Lightweight Peat's Mucky Muck soil testing

[biggreg]

Same north central manual on a Monocalcium Phosphate Sulfur extraction requiring an actual mass measurement for peat or muck with a slightly differing procedure:

"
1. Pass air-dried soil through a 10-mesh sieve.

2a.Mineral soils: Scoop 10 g of dried, crushed (10-mesh) soil into 50 mL Erlenmeyer flasks.

2b. Peats and mucks: Due to the high water holding capacity of organic soils, 50 mL of extracting solution must be used. (see Pro- cedure, paragraph 3, below). Therefore, record the weight of organic soil delivered by the 10 g scoop. The extra dilution from the 50 mL of extracting solution will require doubling the S reading obtained from the standard curve. To allow for the low bulk density of organic soils, record the weight of soil delivered in the 10 g scoop. Then multi- ply the calculated “ppm in soil” (see Step 6 in the determination procedure) by 10 g per actual weight."

Peaty soil know how is already in their manuals and textbooks. Nothing new has to be forged. We just need labs that know their shit, that's all.

 

[biggreg]

How about some north eastern standards?
2.5g to 25ml

From their manual:
"Note:
The original procedure of Mehlich (Mehlich, 1984) calls for maintaining a 10:1 solution:soil ratio on a volumetric basis (i.e. 25 mL Mehlich 3 solution to 2.5 cm3 soil). However, many laboratories that switched to the Mehlich 3 from other test procedures developed their calibration database on soils extracted with a 10:1 solution: soil ratio on a weight instead of a volume basis (i.e. 25 mL Mehlich 3 solution to 2.5 g of soil or 20 mL of Mehlich 3 solution to 2.0 g of soil). The current recommended procedure for Mehlich 3 for laboratories in the North Central region is to maintain a 10:1 solution:soil ratio on a weight basis (Knudsen and Beegle, 1996). Peforming the procedure by either the weight of volume method is appropriate so long as the calibration database upon which the recommendations are based was developed using the method selected."

The weight basis is needed to align this test with other tests that are all measured on a per weight basis as well.

Larger sample sizes are better than smaller ones. Why choose less than the gold standard 2.5g / 25ml?

 

[biggreg]

And from the USDA Kellog lab manual for the Mehlich 3:

"7.1 Weigh 2.5 g of <2-mm or fine -grind, air-dry soil to the nearest mg into a 50- mL centrifuge tube. If sample is moist, weigh enough soil to achieve ≈2.5 g of air-dry soil.

7.2 Dispense 25.0 mL of extracting solution to the tube."

Interesting they have a moist soil option.

 

[biggreg]

Have I made the case that peaty soil's mass should be measured in with a balance and not a mineral soil density calibrated volume scoop?

Have I made the case that a measured bulk density is required to convert the per dry mass results of the test to useful, relevant, per volume units?

I will keep going if it's unclear.

 

[Bradley_Danks]

Have I made the case that peaty soil's mass should be measured in with a balance and not a mineral soil density calibrated volume scoop?

Have I made the case that a measured bulk density is required to convert the per dry mass results of the test to useful, relevant, per volume units?

I will keep going if it's unclear.

Its about as clear as its gonna get for now. I'm out of my realm here but trying to learn more about lab testing soils. Thanks for trying to explain everything with so much depth.

Most of the native soil around my parts is called Jory. https://en.m.wikipedia.org/wiki/Jory_(soil)

What's your thoughts on jory soil?

 

[biggreg]

What's your thoughts on jory soil?

Thanks.

Jory is an moderately acidic red volcanic basalt derived silty clay loam that produces some damn good wine grapes, I hear.

It's high in iron and that clay probably needs organic matter to loosen it up for gardening.

You planning an outdoor garden? If so, don't be afraid of the soil scoop. It will measure the mass of your Jory sample close enough. Get a test, they are relatively inexpensive

 

[biggreg]

When you test this Jory soil with the Mehlich 3, its easy to get an accurate sample mass measurement and a report in relevant units. The soil test industry is great at it. It's what they do.

The standard soil scoop measures the sample mass close enough in mineral soil.

The per dry mass result of the test of this Jory soil in mg/kg ppm, converts to relevant per volume units of field moist with the simple bulk density assumption of 1.

No measurement of bulk density is required. It's safe enough to assume it's close enough to 1g/cm3 or 2mill lbs/ acre slice.

I'm happy with a scooped mineral soil test all day long. It has already exactly what I'm calling for in a lighter weight density soil test: Accurate sample mass and a report in relevant units!!

 

[Bradley_Danks]

Yep, I'm planning on expanding the current garden. I had a soil test done using an aaph7. I'll post it here so you can see it. Its from a&l western in Portland, Oregon. Feel free to share your thoughts on the test results.

What do you think the accuracy is? The lab always asked me if it was native soil or a container media I was testing. They said they used separate tests for the two types.

Here's last years garden:

I want to add about 20 more plants. We did four there last year.

 

[biggreg]

Feel free to share your thoughts on the test results


What do you think the accuracy is?

I would guess the accuracy is within allowable industry tolerances. It's only the lighter density soils that labs aren't paying attention to the sample mass.


I'm not the one to ask on soil reccomendations but if I had this soil with this test, I'd follow their reccomendations and would use calcitic lime not dolomite in this clay soil. You need the ph above 6 in mineral soil for nutrient availability Maybe ph 6.4/5 would be optimum.

 

[biggreg]

I noticed the A&L recommendations are for good ol' "tomatoes".

I wonder who will be the first lab to step up and offer recommendations for cannabis?

Are there any labs out there already offering cannabis as a crop choice to base fertilizer guidance on?

 

[jidoka]

Yep, I'm planning on expanding the current garden. I had a soil test done using an aaph7. I'll post it here so you can see it. Its from a&l western in Portland, Oregon. Feel free to share your thoughts on the test results.

View Image

What do you think the accuracy is? The lab always asked me if it was native soil or a container media I was testing. They said they used separate tests for the two types.

Here's last years garden:

View Image
View Image

I want to add about 20 more plants. We did four there last year.

I personally like to see Ca ppm about 10x both K and Mg

Tomato needs a little higher K in flower than mj due to the fact it is making more sugar than the bud of mj. Other than that they are pretty close.

 

[orechron]

Bradley, you're in my area. That soil will work fine if you get calcium up to 70% base saturation minimum. I used to use A&L but they will only run dpta on "medias" not mehlich 3. I can't really make calls on amendments with just dpta.

 

[slownickel]

Bradley,

Running AA@pH 7 on an acid soil doesn't make much sense....

 

[biggreg]

Bradley,

At a ph of 5.2 in undistrubed, never limed Jory, there should be zero free Calcium unless my understanding is flawed.

This is from the western region methods manual.

"EXTRACTABLE POTASSIUM, CALCIUM, MAGNESIUM, AND SODIUM S - 5.10

Ammonium Acetate Method

Scope and Application

This method semiquantitatively determines the amount of soil plant available K, Ca, Mg, and Na residing on the soil colloid exchange sites by displacement with ammonium acetate solution buffered to pH 7.0. Cation concentrations are determined using atomic emission (AES), absorption spectrometry (AAS) or ICP-AES instrumentation. A chemical interference solution is used to minimize chemical matrix effects. It is based on a modification of the procedure outlined by Knudsen et al. (1982) for exchangeable K. Generally, these cations are associated with the exchange sites. The exception are soils that have high soluble salts and are saline, which requires a special preanalysis treatment. The method doesn't correct for calcium and magnesium extracted as free carbonates or gypsum. In the northern Great Plains the method has been used to determine available sulfur. The method detection limit is approximately of 25 mg kg-1 (on a dry soil basis) and is generally reproducible ± 7%."

From the comments on the procedure:

"Soils high in soluble salts (ECe > 1 dS m-1) should be washed with deionized water before adding extraction with ammonium acetate to reduce potential errors of soluble salts. This can be accomplished by adding 50 mL of deionized water to 2.5 g of soil, placed in a 50 mL centrifuge tube and centrifuge at 5000 rpm for thirty (30) minutes and decanting excess water followed by the standard analysis protocol. For soils having pH > 7.4 and calcium carbonate> 0.5%, should be extracted with ammonium acetate pH 8.5 to avoid the dissolution of calcium carbonate."

 

[biggreg]

Mehlich 3 isn't common in the labs of the western states, I've found. .It displaces cations in a very similar way to AA but has the advantage of extracting anions and micros at the same time. It has similar interferences listed as the AA7.0

Neither are good for alkaline soils. The AA8.2/8.5 should be used for the cations in alkaline soils

Maybe Slownickel has real world experience that differs from the manuals?

 

[biggreg]

Bradley,

Labs in the Western states region rarely use the Mehlich 3 for cation extraction. It is sometimes used for a Phosphorous extraction there.

The western region has what one argonomist described to me as "wacky soils". The AA7.0 and 8.5 are the main choices of labs in this region. The AA8.5 typically used for the alkaline soils. The Mehlich 3 cation extraction would be a special request for labs in this region judging by the responses to my nationwide lab quest.

The "standard soil scoop" isn't in the western region manual. Labs in these states weigh everything with a balance to my knowledge. That is a plus for accuracy concerns.

If you want to try to balance minerals Albrecht style vs the SLAN charts, it seems the Mehlich 3 is the more popular test for those using that methodology of balancing the base cations, anions and micros into ideal ratios.

The AA 7.0 Cation extraction should produce about the same values as the Mehlich 3 for base cations in acidic soils that have not been recently limed or amended, as both tests displace the cations in similar fashion with ammonium.

But

The weak Bray for P and DTPA vaules for your micros in ppm will somewhat index with but not match the Mehlich 3 ppm values. All these tests are indexed to plant response but can have their own numerical value ranges.

I not aware of a Albrecht style offshoot that balances anions and micros with anything other than the Mehlich 3. I'd love to see an alternative scheme. ?????

Otherwise if you use the SLAN chart from that lab, The target for max yield would be to have all the elements on that bar graph just touching the bottom of the high range.

Good luck!

 

[Bradley_Danks]

I personally like to see Ca ppm about 10x both K and Mg

Tomato needs a little higher K in flower than mj due to the fact it is making more sugar than the bud of mj. Other than that they are pretty close.

Interesting, I'll keep that in mind. I added some limestone last year. I'm working on getting an updated soil sample tested now.

Bradley,

Running AA@pH 7 on an acid soil doesn't make much sense....

Those rascals at the lab probably know that too but give no shits. They told me they can't give recs on marijuana because they don't have enough data on it yet since its such a new legal crop.

Bradley,

Labs in the Western states region rarely use the Mehlich 3 for cation extraction. It is sometimes used for a Phosphorous extraction there.

The western region has what one argonomist described to me as "wacky soils". The AA7.0 and 8.5 are the main choices of labs in this region. The AA8.5 typically used for the alkaline soils. The Mehlich 3 cation extraction would be a special request for labs in this region judging by the responses to my nationwide lab quest.

The "standard soil scoop" isn't in the western region manual. Labs in these states weigh everything with a balance to my knowledge. That is a plus for accuracy concerns.

Good luck!

That's odd that things are the way they are. I'm glad your helping me see what's really going on. This is confusing as hell for us folks just trying to learn. I'm going to get a melich 3 test and an aaph 8.5 test it looks like that will get me on track to dialing things in.


I took a soil sample a few days ago. Once I get it dried and sifted I'll send it in.

Thanks for the luck I'll need it

 

[slownickel]

Mehlich 3 isn't common in the labs of the western states, I've found. .It displaces cations in a very similar way to AA but has the advantage of extracting anions and micros at the same time. It has similar interferences listed as the AA7.0

Neither are good for alkaline soils. The AA8.2/8.5 should be used for the cations in alkaline soils

Maybe Slownickel has real world experience that differs from the manuals?

Yes, very different experience.

When working in acid soils I learned about metal toxicities on some of the most washed out red clays on the planet. (Costa Rica is number 1 in the world for stomach cancer, long story).

There I learned from a local professor about metal balancing to lower aluminum toxicity.

When I came to Peru and started working on alkaline soils, here too there was aluminum toxicity, but for a different reason, bicarbonate reactions in the soil.

When using the local saturated paste, AA@pH 7, etc... metal levels were ALL reported low. They didn't even test for aluminum. Not supposed to happen. Often iron was dominated by manganese, yet iron off the chart on the leaf analysis.

In an alkaline soil, we have more cations than the natural capacity of the soil to bind those cations. This is why the pH is higher. Don't let pH confuse you. When trying to use any other procedure other than M3 we never saw Fe toxicity of 200 ppms or more. All other procedures would report silly low numbers. Yet, when we finally test Al, often Al was higher than Fe and Mn together!

Took me years to discover the reason that Al was toxic in an alkaline soil. Didn't mean it wasn't true, just means I didn't know how to explain it.

When I started treating the metal issues in Peru, half of our yield increases in nearly every crop were because of metal balancing.

Back in 1999 when I first started here in Peru, they would import 4 tons per year of Manganese sulfate. Now a days they import 40 tons to 50 tons per MONTH.... sometimes more!

The only way you can balance an element is to know what is there. Measuring elements at a pH of 7 is testing nearly water soluble elements.

Roots exude organic acids in the realm of 3.5 to 4.5 pH.

That is the pH I want my metals reported at. And even then, lengthen the shake times!

Try it side by side, learn. That is how I figured it out.

 

[biggreg]

Bradley,

Running AA@pH 7 on an acid soil doesn't make much sense....

Wondering if you mis-spoke or have direct knowledge on this?

I'm having trouble referencing your statement with any listed interference from any of the 4 regional methods manuals or the usda manual.


What is it about acidic soils that interfere with the AA7.0 cation displacement?

Help us.

 

[biggreg]

So on acid soils you're saying with direct experience that the M3 and AA7.0 do not jive on Ca, mg, K and N. when ran side by side?



The AA7.0 isn't used to test for all the other elements you mention.