Kenneth said:

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

Might you know why their testing does not include Nitrogen?

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.

http://www.css.msu.edu/SoilTesting/

(I hope it's safe to assume that the situation is the same in others states.)
--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)