Ken-n-Nancy Soil Test - Spring 2020

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ken-n-nancy
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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by ken-n-nancy » September 12th, 2020, 9:46 am

I'm still planning on collecting an autumn soil sample this year from the front lawn area along the road, to see what sodium, potassium, and magnesium levels are like in September, rather than right after the ground thaws out in the spring, to help determine if I should be making springtime gypsum applications in the area near the road.

Also putting a note here to remind myself, when posting the fall soil test results, to ask about Andy's thoughts as to if the use of humates (specifically The Andersons Humic DG) might be helpful for our soil conditions, as described in Addition of Humates to Soil Plans.

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ken-n-nancy
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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by ken-n-nancy » September 28th, 2020, 2:17 pm

Today, I mailed off to Logan Labs a recently-collected soil sample from the front lawn area in order to specifically check to see what has happened with sodium levels over the summer in the area below the roadside (pictured way above earlier in the thread).

Also curious to see how the other cations have fared over the summer, particularly
  • calcium (having made no lime applications this year and also very little Bay State Fertilizer) and
  • potassium (for which we made applications of sulfate of potash 3 times, each time at 2#SOP/ksqft, for 1#K/ksqft on 5-21-2020, 6-26-2020, and 8-17-2020).
I haven't performed a fall soil test previously, so I'm curious to see what the results look like.

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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by MorpheusPA » September 28th, 2020, 5:54 pm

"Call him Ken. Some hours ago—never mind how long precisely—having little or no cations in his soil, and nothing particular to interest him in the gardens, he thought he would sample about a little and see the chemical parts of his world."

I might have something there.

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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by ken-n-nancy » September 28th, 2020, 6:02 pm

MorpheusPA wrote:
September 28th, 2020, 5:54 pm
"Call him Ken. Some hours ago—never mind how long precisely—having little or no cations in his soil, and nothing particular to interest him in the gardens, he thought he would sample about a little and see the chemical parts of his world."

I might have something there.
Definitely worth a chuckle. It's nice that not everybody in the world has quite the same sense of humor. Keeps life interesting. ;)

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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by MorpheusPA » September 28th, 2020, 7:02 pm

ken-n-nancy wrote:
September 28th, 2020, 6:02 pm
It's nice that not everybody in the world has quite the same sense of humor. Keeps life interesting. ;)
Translation: Dude, you are warped. But this time it was mildly amusing instead of slightly scary.

I tend to keep it under control online and I'm ten times worse in person. I married somebody as bad as I am, and most of my friends are in the same range. Imagine, if you will, six to ten of us together, all with a Mars black sense of humor.

It usually starts with, "I love children, but couldn't eat one all by myself..." and goes right downhill from there.


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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by edslawn » September 28th, 2020, 7:02 pm

.....😄

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ken-n-nancy
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Updated soil test results now in!

Post by ken-n-nancy » October 5th, 2020, 6:12 pm

Today I received the results of the soil test for the sample I collected on 9/24/2020. As mentioned earlier in the thread, I collected this new sample along the road in the front lawn to see if the "autumn" conditions varied in any significant way from the spring sample, particularly in regard to sodium and the other cations.

Well, I'm not entirely sure what to make of the results. I've always known that there would be some variation from test to test, given that we're sampling things that aren't uniform across the entire lawn, so I would think there would be a fair bit of variation, just in the fact that the collected soil is from slightly different locations each time. For this particular sample, I followed my standard approach of 30 cores, keeping the portion of soil between 3" and 4" depth, and mixing all the cores together for sending to Logan Labs. However, I took all of these cores in the section of my lawn within about 25' of the road, spanning the length of our roadside, with about 15 of the cores about 8' from the road and the other 15 cores about 15' from the road. All cores were collected from sections of soil below the grade of the road. There's a photo further above in this thread showing the general area.

In any case, it's hard to know whether any of the changes are just normal variation from test to test, or if the changes are due to focusing the samples along the roadside, or if the changes are due to actual different conditions in the soil. Of course, the actual changes in the test are a combination of all those factors, and probably others, too.

I may as well just stop talking about the test and just show you the numbers. Of course, the real question is whether or not to do anything differently?

Oh, and a few more details on what soil-related applications have been made this area this year:
  • 2020-05-21: Bay State Fertilizer (4-3-0) at 0.64#N/ksqft with
  • 2020-05-21: Sulfate of Potash (0-0-50) at 2#SOP/ksqft
  • 2020-06-17: Collected soil sample that was tested by Logan Labs on 6/25/2020
  • 2020-06-26: Bay State Fertilizer (4-3-0) at 0.64#N/ksqft
  • 2020-06-26: Sulfate of Potash (0-0-50) at 2#SOP/ksqft
  • 2020-06-26: Borax at 3T/ksqft
  • 2020-06-26: Manganese Sulfate Monohydrate at 3T/ksqft
  • 2020-08-17: Bay State Fertilizer (4-3-0) at 0.62#N/ksqft
  • 2020-08-17: Sulfate of Potash (0-0-50) at 2#SOP/ksqft
  • 2020-08-17: Borax at 3T/ksqft
  • 2020-08-17: Manganese Sulfate Monohydrate at 3T/ksqft
  • 2020-09-24: Collected soil sample that was tested by Logan Labs on 10/5/2020
Image

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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by andy10917 » October 5th, 2020, 10:15 pm

I'm a little surprised by the numbers, but probably not as much about the items that changed as why some DIDN'T CHANGE MORE.

Sodium near the road is no surprise in New England in the Spring. Sodium salt is cheap and used heavily for deicing roads. Now they've moved away from pure (Sodium) salts somewhat as (sodium) salts don't work well below 20F. There has been a move toward Magnesium Chloride and Calcium Choride mixes (with Sodium) salts, But Sodium salts are pretty easily washed out of the soil, and I was expecting a bigger drop in the Base Saturation in Sodium than you got. Why is it hanging around? The dry year? There was still plenty of rain if you compare it to many other places. And why the Magnesium drop? Magnesium Chloride washing out is the "logical" guess, but it's a guess all the same - I don't know what they use for deicing in your area. But the drop in Magnesium and Sodium is clearly the reason for the drop in pH. My question remains: why didn't Sodium drop under 3% ???

So, Calcium rose. If you didn't use Gypsum this year, the only thing I can think of is Calcium Chloride in the mix for deicing. Yet another guess.

I know you were looking for answers, not more (new!) questions. But this is why we recommend that samples be taken from all over the yard and mixed together when doing soil remediation work - the farther apart and varied that things are when you sample, the more likely things will "average out" when you send the soil to Logan. The more homogeneous the samples, the more likely that the samples will be more extreme.

I was actually expecting a bigger drop in pH, on a bigger move toward the mean for NH.

So, do you want to have me look over the test for anything else that I see, or was this an experiment in "where the hell did the Sodium come from?"

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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by ken-n-nancy » October 5th, 2020, 11:53 pm

andy10917 wrote:
October 5th, 2020, 10:15 pm
I'm a little surprised by the numbers, but probably not as much about the items that changed as why some DIDN'T CHANGE MORE.

...

I know you were looking for answers, not more (new!) questions. But this is why we recommend that samples be taken from all over the yard and mixed together when doing soil remediation work - the farther apart and varied that things are when you sample, the more likely things will "average out" when you send the soil to Logan. The more homogeneous the samples, the more likely that the samples will be more extreme.
Thanks, Andy, for taking a look. I guess I'm viewing this mostly as a bit of an experiment to see if the sodium number dropped over the summer. I see that it did, but not as much as I had hoped. Also, as you mention, some of the other changes are hard to explain.

One thing I do want to mention is that I go to significant effort every time I collect a sample to collect a varied sample which is representative of the entire area. As I mentioned in my earlier post, this particular sample wasn't just 2 cups of soil from 1 shovelful of dirt. Rather, I combined 30 separate soil cores, each taken only from the 3-inch to 4-inch soil depth, from 30 different locations in the lawn. A rough depiction of where the soil cores came from is shown in the picture below. I actually kept 30 cores, even though there are fewer circles than that in the picture. (I got tired of drawing circles for the illustration; there's only 24 circles in the image, but I actually collected 30 samples along two long imaginary lines like the ones shown.) My spring sample probably would have included about 16-20 cores from the depicted area, with the other 10-14 cores having been taken from the part of the front lawn in the far left area of the photo where the main "front lawn" is located (kind of "around the corner" at the end of the area of trees).

Image

A big unknown in this for me is how much normal variance is expected from one soil test to the next? I am sure there will be variance, but I don't know how much is reasonable to expect, even under "perfect conditions." I don't know how much soil is actually used by a lab for a "soil test." Clearly, the entire contents of the ziploc bag I used (which probably contained about 2 cups of soil) weren't tested, as I often hear of samples being "retested" by Logan Labs. But I wonder how much soil actually gets put into solution for the test? 1/32 of a cup? 1/8 of a cup? 1/2 of a cup? The answer matters because soil is far from homogenous -- I mean, it's not like a bowl of chocolate pudding which is pretty much uniform. Rather, soil is composed of thousands of tiny particles, each of which is itself quite distinct from the others. Minerals as we see them in rocks in the environment are sometimes uniform, sometimes very heterogenous, sometimes layered. Soil is a composite of thousands of "tiny rocks" and "tiny rock fragments" that are each quite different from one another, as well as the organic matter and bits of who-knows-what. As to whether or not the soil sample is really a representative cross section of what is in the entire sampled area, I would expect there to be a lot of variation, just due to whether or not the random locations I picked happened to miss any pockets that contain more of one mineral than another. I just don't know how much to expect.

Even under ideal conditions, there will be variation from test to test taken from a single mixed bag of soil, but again, I don't know how much is typical.

Then, since this test wasn't the same bag of soil as the spring test, there will be variation between that bag and this one, even if the 30 cores for each bag were collected on the same day, from immediately adjacent holes. In this case, there is even more variation, as the 30 cores I pulled this time weren't from adjacent holes. Indeed, this recent sample probably only represented about 60% of the area I consider to be "the front lawn." Maybe I should have collected this sample to better match the area covered by the samples I collected in the spring, given that most of the roughly 40% of the "front lawn" not tested this time would have never received any road salt, being too far from the road, but I tested this area to focus on the area that may be affected by road runoff.

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ken-n-nancy
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Re: Ken-n-Nancy Soil Test - Spring 2020

Post by ken-n-nancy » October 6th, 2020, 12:37 am

In any case, moving on to the analysis of the actual numbers, it does at least seem that the 6/25/2020 and 10/5/2020 samples were taken from the same lawn. Most items are pretty similar. I speculate that if a soil remediation plan were suggested for each of these lawns, that the recommended course of action would be about the same for both.

Actually, that's a good question... What would be the recommended soil remediation plan for the most recent sample?

Seems to me the recommendations would be pretty much the same for both samples, with the possible exception that the October test would suggest that epsom salt is necessary to be applied every 60 days along with sulfate of potash, while the June test would be marginal for the application of epsom salt.

But, other than that, no phosphorus, no lime based on either test. Boron indicated from both tests. Spring test indicates manganese, while the autumn test doesn't.

Regarding how much salt should have been expected to leach out of the soil, I found one article online talking about the subject which indicated that 6 inches of "good quality water" would give a 50% soluble salt reduction, 1 foot of water an 80% reduction, and 2 feet of water a 90% reduction. If the sodium in our soil were primarily from winter road salt, then it would be largely soluble, so one would expect to see leaching due to rainfall at a similar rate.

Our sample from June 17 measured a 5.24% sodium saturation level. Our Sept 24 test measured a 3.50% sodium saturation level. That's a 33.2% reduction. According to the weather station at our nearest airport in Manchester, NH (about 7 miles away), they received a total of 5.13" of rain between June 17 and Sept 24th (0.15" in the remainder of June, 3.02" in July, 1.22" in August, and 0.74" in the preceding portion of September). (Yes, it's been dry in NH, we normally average about 3.5" each month during those months.) A reduction of 33.2% from 5.13" of rain is in the same ballpark as 6" giving a 50% reduction, so that seems believable.

However, as to how the calcium went up, I don't have a great explanation. We haven't applied any lime this year. Sampling variation could be a cause. There is a little calcium (~2.0%) in Bay State Fertilizer, and we have applied it three times at a rate of about 16#/ksqft each time, but I don't think that would have made its way down to the 3-4 inch depth yet. I wonder if it's possible that calcium we applied the prior fall (9#/ksqft of calcitic lime on 9/19/2019) could have still been making its way down to the 3-4 inch depth?

Magnesium seemed to be the biggest mover. Sampling variation? Leaching out of the soil?

Sodium we already talked about. Changes in micronutrients don't seem particularly surprising. Manganese was the biggest mover; I did apply that twice this year.

In any case, I'm not sure that I have learned a whole lot from this test. We still need to keep applying potassium. Seems like epsom salt should also still be on our list of supplemental nutrients, and boron should still be in our plan. I haven't ever observed salt damage to the grass growing near the road in the spring, so maybe high sodium levels in our spring soil tests is just what we should expect?

I'm also wondering if we should bother with a spring soil test, or if we should just base our spring plan off this test, especially since we have a half-dozen years of history which basically all have a stabilized plan in the most recent few years?

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