Accurate soil testing...?

[Kenneth]

Howdy,

Is there a reasonable way to get accurate soil testing done?

Here's why I ask:

First, my local cooperative extension does testing, but, to my amazement, none of there available tests (and they have many) includes an assessment of nitrogen.

Next, I own a soil test kit, but discovered that it showed nitrogen depletion even when testing a highly concentrated solution of nitrogen fertilizer in water. When I found that, I called the manufacturer and was told that it may have expired. I asked where in the detailed instructions there was information about expiration, but of course, there was no such.

In any case, what's the solution? I would welcome any specific suggestions.

Sincere thanks,

[Pat Kiewicz]

MSU Soil and Plant Nutrient Lab. does offer nitrogen testing *during the growing season* (it was mentioned in the June 1 CAT Bulletin) and there's not just one single test.

their FAQ: Why doesn't the regular MSU soil test include nitrogen analysis?

*Soil nitrate levels are the best indicator of nitrogen availability. Because these levels fluctuate widely depending on rainfall and soil temperature, the best time to take soil nitrate samples in while the cropis growing. within two weeks of supplemental nitrogen applications. *A soil sample taken months ahead of this time will not provide an accurate measure of the nitrogen available to the plants.

/end quote

I would think that such service would be available in other states as well, but only seasonally (for the same reason) and likely home gardeners are not ever encouraged to get some of the tests available to the professionals.

Was the packaging marked with an expiration date?

Many items come with a 'best before xx-xx-xx' on the packaging without mention of that fact in the package inserts.

[Kenneth]

Hello again,

Nope... That was the problem. The representative explained to me that after a few months, the reagents were of little use. I asked if there were a date (coded or otherwise) on the package, and she said "No, we don't do that." Nice.

All the best,

[FDR]

Could you please tell us the maker or brand of test kit this is so we can avoid buying them?

[Kenneth]

Hello again,

Certainly...

"luster Leaf Products" Woodstock IL.

Nicely packaged, easy to use, good instructions, meaningless measurements.

All the best,

[FDR]

Thank you.

[Steve]

I'm sure you are right about the meaningless measurements. Maybe the other tests (other than nitrogen) are of some use, but then again, who knows? I understand that testing for nitrogen in a meaningful way is not easy. I'm sure they felt they had to include it anyway so it would appear to be a complete test kit. They have to sell them and make money after all.

Steve

[Repeating Rifle]

in article [e-mail], Kenneth at [e-mail] wrote on 6/5/05 3:48 AM:

What was the fertilizer? The nitrogen may not be in available form. I do not think ammonium sulfate is immediately available without some microbial activity.

Bill

[Kenneth]

Hi Bill,

It was urea...

All the best,

[Dominic-Luc Webb]

Perhaps a convenient way to get some measure of soil quality is to use some indicator plants. I know of a couple plants that grow well above pH 7 and promptly die in acidic soil, etc... Others so dramatic responses to depletion of specific nutrients. Most plant physiology books have a nutrient deficiency key from which you can trace down specific problems. These are usually based on common garden plants such as the tomato.

Dominic

[Thomas H. O'Reilly]

Send it to a local company that specializes. Here in Illinois, I've used

You can check out their web site, and see sample reports, etc. Their S10 report is for home gardeners, they have other reports for farmers and orchardists. It's not very expensive, and is comprehensive. They will also make amendment recommendations based on your desired plants.

[Kenneth]

Hello again,

I have made note of your suggestion, but have a question:

Might you know why their testing does not include Nitrogen?

All the best,

[Pat Kiewicz]

Here's what the Soil and Plant Nutrient Lab at Michigan State University has to say in their FAQ: /begin quote

Why doesn't the regular MSU soil test include nitrogen analysis?

*Soil nitrate levels are the best indicator of nitrogen availability. Because these levels fluctuate widely depending on rainfall and soil temperature, the best time to take soil nitrate samples in while the cropis growing. within two weeks of supplemental nitrogen applications.

*A soil sample taken months ahead of this time will not provide an accurate measure of the nitrogen available to the plants.

/end quote

Nitrogen tests are available during the growing season. Note that there are separate tests for different forms of nitrogen. Available tests:

PSNT - Pre-sidedress Nitrate -N PSNT + NH4 - with Ammonium - N NO 3 - N - Nitrate - Nitrogen NO 3 + NH4 - with Ammonium - N TKN - Total Nitrogen

Some of these are available with a standard analysis and some are priced as standalone tests.

hope it's safe to assume that the situation is the same in others states.)