Deconvoluting the Meaning of Our Soil Tests

It's one thing to get the soil tested, it's another thing to understand the results and what to do about it. We first got our soil tested in 2009, but recently, with all of the work going on to prepare our land for spring planting, we decided to get our soil tested again. We took a sample from our North field before the onset of derocking commenced and then took another sample after the top soil had been turned and the rocks removed from the top soil. We sent our soil samples to two different laboratories and were really perplexed at the different numbers that came back. In order to try to figure out what was going on, I turned to the Internet and found a really good presentation called Grapevine Nutrition presented by Mark Chien of the Penn State Cooperative Extension. The first number that is really important is the pH of the soil. This is because the availability of the macro- and micronutrients to the vines are very pH dependent as shown in this diagram:

In Mark Chien's presentation, he recommends that the pH for growing grapevines be between 5.5-7.0.
Our soil analysis also included values of the phosphorus, potassium, calcium, magnesium, boron, iron, manganese, copper, zinc, aluminum and organic matter content of our sample. Mark Chien recommends the following values:

We will use the above information as a guide to amending our soils this fall. (I know, it is getting late!) The other thing was that because we had analyses done by two different laboratories, the information for one came back as pounds per acre and the other one as parts per million (ppm). How does one do that conversion? I looked at the chapter on Nutrient Management in Wine Grape Production Guide for Eastern North America and found out how to do it on page 157. I'll try to summarize the information:
In metric units there are:

1,000,000 milligrams (mg) in 1 kilogram (kg)
1,000,000 micrograms (μg) in 1 gram (g)

Therefore, 1mg/kg = 1μg/g = 1ppm (1 part per million)
One acre-furrow slice in agriculture is defined as 2,000,000 pounds of soil, so, to get the conversion from metric to pounds/acre, or pounds/acre to metric do the following:

ppm x 2 = pounds/acre
pounds/acre ÷ 2 = ppm

Now, back to looking at our soil analysis results.