# A little confused with my soil test report.



## MexTex (Sep 24, 2020)

I just receive my soil test report (results below). According to the Bermuda seed that I am about to use, soil ph needs to be 6.0 - 6.5. My report is telling me that my ph is low, but my calcium is at a critical level and my magnesium is moderate. Wouldn't adding the recommended amount of Lime bring my calcium level way past the critical level? Or should I not worry about it? Any help would be much appreciated.

Also, can I add lime, fertilize with starter fertilizer and seed in the same day? Whats the best course of action?

What I have done so far: 
- Herbicide was sprayed about a month ago to kill off all weeds
- Yesterday soil was tilled and dragged smooth


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## Ridgerunner (May 16, 2017)

Can you confirm that this is a Texas A&M test (Mehlich 3 extraction)? How much of the 8 acres are you planning to maintain as a lawn? Is this soil similar to sugar sand (beach sand)?


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## MexTex (Sep 24, 2020)

Yes this is the Texas A&M soil test. It is the routine analysis R1. The total area to be seeded with Bermuda is 3/4 of an acre, around 30,000 sq feet. The dirt isn't like beach sand, it's is a little sandy when dry and worked over. When we dug out our pool, the dirt that was removed was used to level out this area.


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## Deadlawn (Sep 8, 2020)

I see a few issues with this soil test. You have a low pH of 5.4, however, your calcium is high and your magnesium is optimal. The only way to raise your pH is with lime, however lime will raise your calcium. Dolomitic lime will raise your calcium less than calcitic lime, but will then raise your magnesium above optimal. I can only guess their very low recommendation of 10 lbs per 1000 sq ft is trying to balance this double edged sword, but won't really raise your pH much.

I also see as problematic their recommendations for N-P-K app. Yes, you would benefit from all of these, but they give no indication of maximum amounts per app. There is no indication in the test on things like cation exchange capacity (CEC) or scoop density which are important indicators of how much lime/fertilizer a soil will need to achieve results.

Maybe @g-man has some ideas.


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## Ridgerunner (May 16, 2017)

> My report is telling me that my ph is low, but my calcium is at a critical level and my magnesium is moderate. Wouldn't adding the recommended amount of Lime bring my calcium level way past the critical level? Or should I not worry about it? Any help would be much appreciated.
> 
> Also, can I add lime, fertilize with starter fertilizer and seed in the same day? Whats the best course of action?


Neither Calcium nor Magnesium high levels are anything to be concerned about. They can influence soil texture/structure, but high levels will not adversely impact plant/turf health. (There is a caveat below.)

Nutrient wise, this is poor soil. Nutrient levels across the board are close to being or are below levels recommended to prevent poor turf performance (growth, disease, vigor, drought resistance etc.).
Compare to these minimum levels of MLSN (these are "bottom line" levels.):
pH: >5.5 to <8.5
P: 21 ppm
Ca: 331 ppm
Mg: 47 ppm
K: 37 ppm
S: 7

You should raise all of the above nutrients.
Ideally you would use Potassium Sulfate (0-0-50) and ammonium sulfate (21-0-0) for K and N as they will provide much needed sulfur and triple supper phosphate (0-46-0) for P.
They can be hard to source and shipping via on-line can be prohibitive, but make an effort to find them locally.
In the alternative (for this season) you can use a triple NPK (e.g. 10-10-10, 13-13-13, 19-19-19 etc.)for your needed N, P and K. Apply at the rate of 0.5 to 1 lb of N per thousand square feet.

I'd suggest you use a dolomitic lime to raise pH and Mg levels. 10lbs per thousand seems low (depends on their target pH), but use their recommend 10lb/M rate this year.

About applying everything at once, I'd advise against that. Lime can cause N to gas off resulting in a loss of 10-30% of N, that's not a big deal, but it's not very cost effective. However (here's that caveat), the flush of Ca and Mg released by the lime can/will interact with the P, locking P up and making it unavailable to the turf. As seedlings and young turf needs readily available P for rooting, this can have an adverse effect on new turf. I'd advise holding off on the lime until this Fall. 
Good luck


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## g-man (Jun 15, 2017)

Deadlawn said:


> I see a few issues with this soil test. You have a low pH of 5.4, however, your calcium is high and your magnesium is optimal. The only way to raise your pH is with lime, however lime will raise your calcium. Dolomitic lime will raise your calcium less than calcitic lime, but will then raise your magnesium above optimal. I can only guess their very low recommendation of 10 lbs per 1000 sq ft is trying to balance this double edged sword, but won't really raise your pH much.
> 
> I also see as problematic their recommendations for N-P-K app. Yes, you would benefit from all of these, but they give no indication of maximum amounts per app. There is no indication in the test on things like cation exchange capacity (CEC) or scoop density which are important indicators of how much lime/fertilizer a soil will need to achieve results.
> 
> Maybe @g-man has some ideas.


Follow what ridgerunner said. I'm not sure what you are talking about in regards to calcium and magnesium and double edge sword. They calculated the lime to get to 6.2pH (good for bermuda), just follow their calculation.


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## Deadlawn (Sep 8, 2020)

g-man said:


> Follow what ridgerunner said. I'm not sure what you are talking about in regards to calcium and magnesium and double edge sword. They calculated the lime to get to 6.2pH (good for bermuda), just follow their calculation.


Point taken @g-man. My biggest issue was that the soil lab recommended 2.7 lbs per 1000 sq ft of P and 2.3 lbs per 1000 sq ft of K, but didn't mention anything about maximum amounts per app or how far out time wise they should be spaced. I'm pretty sure you shouldn't apply all that at once. Bag rates are usually a small fraction of this. In the end, read the bag label carefully.

My other issue was the lack of info in the test on CEC, exchange acidity, etc. which all would figure into how much product to apply.

@MexTex's soil has about the same pH as my native soil did. My lab calculated 2 - 50 lb per 1000 sq ft apps of lime to get from 5.5 to 6.5 and that is in sandy soil with a low CEC of around 4.5.

Please help me understand.


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## g-man (Jun 15, 2017)

TAMU either sends extra info on applications in other papers or points you to their website. Most labs will only include the yearly or total nutrients needed to get to their ideal. Some labs dont tell you anything (eg. Logan).

The CEC can be calculated adding the cations. It is pretty low in this report, hence why ridgerunner asked about it being sand. It is near Houston, so sand is common.

They calculated the amount of lime to apply to this soil based on this soil values. Your soil is different and your lab calculated different needs for it.


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