Soil pH and "the diagram"

You've almost certainly seen some version of the soil pH and relative nutrient availability diagram. The first of these was a beautiful, colored chart, in a March 1935 Virginia Agricultural Extension Bulletin article written by Nicholas Albert Pettinger. The article is available for download from Virginia Tech.

Download Pettinger's article: A useful chart for teaching the relation of soil reaction to the availability of plant nutrients to crops

Wouldn't it be great to have a copy of one of those…