# Another Request for Help on Soil Test



## Hoosier (Jun 12, 2018)

Got my soil test back from Waypoint today. Reading through Ridgerunner's guide on it, I have some follow-up questions, and would appreciate any input on this. To preface, I put down 9#/K Milorganite at the beginning of April, a 15-0-15 liquid app mid-May per a Soil Savvy test recommendation, and no other P or K since. I've done monthly treatments of RGS (Humic) at 3oz/K since April 1st, and one GreeneEffect (7-0-0, 3% Sulfur, 6% Iron) app mid-June at the recommended rate. For the test, I took about 10 cores using a sampling tool, and sent in about 2 inch long pieces of each core, starting about 2 inches below the top (mixed them all up before sending).

Here's the result:


In that post, ranges for M3 are:
"Ranges (ppm)

P: 26-54
Ca: 500-750
Mg: 70-140
K: 75-176
Na: unreported/N.A.
S: 15-40
Fe: 50-100
Cu: 0.4-2.5
Zn: 1-2
Mn: 4-8, 8-16 for pH >7
B: unreported/N.A. (update: per PACE and R. Carrow: 0.4/0.5- 1.5)"

Looking at my test, a few values stick out. Calcium says 4024ppm, but isn't showing off the charts in the report, despite recommended max being 750ppm. Iron is showing 190, but according to Waypoint, that's close to optimal. Similar with Manganese - test showed 207ppm, but recommended max is 8 (or 16).

So, questions:
-Should I be concerned about the high (and low Sodium) values, or just let them go down over time?
-Looking forward, I plan to overseed in the fall... do these results indicate that, for the rest of the season, I should only apply N, and make sure to not apply any P or K until after testing again in the Spring, or should some kind of "starter" always be added to new seed?
-Lastly, the Ph is a bit high - recommended is between 6 and 7, closer to 7. Should I do anything to attempt to lower that?


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## Ridgerunner (May 16, 2017)

> Looking at my test, a few values stick out. Calcium says 4024ppm, but isn't showing off the charts in the report, despite recommended max being 750ppm. Iron is showing 190, but according to Waypoint, that's close to optimal. Similar with Manganese - test showed 207ppm, but recommended max is 8 (or 16).


The values from the thread are SLAN ranges. Soil nutrient levels that fall within those ranges are predicted to be in sufficient quantity for good plant growth. It's really all about nutrient deficiencies. Levels that fall below or above those ranges are not necessarily detrimental. Levels below range are more likely to create plant health issues in any CEC soil than levels that fall above range and the greater the shortage, the more likely a detrimental deficiency. In other words, avoiding low levels is more important as a determinant of plant performance. My understanding is that those SLAN ranges are based on "medium" soils (loams) with a CEC range of probably 10 to 20 (I've not been able to verify). (CEC is a soils ability to hold nutrients electromagnetically to soil particles with enough attraction to diminish the nutrient from leaching out, but not so strongly as to prevent them from being pulled off and become available to the plant.) Generally, sands have low CEC and nutrient holding capacity and deficient amounts (below SLAN range) of nutrients is likely. Higher CEC (>20) soils have large holding capacity and some clays will have nutrient levels well above SLAN range so the nutrients are abundant. Still abundance is not necessarily an issue. The question then becomes are they too abundant. The guideline employed to determine is a nutrient is too abundant is it's relationship to other nutrient, a ratio. If a nutrient is excessive (outside recommended ratio with another nutrient) it can interfere with the plants ability to use that other nutrient, creating a nutrient deficiency. Fortunately, the non-detrimental ratios between nutrients are so broad, they seldom are a problem or concern.
Enough of my blather.


> -Should I be concerned about the high (and low Sodium) values, or just let them go down over time?


No. Your CEC is 23.5, you would expect your soil to hold large amounts of nutrients (however take note of caveat above about micros). In addition your Ca levels (and possibly Mg) are somewhat inflated due to the acidity of M3 dissolving limestone and releasing Ca that is not otherwise available in your soil. The inflated Ca levels make Ca to other nutrient ratio determination somewhat unreliable. Even so, other than the Ca:K ratiio (and I wouldn't be concerned with that as you should feed your established turf with regular doses of K), all of your other nutrient ratios are fine. 
Although Sodium is suspected to be used in very small amounts by the plant in osmosis, it's not considered a nutrient and does not start to be an issue until it exceeds 5-15% of base saturation. Low is not a problem, it's desired.


> -Looking forward, I plan to overseed in the fall... do these results indicate that, for the rest of the season, I should only apply N, and make sure to not apply any P or K until after testing again in the Spring, or should some kind of "starter" always be added to new seed?


You should avoid P, you have plenty probably for the foreseeable future.
I suggest you employ a regular maintenance fertilizer program from this point forward of N and K. You might use a version of the "condensed/simple" method at the beginning of my thread. I also think you'll get good advice in the coll season forum on a fertilizer program and fertilizer sources and products.


> -Lastly, the Ph is a bit high - recommended is between 6 and 7, closer to 7. Should I do anything to attempt to lower that?


pH into the high 7s is no detriment to a great lawn (see @g-man's lawn pictures) . Attempting to lower pH is too often an exercise in futility, and not recommended.

*Edit*: I didn't state a "caveat above" concerning micros.  Caveat is that deficiency and excess levels for micro-nutrients hold true for any CEC soil, although levels outside (above or below) range aren't absolutes, whereas for high CEC soils you would expect higher levels of the Cations like Ca, Mg, and K and without detrimental affect as long as there are no severe imbalances.


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## Ridgerunner (May 16, 2017)

@NashDad 
The Ca and Mg range values is confusing, plain and simple.
I've decided to eliminate the suggestion that there is a top end to the range for those nutrients. Those sufficient/desired nutrient values now are indicated as just being greater than "> ###" a low end value (with apologies to R. Carrow).
I hadn't realized before how troublesome that could be to people employing the range guides.
Whether you intended to or not, thanks for bringing that to my attention. :thumbup: 
Hope that hasn't discouraged you from DIY.


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## g-man (Jun 15, 2017)

I have two things to add. Ammonium Sulfate will be a better source of a nitrogen for the high pH.

I don't love the Mn values higher than iron. The only good thing is that your pH is high so it should not too be available.

For green color, FAS is a good option for you.


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## Hoosier (Jun 12, 2018)

Thanks a bunch @Ridgerunner for the through explanation. I really appreciate the help. Was a little concerned when I got the results at some of the really high values, and not quite sure how they got to that level, but that's beside the point I guess. Glad I could inadvertently contribute some food for thought!

@g-man noted, and thanks for the tip. Haven't yet decided what my N schedule will be for the fall, but I'll give the FAS a shot. I normally prefer liquid apps, so this will fit right in to the plan


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