehlich 3 soil test 5565 v2.pdf
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biggreg

Member
For the lime requirement to a target ph chart, I requested the Mehlich buffer. The lab said they were curious so they threw in a Sikora buffer as well for a side by side. We will have a chart of incremental target ph levels and grams of lime per m3 ( or mg/L) requirement.

Anyone have experience using these buffer tests for target ph? I've been titrating my own and never really paid attention to the buffer.
 

biggreg

Member
Some sort of Mehlich 3 calibrated sufficiency levels chart for high demand vegetables is what I asked for to be included. Low, sufficient, high and very high or something like that in relation to the mg/L ppm, not the mass per mass mg/kg ppm.

Plants grow in a volume

I don't have such a chart in mind. I'm sure there are lots of variations out there. I could use some help on this one. The lab agreed but we haven't hashed out the chart yet.

Lots of crop specific Mehlich 3 calibrated ppm levels have been calculated for various soils. I wonder if any field trials on drug strain cannabis have been done. I've seen the hemp ones from Canada but nothing on drug strains. Could use some help here too!
 

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  • Heard_poster.pdf
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biggreg

Member
Want a BCSR friendly report that shows SLAN levels so you can consider both methods at the same time. Big thing is the relevant units.
 

Pangea

Active member
Veteran
Glad I opened this thread.

I sent some samples in to my local lab in '14, and scratched at the rabbit hole that you seem to have dived deep down.

I was posting about effective vs estimated cec back then too, and how our peaty based mixes are not being treated properly by most of the labs available. I kinda threw the towel in quickly with it all.

Im not even sure how to classify my soil, I use peat moss mixed and composted with alfalfa meal, minerals, humates and small amount of clay. The compost is then buffered with a peat/perlite mix at specific ratios.

Ive calculated and self tested my bulk density at 120-125g/L. Ive weighed my peat to 100g/L and have calculated my minerals to be 20-25g/L.

Ive added basic minerals to achieve a calculated ideal BCSR and micro levels, but would like to have a way to monitor and quantify changes over time with new, actively being use and previously used soil.

I use a decent amount of CaCO3 and have had my compost lab tested at 8.1pH, my buffered down actual soil mix lab tested at 7.1pH. I have a bluelab soil pH meter and have had some odd readings, I can test pure peat and new promix HP at 3.5 and 6.5 respectively and then test some of my "in use" soil with various stages and levels of health of plants growing and the average is 7.6 - 8.4pH, with many very healthy plants being at 8.4.

One thing, of the many, I dont understand is with CEC and our peat based soils. Peat has a avg CEC of 100 - 250(meq/L), with added organic matter, clay and humates are analysis results way off and our mixes potentially actually 100ish as they are by calculation?

I feel I dont have a strong enough grasp on the concepts and science regarding soil and soil analysis so mainly like to observe and read what I can, perhaps its a shared feeling and the reason its quite in here.

I do plan to talk to the local "ALS Global" lab here and see if we cant get a proper tests done, they seem amenable and probably not very busy with soil testing in January up here in the prairies.

I am also interested some sort of total mineral test that that can tell me total numbers not concerning availability or potentials, as I start from scratch and have a pretty basic mix it would be interesting to see how accurate my calculations are and to see the before and after numbers on used soil.

Thanks for the posts and the thread and the actual leg work on getting some kind of common ground on the situation!
 

biggreg

Member
I have a bluelab soil pH meter and have had some odd readings,




One thing, of the many, I dont understand is with CEC and our peat based soils. Peat has a avg CEC of 100 - 250(meq/L), with added organic matter, clay and humates are analysis results way off and our mixes potentially actually 100ish as they are by calculation?


I'd classify your soil as an anthropogenic histosol, but I'm not a soil scientist, I just tinker.

Ph readings seem tricky as hell to me. Got 2 of those meters like yours. Try taking some soil and letting it air dry and adding 1:1 distilled water by mass and stir ocassionally letting it sit for 2 or 3 hours. Get 10 matching readings with 2 diffrent calibrated ph meters.

Soil probing it matches that if you are watering with RO or rainwater or something that won't screw your test. Again wait 3 hours after watering. Or do like me and check it OCD style and the real PH will come into focus.

CEC of peat is usually reported in meq/100g (meq/air dried mass) The really fiberous, less broken down peat straight out of the bag measures less. One we mix 1/3 CEC neutral aeration and add other stuff, our density is increased and the CEC of the mix is cut with CEC inert ingredients.

According to a conversation I had with Dr. Tripeppi at U. Idaho, who has been studying CEC of Peat based mixes says they generally are 20 to 30 meq/100g up to 100 meq/100g for well broken down mixes. He stresses that the CEC value per mass is deceptive and the CEC/ volume tells us more

The CEC-7 AA test from the USDA kellog lab manual measured my mix I've been tinkering with at 40 cmoles/kg ( meq/100g). My correctly weighed in Mehlich 3 CEC estimate is about 40 as well depending on how you add it up. The CEC-7 test washes out all salts, free carbonates? and cations, replacing them with NH4. Then the NH4 is counted. ( something like that). I'm confident in it. (On soil with ph less than 7)

Thanks for chiming in. Was feelin' lonely on this street corner protesting lab work by myself.:)!!
 

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  • CEC and CN ratio.PDF
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biggreg

Member
I'm contemplating now on this CEC-7 value and the BCSR method. Both Astera and Solomon in their books say use the " brookside" method of total CEC to add up the cations, exchangeable acidity and other bases to come up with a TCEC. And base ratios off of that.

If I do that with my Spectrum 2g and 6.6ph test results, I over shoot some.(46). I probably have free carbonates in that sample because I sent it in not long after the ph stabilized after adding 1.5g of lime into the 0.2gallon soil sample. (I was playing with home lime requirement tests)

Does anyone know? Is TCEC an attempt to calculate the CEC-7 ?


Any real chemist or agronomist please chime in or even consider taking over this crusade, it's wearing me out.
 

biggreg

Member
Maybe leaching the shit out of a sample with distilled water till no free carbonates exist and send that for a separate CEC-7 test would give the best CEC direct measurement?
 

biggreg

Member
On PH again:

All target PH levels I've seen recommended max out at 6.5 in mineral soil for most garden type stuff you may grow, 6.8 for asparagus.

I've seen no target Ph levels above 6.0 for organic soils.

Target ph for min-organic soils fall between the two.

What's the target ph for cannabis in mineral soil? In organic soil? In min-organic soil?

What are the hydro guys finding to be the optimum ph?
 

biggreg

Member
I'd love to see a kickstarter funded virtual cannabis experimental farm. The farm would have acres and acres of experimental plots, just one container at a time. Independent growers testing soils and plant tissue and running field trials. Sharing data and standardizing methods.

I don't like all this trade secret shit. I don't like mythical stoner magic soil mixes or the woo woo. I'm into finding truth. What's real and how do we measure it? I want to see this shit clearly.
 

biggreg

Member
I don't have many answers on growing but I do have one truth to share:

Sloppy, don't give a shit labs that have never seriously contemplated testing lightweight soils, the McLabs with their mindless, repetitive, monotonous spoon weighing of soils with no regard to correctly classifing basic soil type, achieving or approximating an accurate mass, or reporting the damn thing in relevant units of measure, those labs whose goal is to make maximum profit based on production, not science, whose corporate ethos is greed not a sense of benefiting society, those labs that are willing to send out a report on lightweight soil that is so grossly miscalculated and mis-measured vs the industry standards of precision demanded by "standard" soil farmers, those labs should hang their heads in shame for failing it's customers and should use that shame to fuel new efforts in understanding lightweight soils and mixes and actually strive to help us. Wouldn't that be awesome?

Use your fancy degrees for something, Mr. agronomist! Mr. Chemist! Damn!

I feel zero appreciation for my business just being tolerated and then sent a half assed, fuct-off report.

( just in case no one could tell :) )
 
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biggreg

Member


The usda kellog lab methods manual is some great reading!

This CEC-7 test gives a pretty solid direct measure of "total"'CEC on most soils

Thinking if I'm experimenting with BCSR, I'll base it off the CEC-7 test and double check against the Mehlich 3.

Google USDA Kellog 5.0 manual or look back in this thread for a link
 

biggreg

Member
My CEC-7 test was done by U. Idaho. They laughed when i asked about scoops. They said no scoops are ever used in their lab. Just takes too long with those guys as they have a research workload. They accommodated me, letting me slide into Dr T's research. Got the effective CEC barium test( 33 cmoles/kg @ 5.7ph and 40 cmoles/kg @7.0 with the CEC-7.
 
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