What Went Wrong With My Soil Analysis?

[Scott O'Bar]

I realize this is a longshot to post this here, but perhaps someone could forward this to an agronomist or soil scientist colleague of theirs to get an answer to this.

I sent the same soil samples to different labs. One lab conducted a more traditional soil test, which included available P using a Modified Olsen Extract. NaHCO3 =0.5M, pH 8.5 Esp. Vis

The other lab tested for total elements using ICP OES.

The lab that tested for total P using ICP OES, showed less than 0.5mg P per kilogram of soil (less than the test threshold) in all samples sent (I sent six other samples to them from different areas of our land - none of the samples showed an above threshold amount).

The lab that tested available phosphorus showed 9.49ppm in the topsoil sample and 1.82ppm in the subsoil sample.

What's wrong with this picture?

Certainly one could assume the opposite might be the case when there's a value of 9.49ppm for Total P, and a subthreshold value for available P.