Lightweight Peat's Mucky Muck soil testing

[biggreg]

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.

 

[biggreg]

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!

 

[biggreg]

I think the lesson were learning is don't *uck with labs that don't know organic soils.

Our peaty recycled container soils have more in common with muck farming than container media. Were more broken down. Worm castings, maybe humate ore. These ain't just a inert root media like some pro-mix. We grow in real damn soil. Two main divisions of soil on this earth, organic soil and mineral soil. The labs know it. The freaking info I've been posting on the diffrences between the two types comes off these labs websites!


Jidoka, did you see the sample NCDA Original Mechlich volumetric style report I put up? You can balance your Albrecht in meq/cm3. I think the report should be in a similar format.

 

[biggreg]

Labs that run the same test should get the same results within the accepted tolerances of the test. The NAPT program oversees lab profiency. They exchange soils with known values with these labs and grade them. If labs don't follow the standard is where we get problems. On the practice of a 1g weigh in vs the 2g weigh in from the NAPT guy:

"I tossed your question to our NAPT oversight committee chair, Tony Provin at Texas A&M who does a lot of M3 in their lab. I've included his response below. Given the fact that the higher mass sample provides greater error control and provides sufficient sample for analysis (esp for low density, high porosity material like yours) then I say you have reason to request they re-do your samples--even if many labs are currently using 1 gram samples.

There is reason, in fact, behind the published standard procedures from our regional soil test committees. They are tried and true protocols. When we evaluate a lab's performance, it is assumed they are using the procedure as published. The labs run the risk of poor performance in comparison to their peer labs if they modify things too much. Perhaps you should request to see their NAPT performance reports for the last several quarters to assure yourself that they are doing well in general on M3 analysis. We are not free to share their data with you.

Hope that helps.

Grant"

 

[biggreg]

"Grant

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.

Our lab uses the 2 gram sample, which is largely required for our state with the true sand texture to 60% clay soils, just to have enough sample to run on an ICP.

Tony

From: NAPT"

 

[biggreg]

"This is really interesting to me. I will be attending a couple of the regional soil test committee meetings in the next few months and plan to have a number of discussions on this issue. If you're ok with it, I'd like to use your example as a discussion point.

Grant "

 

[biggreg]

I don't mind if a lab is ignorant if they admit to it. It's when they try to bullshit me that really gets me going.

 

[VortexPower420]

I think a few of you guys are going to chage how they do soil test as a whole.

Looks like some labs were getting lazy.

Thanks for the investigation and follow through.

 

[biggreg]

My thought is we should all put our heads together and come up with a proposed standard protocol and a report that makes sense for our soils and find at least 3 or 4 labs that will work with us.

I'm tired of looking at meaningless bar graphs that say our soils are off the charts on elements. Our soils may hold more elements per Kg than mineral soils but it's per volume that counts. Bulk density should be a standard and those bar graphs should be tied to mg/l. Then they would mean something.

 

[acespicoli]

biggreg

I was looking into this,

Recommended Method for Crushing and Sieving Soils
Because soil is defined as having a particle size of less than 2 mm, this sieve size (10
mesh) is recommended for routine soil testing. Various soil grinders and crushers are available
commercially and are typically large, motorized, mortar and pestles, hammer-mills, or rollercrushers.
The amount of coarse fragments common in some samples limits the use of some of
these. In general, it is desirable to get most of the sample to less than 2 mm with the least
amount of grinding. If the sample is to be analyzed for micronutrients, all contact with metal
surfaces should be avoided during the crushing and sieving procedures unless it has been clearly
demonstrated that the metal is not a source of contamination.
Cross-contamination between samples can be avoided by minimizing soil-particle
carryover on the crushing and sieving apparatus. For macronutrient analysis, removal of particles
by brushing or jarring should be adequate. If micronutrient or trace element analysis is to be
performed, a more thorough cleaning of apparatus by brushing or wiping between samples may
be required.
***************************************************************
Grain size is classified as clay if the particle diameter is <0.002 mm,
as silt if it is between 0.002 mm and 0.06 mm,
or as sand if it is between 0.06 mm and 2 mm.
Soil texture refers to the relative proportions of sand, silt, and clay particle sizes,
irrespective of chemical or mineralogical composition.
***************************************************************
two different particle-size sphagnum peats, a fine one (0–10 mm) and a coarse one (20–40 mm).

 

[biggreg]

Labs usually grind and pass it through that sieve. I've heard of others requesting no grind. My thought is just stay with the written standard so we are all looking at the same test. I don't think a grind like that would micronize anything. But i don't know. A no grind scoop test would be awful and would test even less soil than the ground scoop test.


I've looked into micronizer grinders to grind down some of this glacial till we have here in AK. Those grinders are pretty serious to micronize something.

We got 2 totally geologicaly different mountain ranges with 2 glacial rivers emptying into this valley. Lots of minerals'to harvest!

 

[acespicoli]

Im definitely learning more than I knew before glad I didn't send that lab test out yet!

Calculations Soil volume

Soil volume = ring volume
To calculate the volume of the ring:
i. Measure the height of the ring with the ruler in cm to the nearest mm.
ii. Measure the diameter of the ring and halve this value to get the radius®.
iii. Ring volume (cm3) = 3.14 x r2 x ring height.
If the ring diameter = 7 cm and ring height = 10 cm Ring volume = 3.14 x 3.5 x 3.5 x 10 = 384.65 cm3

Dry soil weight

To calculate the dry weight of the soil:
i. Weigh an ovenproof container in grams (W1).
ii. Carefully remove the all soil from the bag into the container. Dry the soil for 10 minutes in the microwave, or for 2 hours in a conventional oven at 105ºC.
iii. When the soil is dry weigh the sample on the scales (W2).
iv. Dry soil weight (g) = W2 – W1

Bulk density

Bulk density (g/cm3) = Dry soil weight (g) / Soil volume (cm3)

Bulk density is usually expressed in megagrams per cubic metre (Mg/m3)
but the numerically equivalent units of g/cm3 and t/m3 are also used (1 Mg/m3 = 1 g/cm3 = 1 t/m3) (Cresswell and Hamilton, 2002).

 

[biggreg]

Don't microwave or oven dry a sample that's to be tested. Screws with the results.

Here is an issue. These extraction tests call for air dried soil. The labs use a low temp oven or a desiccant drying system to air dry the soil. There is a difference in weight between air dry and oven dry. If i measure my bulk density at home, my oven dry weight will be lighter than the labs air dry weight. If i air dry at home, will the moisture content be the same as the lab's air dried sample? Want apples to apples, ya know?

I'd love it if the Lab had a good method of bulk density measurement for our type soil. Should be a standard on organic soils.

 

[biggreg]

Michigan state has differing vegetable production reccomendations for mineral and organic soils.

They aren't using the Mehlich 3 so the numbers won't quite match up but I'm just posting it to illustrate the point of this thread, the diffrences in organic, lightweight, peaty soils vs mineral soil.

 

[biggreg]

In North Carolina, another state with peat soils under vegetable production, The NCDA, as a standard, tests bulk density and performs the Mehlich humic matter test to determine if the soil is mineral, mineral-organic or organic. Dr. Mehlich left his mark on that state. They do the Mehlich buffer lime test, mehlich's humic matter test and the Mehlich 3 in the Mehlich original volumetric style of a 2.5cc scoop and 25ml solution. The results of a NCDA test is reported in an index system that confuses me but can be converted back to mg/l.

In these states, labs recognize the diffrences in peaty soils vs mineral and have differing reccomendations. Both use volumetric reporting appropriate for the large variations of bulk densities of soil in those states.

 

[biggreg]

As i look over all the diffrences in organic vs mineral soils, i wonder if any of the base cation ratios guys have ever actually looked seriously at organic soils? Has anyone heard of any research on organic soils in the Albrecht papers? Any other researcher's papers? Anywhere?

With humic matter's differing chemical properties vs the clay in mineral soils, its differing affinities and fixations of the elements vs the clay in mineral soils and its differing physical structure vs mineral soils, do mineral soil ideal ratios apply to organic soils? Will more magnesium really tighten up a fibourous peat and compost based soil? Or it that just true with mineral soils with clay?

 

[biggreg]

And after going through all this info, I have never grown in low ph soils like the reccomended target ph in those organic soils guides. 5.3? 5.5? 5.8?.

Does anyone grow our plant in this ph? I have always used 6.3 as a target. Don't remember where i got that when I first started growing but I've never looked into it again until now.

 

[biggreg]

More diffrences between our recycled organic soil container mix testing and mineral soil testing: Time required after applying amendments before retesting.

Mineral soils generally are amended either in the fall or spring. Recent liming can distort extraction tests that will pick up free calcium un-attached to the exchange sites. The time required for all the lime to react and attach itself to the exchange sites is dependent on variables such as soil temp, rainfall or watering, lime quality, lime particle size and evenness of distribution. Maybe 6 months to a couple years to fully incorporate in those soils.

In our soils we generally use high quality micronized lime. Our mixing and distribution of the lime into the soil is much more uniform than plowing it into a field. So how long should we wait after a re-amend to test? Our variables that influence the answer are also temp and moisture related. Assume we incubate our soils at garden conditions after a re-amend using micronized powder amendments that have been pre- "cooking" in some compost and/or humates and we have robust soil life. How long before the amendments "settle in" and become stable enough for a good test? Ph stability is one measure of readiness.

What do you think? 3 weeks min assuming ideal conditions? 4 weeks? 6 weeks? It's definitely less than what's needed out in the field.

Whatever the answer is, if we don't wait long enough, the test will be garbage.

 

[jidoka]

i have grown in a peat soil at a pH of 5.9. but eventually i switched to mineral soil. there is so much more good info

thinking about it now i would load organic soil with enough vansil to hit a pH of 6 and then feed the rest with salts...and i would test it every grow to hold it at 6.

outdoors you aint gonna catch me running an organic soil period

 

[biggreg]

i have grown in a peat soil at a pH of 5.9. but eventually i switched to mineral soil. there is so much more good info

You got that right. Organic soil research is harder to come by.

Knew a girl once who used vansil on her flower garden. It worked, she said, No more itching or burning