# G-man Soil Tests Experiment



## g-man (Jun 15, 2017)

This year I wanted to explore different labs than Logan Lab. Mainly I wanted more transparency in the report (what test methods are used) and a clear view on how to address any soil issue.

_Approach:_
- I sampled my soil as the same method I've used in the past. Multiple samples (+20) across the yard. 
- I placed them in a bag an mixed it all up. The bag was sealed and stayed in my garage for a month (no time to send the samples)
- I mixed it again and divided into equal parts. I did my best to ensure it was mixed.

_Test site:_
I sent the sample to Logan Lab ($25), Waypoint TN ($16.50) and A&L Great Lakes (I chose the complete test $30 instead of $20). I wanted to include PSU too, but I did not collect enough soil. In hindsight I should have also done Soil Savvy. 
They all call for credit card info and sent the results via pdf. Waypoint includes a service that they will keep track of your soil and trends for free. I have not tried it yet.

_2017 applications:_
5.67lb P205 /M
4.67lb K2O/M
Always returned my clippings

_Results:_


I took the previous data I had plus the reports and converted them to ppm, so I could compare them. Yes, there is something going on with my phosphorus. More importantly, each lab reported a different number. A&L used Bray-1 Equiv, Waypoint used M3 and Logan I don't know. Waypoint looks to report a higher sulfur and A&L a lower iron. Everything else with them looks about the same. I sent an email today to Waypoint for an explanation of why the use of the M3 test is acceptable given my 8.1pH.

_Conclusion_
The main thing to me, and I hope to most members is the recommendations. Both A&L and Waypoint recommendations look similar and on par with what I would normally do. I need continue to add more phosphorous and potassium. Waypoint seems easier to understand and it is half the price than A&L.

Therefore I will like to highlight that the lab used for the test is important. In general you want a test that provides clear results with a guide on what to apply for the year. Doing yearly reports with the same lab, using the same test methods and the same sampling method will provide you with a trend of your soil. This links will help you in find a local lab that knows your state typical soil/test methods. Ridgerunner links to soil test sites: http://www.naptprogram.org/about/participants/all/ or search by State or Province: http://www.naptprogram.org/about/participants

8am Edit: It was late last night and I forgot to mention one last item. While I have a high pH, low P and low K, I still have a thriving lawn with no major issues. Last year I had some dollar spot but no other fungus. You could see images of my lawn in 2018 Cool Season Lawn Pictures. Addressing soil issues is important, but patience and following the general practices from the site will yield a decent lawn.

_Reports:_


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## 440mag (Jan 29, 2018)

I'm still trying to absorb it all; however; one thing is immediate: Gratitude!

Thanks gman for setting this up!!!!!!!!!


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## Ridgerunner (May 16, 2017)

Thank you @g-man .
Great research resource! It's late and I may be going out of town tomorrow, but when I get some time I'll try to give an explanation of why what occurred, but pH is the yin and the yang.


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## social port (Jun 19, 2017)

What a great idea. Thanks for posting this.



g-man said:


> Doing yearly reports with the same lab, using the same test methods and the same sampling method will provide you with a trend of your soil.


That strikes me as so sound. I've never considered how that level of consistency would be advantageous, but it makes so much sense.


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## J_nick (Jan 28, 2017)

I was just thinking earlier today " I wonder if g-man has got all those soil tests back yet" and now I have my answer :mrgreen:

Any idea why your phosphorus is so inconsistent?


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## g-man (Jun 15, 2017)

I got the last test result yesterday, so I need some time to digest that part. A few thing in my mind to research:

- The soil sat for a month in a seal bag in the garage before testing. Could that affect it?
- All 3 labs showed low P values, even when using different test methods, so could the 2017 value be incorrect?

One thing I going to do differently is to use Ammonium Sulfate exclusively to help with the pH.


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## desirous (Dec 15, 2017)

g-man said:


> - I sampled my soil as the same method I've used in the past. Multiple samples (+20) across the yard.


@g-man, can you share more about the sampling method? I notice the Logan report indicates 6". Did you use the whole 6" (depth 0-6), or only part of it?

As P travels down the soil extremely slowly, anything added in the last year would only be present in the top portion of the sample.


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## g-man (Jun 15, 2017)

That wasnt clear. I used the andy method (also described in PSU), I took the inch of soil from 3in-4in of soil this year and in previous years. Logans this year reported the 6 in (even after writing 4in). I converted it all to ppm to have a common number to look at.


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## Virginiagal (Apr 24, 2017)

Can you find a lab that uses Olsen? That might be the best for getting a useful P measurement. See this link:
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_051918.pdf&ved=2ahUKEwjgia2T_9faAhUC7oMKHaajD-wQFjABegQIBxAB&usg=AOvVaw2jveO4_zFydgVneVKjsyPN


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## social port (Jun 19, 2017)

@Virginiagal Great to see you again


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## g-man (Jun 15, 2017)

I had an email exchange with Waypoint. I originally asked them why they used the M3 for the P when the pH was high. They highlighted that the offer a test for alkaline soils (SW1). It is not listed in the homeowner section, but it shows in the agricultural soil section. It does:

pH, buffer pH, Organic matter, CEC, % Cation saturations
Olsen P
Ammonium Acetate (K, Mg, Ca, Na)
Mehlich 3 (P, B, S, Fe, Mn, Cu, Zn)

He also indicated that the M3 test closely matches the Olsen test. I found this report that shows an r=81 between M3 and Olsen on calcereous soils. The link Virginiagal posted above, recommends the Olsen test and other reports I found online. In the future I will request the SW1 report from waypoint.

This still doesnt explain why the P is low, given that it was reported higher in 2017.


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## Ridgerunner (May 16, 2017)

g-man, you've exposed the soft underbelly of soil testing.  
VG has cited a very good overview of the P extraction methods. All three of the labs used here employed M3 for extracting all of the reported nutrient values with the exception of A&L, which uses Bray P1 for the extraction of phosphorous instead of M3. Numerous studies have determined that M3 extraction is very well correlated to soil nutrient levels and is an accurate method of nutrient measurement for soils with a pH of 7 or less (many soil specialists believe useful results can be derived using M3 in soils with pH as high as 7.2 or even 7.4). 
The soil test extraction solutions used for M3, M1, Bray P1, and Bray P2 are acidic with a pH of around 2.5. At that pH, the pH of a soil with a pH below 7 has negligible impact on the "acidic strength" of the solution and the amount of nutrients that get extracted. However, in soils with a pH higher than 7, the carbonates and bicarbonates within the soil have an increasingly and highly variable effect on the strength of the extraction solution that results in neutralizing the solution's pH, weakening the solution which can drastically affect the ability of the solution to extract nutrients with unpredictable results. Consequently, employing these extraction methods in higher pH soils (especially in soils with a pH of near 8 or higher) make for very unreliable/i.e. useless results. Where soil pH is high, the Olsen extraction solution (Sodium bicarbonate, pH 8.5) for phosphorous, an ammonium acetate extraction solution for the Base Cations (Ca, Mg, K and Na) and DTPA extraction for micro-nutrients should/must be used for accurate/usable results.


> Therefore I will like to highlight that the lab used for the test is important. In general you want a test that provides clear results with a guide on what to apply for the year. Doing yearly reports with the same lab, using the same test methods and the same sampling method will provide you with a trend of your soil.


Excellent advice and it does lead to a caveat to what I just wrote. A number of specialists have stated that M3 extraction of phosphorous will provide usable P (and micros) values even in higher pH soils. It is possible that using the same lab (with the same year to year internal controls) might provide enough consistency to result in usable P levels for comparison and amendment, but I am not so convinced.


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## Virginiagal (Apr 24, 2017)

Does Waypoint still have your sample? Can they run the SWI on it? I would be interested if their fertilizer recommendations change or stay the same.

As for why Logan in 2017 had a higher P number than it did in 2016 or 2018, maybe you just happened to get soil that had more P or you got it before it had gotten fixed to calcium. Fixation is a problem with high pH soil. You might have lots of P but it binds fairly quickly to calcium in a high pH environment and then is not available. Also soil tests are not going to measure organic P which could be ample and held in various soil organisms and dead matter. Thanks go to the mycorrhizae which do such a good job of seeking out P and getting it to the plant. It's a balancing act to use enough fertilizer with P if you are low and really need it without discouraging the mycorrhizae.


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## ChappyEight (May 9, 2018)

Is this the form you used, @g-man? http://www.waypointanalytical.com/Docs/samplesubmittalforms/WaypointTurfInformationSheet-Tennessee.pdf


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## g-man (Jun 15, 2017)

Yes. Ask for the SW1. Write your phone number and email in the boxes. They will call your for payment (credit card) and email you the results.


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## ChappyEight (May 9, 2018)

Just for my own curiosity, any reason you chose the Texas/Southwestern US (SW1) test instead of the Eastern US Homeowners & Landscapers (S3M) test? I'm guessing because the SW1 includes the Olsen P? Everything else seems the same.

Again, just for my own learning purposes.


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## g-man (Jun 15, 2017)

Yes. For alkaline soils, they recommended me the SW1. Most Indy soils are alkaline. The SW1 does the same test as the SM3 plus the Olsen P and ammonium acetate. The last two benefit alkaline soils. Is you lt soil ends up not being alkaline, then next year do the SM3. It is only $10 more.


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## ChappyEight (May 9, 2018)

Gotcha. Thanks for the clarification. Ordering the SW1 right now. Looks like I should use this form instead, yes?


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## SJ Lawn (May 7, 2018)

g-man said:


> Yes. Ask for the SW1. Write your phone number and email in the boxes. They will call your for payment (credit card) and email you the results.


I see the website does not list prices.

$ 16.50 is the total price you paid for the Waypoint test results you posted above ? I was going to send a sample to Penn State, but noticed OM and mircos are not part of the $ 9.00 test.


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## g-man (Jun 15, 2017)

They don't state their prices online, only over the phone. The SM3 is $16.50 (a month ago)and the SW1 was $26.50 (a month ago). If you suspect an alkaline, go for the sw1.


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## ChappyEight (May 9, 2018)

@g-man, do you suggest individual sample bags for both front and back yards? Or do you suggest combining all cores into one large "whole lawn" sample?


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## g-man (Jun 15, 2017)

Up to you and your budget. My first time I did it split because it was a new house construction (sod front and seed back), but it was not a significant difference.


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## kur1j (Jul 2, 2017)

I just sent in a soil sample to Waypoint today. The last 2 tests I've done I've gotten back a Ph of 6.4 and 5.9. Based on this I selected the S3M test and the "Texture". From my understanding, the "Texture" is something I would only need to do once correct? Are there any other tests that I should also have them run that aren't included in the S3M and the Texture?

Also every single test I've ever gotten back show that I'm low on all macro and micronutrients. The test I did in the spring/early summer last year (Soil Savy) said to apply .75lbs/1k of 16-16-16. It said my P was .29ppm and my K was 11.17ppm. I applied 19-19-19 at 1lb/1k every month and did another soil test at the end of the year (Sept). This one came back with a recommendation of 1.95lb/1k for P and 1.61lb/1k K. They gave the P and K numbers in lbs/acre which were 6 L and 72M respectively.

Should I be dumping a lot more fertilizer than 1lb/1k? From my understanding, the soil we have is pretty acidic. The lawn company that was doing it for the first year of the home was putting out Lyme every fall to raise the Ph. The only thing I really know about this soil is that it holds moisture well, but does not hold nutrients well at all. Is that accurate and what I'm seeing here?

@Ridgerunner Continuation of our conversation. Thought it might be more appropriate since I'm just talking about soil testing.


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## g-man (Jun 15, 2017)

Yes, I would do the S3M. Don't over think it. Wait for the results and follow their recommendations. Have you applied anything to the soil in last two months? (Lime, P or K)

Texture should tell you the composition of your soil (Sandy, clay, loam). It is a nice to know and do it only once. It wont change over time.


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## kur1j (Jul 2, 2017)

@g-man Thanks. Fair enough. Since the test lyme has been applied not sure how much. .5lb/1k of 19-19-19 at end of april and then 1lb/1ksft of N, of 24-0-11 40% slow release 6% iron end of May.


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