# McKinneyLawn soil test



## MckinneyLawn (Apr 20, 2018)

I wanted to share my soil test to see what advice that y'all might have. I have really high pH which is caused by my calcareous clay. That clay also is why my calcium is through the roof. As far as the rest of the nutrients go I think I'm alright except for Magnesium, Iron in the back, and Potassium in the front. I did hit both yards last year with sulfur (can't remember how much). Thanks for your advice!


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## Ridgerunner (May 16, 2017)

Personally, I'd consider those results to be sufficiently within sufficiency ranges (banked) to just start applying maintenance levels of fertilizer. (See my soil test thread section for The Simple Method/MLSN. see turfhacker link) That is, applying what the turf plant will remove from the soil. Apply 0.2#/M of P2O5 and [email protected]/M of K2O for every pound of N/M you feed the lawn this year.


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## MckinneyLawn (Apr 20, 2018)

Thanks Ridgerunner


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## Ridgerunner (May 16, 2017)

NP. Thanks for posting, it's given me a chance to re-read my post and admire my wordsmithing: "sufficiently within sufficiency" :shock:  :lol:


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## Dallaslawnnut (Feb 7, 2019)

MckinneyLawn said:


> I wanted to share my soil test to see what advice that y'all might have. I have really high pH which is caused by my calcareous clay. That clay also is why my calcium is through the roof. As far as the rest of the nutrients go I think I'm alright except for Magnesium, Iron in the back, and Potassium in the front. I did hit both yards last year with sulfur (can't remember how much). Thanks for your advice!


I'm in Allen. What soil test company did you use?


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## Suburban Jungle Life (Mar 1, 2018)

@Ridgerunner With an AA test, your rec for Mg is 140-250. Looking at the % sat, Mg is low. Would you recommend he add any?


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## Ridgerunner (May 16, 2017)

@Suburban Jungle Life 
"Measure twice. Cut once."
I try to be cautious. This is a single test. "One" does not make for a pattern and It takes at least two points to draw a line. So, what's the confidence level in the test results? We don't know how thoroughly sampling was performed https://thelawnforum.com/viewtopic.php?f=24&t=7441 (no offense @MckinneyLawn or anyone else) , nor, no matter how unlikely, that there were no errors in lab testing. I prefer to tread lightly and just take off the rough edges to start.

"Do no harm."
A benefit/harm analysis. Even with an initial/single test, if there are no obvious red flags, there are some nutrients, if found below sufficiency levels, that can/should be adjusted as the possible benefit that can result outweighs the potential harm. N, P,K and S fall into this category as they are the nutrients most used by volume by the turf, N, K and S tend to move relatively quickly out of the root zone, and detrimental levels for P, K and S are quite high. Consequently, there is high potential for turf improvement due to correction and low potential for harm due to a moderate over-application. Another area subject to initial adjustment that has a high potential for benefit is pH due to its impact on nutrient availability. I prefer to be much more reserved in making adjustments to Ca, Mg and the trace/micro nutrients. I prefer to collect more data before amending unless they are below MLSN or they test at 0 zilch. Even then, at least with micros, I suggest in the interim using a low content supplement (like foliar or fortified fertilizers) for direct plant feeding/availability rather than rolling up our sleeves and adjusting the soil levels. If we needed to raise pH, then we may as well adjust Mg and Ca as one or both are going to be added by necessity during liming.

McKinney's Mg

Sure, it'd be ideal to bring the Mg levels up to within sufficiency range, so why would I NOT suggest adjustment? I'm not a big fan of trying to meet Base Saturation ratios (other than a passing nod to Mg:K) as studies have shown no correlation of Ca:Mg and plant performance/health and it also becomes a game of whack a mole. It just never seems to work out right. McKinney's Mg levels are in the high 80's, not in the sufficiency range, however, AA testing of Mg and Ca tend to produce lower tested levels than M3 testing. PACE MLSN deficiency Mg levels (via M3 testing) are <50, i.e. below which turf starts to show adverse affects. With AA levels in the high 80s, I'm reasonably confident that the Mg levels are not deficient (below M3 50 ppm) and that it's unlikely that the turf will suffer any ill effect this year. There's time to gather more data and re-evaluate for adjustment next year. What's the possible harm? McKinney states that he has a clay soil and with CEC in the 20s with moderate OM, its very likely that the soil has a significant clay component. Mg will bind clay particles more tightly, increasing the potential for making a "tighter" soil. One that is very hard when dry impeding water penetration and rooting.

That's just my point of view. It' not some hard and fast iron clad rule. McKinney is welcome to adjust Mg if he wishes. He could use Epsom Salts or PoMag (or Sul-Po-Mag). PoMag can be hard to find and Epsom Salts (not being a prill) can be somewhat of a challenge to apply. It all depends on how much effort and care he wants to invest, but IMO, his Mg isn't at a critical level that would require adjustment at this time.


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## Ridgerunner (May 16, 2017)

@Dallaslawnnut The fine print at the bottom IDs the lab as Waypoint. I don't know which of the tests he requested from them. @g-man is pretty familiar with their tests and may be able to suggest the appropriate test you would want.


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## g-man (Jun 15, 2017)

This looks like the SW1, which Waypoint made for alkaline soils.

@MckinneyLawn Can you explain differences between front and back lawn? There are some differences in the results (eg. sodium).

One thing to add, since you have a pH above 7, you will benefit from foliar applied iron (FAS, FEature) to green up your bermuda.


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## Suburban Jungle Life (Mar 1, 2018)

Thanks @Ridgerunner for the sound advice and thorough explanation!


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## MckinneyLawn (Apr 20, 2018)

@Dallaslawnnut I used Waypoint Analytical and I requested their SW3 test which is what they recommend for alkaline soils.



Dallaslawnnut said:


> MckinneyLawn said:
> 
> 
> > I wanted to share my soil test to see what advice that y'all might have. I have really high pH which is caused by my calcareous clay. That clay also is why my calcium is through the roof. As far as the rest of the nutrients go I think I'm alright except for Magnesium, Iron in the back, and Potassium in the front. I did hit both yards last year with sulfur (can't remember how much). Thanks for your advice!
> ...


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## MckinneyLawn (Apr 20, 2018)

@g-man



g-man said:


> This looks like the SW1, which Waypoint made for alkaline soils.
> 
> @MckinneyLawn Can you explain differences between front and back lawn? There are some differences in the results (eg. sodium).
> 
> One thing to add, since you have a pH above 7, you will benefit from foliar applied iron (FAS, FEature) to green up your bermuda.


@g-man There are a few differences between the back and the front lawn. The back lawn has better drainage than the front lawn (I will be adding some downspout drains this year). Also I paid much more attention to the front than the back last year. I just started with this lawn care thing last year so I started out with the front yard and am adding the backyard this year.


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## MckinneyLawn (Apr 20, 2018)

@Ridgerunner Thanks for the more in-depth explanation. As for the sampling, for each yard, I took 10 randomized samples with a soil probe. I sampled to a 6 inch depth and I discarded the top OM layer. I mixed the 10 samples thoroughly and then picked through the sample to remove any roots or other plant tissue that was pushed lower into the sample by the probe. I also took some of the sample to do my own pH test just to see how I compared with a professional lab. I did a 1:1 soil to water test and got an 8 for the front yard and 7.8 for the back yard. I will probably do my own pH tests throughout the seasons to see if weather and/or I can affect it.

One thing that I did notice while taking the samples is that my top 4ish inches is the black "gumbo" clay and lower than that was the calcareous clay (+/- 2 inches). I may take some more samples and test the pH myself to see if it is better in the higher layers (knowing that my results are +/- .5 pH).

One other thing that I did was ask Waypoint to do a carbonate test on the same samples (should have results soon). I will then do a "fizz" test on some of the soil sample that I have left and compare that to the Waypoint result. This will allow me to roughly test the carbonate levels myself at different times and at different depths without spending more money on testing. That way I will be able to see the affects of any acid treatment that I use (citric acid, sulfuric acid, elemental sulfur, ammonium sulfate, etc.).

After doing some of my own research, I did start to have concerns about the agglomeration affect of magnesium in clay as the last thing I need is "stickier" clay.

For the lower P value I know that P does not really move in the soil at all so I was thinking that the only time that I would add any P is when I aerate the lawn and that way it at least gets to the 3 inch depth vs sitting in the top 1 inch.

I will be using feature this year for foliar feeding to try and work around the nutrient tie-up from the high pH.


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## Ridgerunner (May 16, 2017)

Sounds good. 
You may want to sample just the top 4" from here on out, unless you saw a fair share of roots in that 4-6" zone.
Once you get the results back from your lime/carbonate test, you should be able to estimate the amount of acidifying agent you will need to temporarily lower pH. I'm afraid you are going to be unhappy with the prospects.


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## MckinneyLawn (Apr 20, 2018)

Ridgerunner said:


> Sounds good.
> You may want to sample just the top 4" from here on out, unless you saw a fair share of roots in that 4-6" zone.
> Once you get the results back from your lime/carbonate test, you should be able to estimate the amount of acidifying agent you will need to temporarily lower pH. I'm afraid you are going to be unhappy with the prospects.


@Ridgerunner I know I'm probably going to be pretty disappointed. With that being said, the time that I had the greenest lawn was after spraying it with diluted sulfuric acid @Greendoc style. It may end up being a monthly thing I do this this year, the only hard part is that my neighbors like to ask a lot of questions and when I did it last year, I did it at 4 am to eliminate any questions as to my PPE :lol: :lol: !


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## Spammage (Apr 30, 2017)

Ridgerunner said:


> Once you get the results back from your lime/carbonate test, you should be able to estimate the amount of acidifying agent you will need to temporarily lower pH. I'm afraid you are going to be unhappy with the prospects.


@MckinneyLawn whatever you apply for bringing down pH at your house will likely have the same results at my house. Unfortunately, the limestone bed is going to win.


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## Ridgerunner (May 16, 2017)

Yes, @Greendoc would be the "go to" on that.


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## Greendoc (Mar 24, 2018)

I know what Bermuda growing on pH 7.5 soil looks like. Not pretty. Not very responsive to fertilizer applications. An application with better optics than Sulfuric acid would be 1 lb Citric Acid per 1000 sq ft. This is to be dissolved in water and sprayed. I do this especially for large areas because Sulfuric cannot be applied through my power sprayers. It will eat through brass and stainless steel. You also do not need to worry as much about PPE. Another suggestion I can make is to make all of your N applications as Ammonium Sulfate. Organics or slow release will not work as well. Iron and Manganese are elements important for green color in the grass. I make spray applications of those elements in chelated, soluble form if the pH is low. I know those element are showing up in the soil test, however that is because soil samples are subjected to an extraction procedure involving strong acids and chelating agents.


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## MckinneyLawn (Apr 20, 2018)

@Greendoc Thanks for the advice about the Citric Acid. Is the manganese in Feature enough? (Feature is 2.5% Mn as manganese citrate applied at 2 oz/1000 once per month)


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## Greendoc (Mar 24, 2018)

Yes. FEature is what I use. My typical lawn is on pH 7.5 soil with a lot of carbonates.


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## MckinneyLawn (Apr 20, 2018)

For an update on my soil test, I got the carbonate test back and it said <200 mg/kg for both front and back.


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## Ridgerunner (May 16, 2017)

Less than 200 mg/kg. That's less than 0.1%? For a pH 8 soil, I'm stumped. Have you done your own vinegar test yet?
http://edis.ifas.ufl.edu/hs1262


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## MckinneyLawn (Apr 20, 2018)

@ridgerunner I did the vinegar test today. I actually weighed my soil and weighed how much 10 drops of vinegar were so I could get a more accurate result. I gave up after it hit ~12.5 percent calcium carbonate. Out of curiosity after the solution had stopped fizzing, I did a ph test and it was at 5. I did the experiment again with more water (1:1 soil to water) and testing pH along the way. After reacting with calcium carbonate that makes up 0.07 percent of the soil, it had dropped to 6.1 pH. It was at a 7.8 pH before I started adding vinegar. It looks to me at first glance that although I do have a lot of calcium carbonate in my soil, a lot of it will not react even in an acidic environment.(something something about reaction equilibrium  )


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## Ridgerunner (May 16, 2017)

I'm not sure I understand the process that you employed, but I'll assume that your results are valid. If you have the time, contact Waypoint about their fizz test results and your 8 pH, it would be interesting to see what they say is the probable reason that they found such low amounts of carbonate.


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## MckinneyLawn (Apr 20, 2018)

@ridgerunner I called them last week and they said that they ran the wrong carbonate test and that they should have run a saturated paste test. They ran the new test and it came back and said that I have 0 meq/L on both the front and the back. If I get a chance I'll talk with them and ask them exactly what that means.


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## g-man (Jun 15, 2017)

It would be interesting to discuss with Dr. Oscar Ruiz. 0 carbonate? It just doesn't sound right.


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