# Help me understand results from two different sources



## nemesis256 (Mar 27, 2021)

I did an experiment this spring with my soil test. I collected it, mixed it, and split it to sent it to two sources to compare. First is from Maine, second is from New Hampshire.

For the most part they agree. The two that stick out are P and K. Not only do they disagree with low vs optimum, but also when I try to convert the units of measurement they're way off. My googling for formulas to convert with are obviously incorrect.

So what gives?


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## robjak (Mar 31, 2020)

Is there more to the top one? It does not list the test extraction method.


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## Virginiagal (Apr 24, 2017)

Maine is using the Morgan extractant, New Hampshire is using Mehlich 3. The extractants will extract different amounts of the nutrients. The Maine results for cations are in percentages, what percentage of base cations each nutrient makes up of the total. New Hampshire is giving you ppm, parts per million.
https://umaine.edu/soiltestinglab/home/faq/
https://umaine.edu/soiltestinglab/wp-content/uploads/sites/227/2016/07/handbook.pdf
I'm guessing Maine is saying the percentage of potassium is low because your calcium and magnesium percentages are high. New Hampshire is saying you have an acceptable of potassium and isn't comparing it to the other base cations.
More reading material, see chapter 5:
http://s3.amazonaws.com/udextension/lawngarden/files/2012/10/CHAP5.pdf

How did their fertilizer recommendations compare?


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## nemesis256 (Mar 27, 2021)

Thanks for the response. I guess I should have included more of the report than just the levels found. Here's more of both below.



Virginiagal said:


> I'm guessing Maine is saying the percentage of potassium is low because your calcium and magnesium percentages are high. New Hampshire is saying you have an acceptable of potassium and isn't comparing it to the other base cations.


You flipped the two states BTW, the one with the colored bars is Maine. I'll go through those PDFs to try to understand better.

The recommendations for fertilizer seem different. New Hampshire (second one) kind of reads like generic recommendations, while Maine seems more personalized.


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## Virginiagal (Apr 24, 2017)

Yes, I was misreading. I think I must have looked at phosphorus instead of potassium for New Hampshire. New Hampshire is saying you're low in potassium.

Both states don't want you using much nitrogen, do they? I wonder if it's because you're so far north and have a short growing season in the fall. Maine says you need 0.8 of phosphorus and 1.3 lb of potassium for the year yet the fertilizers and amounts it recommends don't supply that much. New Hampshire recommends 0.9 or 1.8 or 2.7 lb of nitrogen and of potassium, depending on level of maintenance, but no phosphorus (unless you are seeding).

How do you normally fertilize? Ryegrass takes more nitrogen than fine fescue and you have both.


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## nemesis256 (Mar 27, 2021)

Virginiagal said:


> How do you normally fertilize? Ryegrass takes more nitrogen than fine fescue and you have both.


My normal source is the generic Scotts (meaning none of their "season" fertilizers) which is a 32-0-4. I did an application a few weeks ago which was about 0.5-0.6 lbs of N/1000 sqft.

I also add other things based on soil tests. For example a soil test last season showed low K, so I applied sulfate of potash at 2 lbs / 1000 sqft, 3 times over last summer.

Now with this latest soil test, I got Ammonium Sulfate since the one from Maine shows low sulfur. That will be my source of N for the next two apps, which I'm planning on doing mid June then late August when the temps start cooling. I'll be aiming for 0.5 lbs / 1000 sqft for both of those apps.

My main question with these soil test results is which do I pay attention to. Maine makes it look like I should apply phosporus (which is odd, I hear soils in the North East are often high in P), then New Hampshire makes it look like I should apply potassium. Then if you flip P and K for each state, they're both optimum.


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## Virginiagal (Apr 24, 2017)

Both states are recommending potassium, so do some SOP. Probably not as much as you did last year. SOP has sulfur, as does ammonium sulfate. Two applications of SOP would be plenty. As for phosphorus, you could add a little bit, hedging between the two tests. Or skip it. Maine's recommendation of 10 lb of 20-4-8 split into two applications for the whole year (5 lb in the spring, 5 lb late summer) would give only 0.4 lb for the year, hardly worth mentioning. Mulch mowing your fall leaves will provide some phosphorus. Maybe you could count that as your phosphorus application.

So, you don't fertilize past late summer? Maine said late August, New Hampshire said pre Labor Day. That seems so strange to me, as fall around here, and most of the country with cool season grass, is the best time to fertilize, September and October being the time to pour on the nitrogen and take advantage of the best growing time of the year. But then again, your grass may not benefit as much from a lot of nitrogen (fine fescue anyway). And maybe winter begins very early for you. When do the leaves fall? When does it start snowing?


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## nemesis256 (Mar 27, 2021)

Virginiagal said:


> So, you don't fertilize past late summer? Maine said late August, New Hampshire said pre Labor Day. That seems so strange to me, as fall around here, and most of the country with cool season grass, is the best time to fertilize, September and October being the time to pour on the nitrogen and take advantage of the best growing time of the year. But then again, your grass may not benefit as much from a lot of nitrogen (fine fescue anyway). And maybe winter begins very early for you. When do the leaves fall? When does it start snowing?


I might do another application mid September. It is the best time to fertilize we just have to do it a little earlier. Leaves fall mid October, and soil temps are hitting 50 at that time as well. First snow isn't very reliable recently (damn climate change) but lets say late November early December.


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