Article by V. A. Tiedjens
Soil samples from many sections of the United States and Canada show a paucity of
available calcium even though the pH reading seems satisfactory. Studies made on these
soils show that the pH test, accurate for most purposes, does not indicate the available
calcium in the presence of other fertilizer ions. A high pH does not necessarily indicate
adequate calcium in the soil.
THE OHIO JOURNAL OF SCIENCE 65(4): 227, July, 1965