# Results in - M3 vs SW3 Testing



## RaleighBerm (Aug 19, 2021)

NC State did the M3. Waypoint did the SW3. I thought this might spark some discussion.

Last year, NC State also ran an M3. Major differences are:

Zn and Mn skyrocketed

P-I (Phos Index) doubled in front

CEC increased by ~4

Any advice for this year and forward? Straight N for awhile this year?

I'm trying to figure out:


Disparity in N recommendations from each vendor

Difference in P results (different testing methods? how to rationalize?) Should I skip P this year?

Surprised my clay % is not higher (texture analysis). But CEC is pretty low


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## Virginiagal (Apr 24, 2017)

Are you going to post the other soil tests you want to talk about? All I'm seeing is front and back lawns from Waypoint.


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## robjak (Mar 31, 2020)

VirginiaGirl, the NC tests are just above the waypoint test.


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## robjak (Mar 31, 2020)

Are both the NC and Waypoint test from the same sample of soil? Meaning you took a bunch of cores and mixed them together, then split it into 2 bags, one to NC and the other to Waypoint?

Also, i thought the SW3 was for High PH soils. Yours is not.


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## g-man (Jun 15, 2017)

This is trying to compare apples and oranges. Two different test methods, but they yield similar results. Almost the same pH in both method. The bottom test needs lime (40lb/ksqft).

You don't need more P. It is actually high and you should avoid products with P.

Your soil is sandy per the test results. Sandy soils tend to have lower CEC. Take this into account when you water your lawn (less likely to hold on to water).


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## RaleighBerm (Aug 19, 2021)

Hey all.

Yes @Virginiagal the two tests are (each) combined in 1 image to consolidate. Sorry, I should have clarified that!

Yes @robjak the samples were taken and split just as you described.


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## Virginiagal (Apr 24, 2017)

The nitrogen recommendations are not based on any test results. It's for the type of grass you're growing. Bermuda uses a lot of nitrogen compared to other grasses. Here are some guidelines from the warm season forum on fertilizing (and other things):
https://thelawnforum.com/viewtopic.php?t=1651

NC may have a lower target pH than Waypoint. I'd add lime to that one lawn that has a pH of 6.0.


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