was a rich soil, for the teacher in college had said that the more
common prairie land and most timber lands were much less durable and
needed thorough investigation at once, while the flat recently
drained heavy black land could wait a few years if necessary.

Percy first worked out the data for the Miami black clay loam. The
chemist had analyzed the soil separates for only four constituents,
and they showed the following amounts per acre of plowed soil to a
depth of six and two-thirds inches, averaging two million pounds in
weight:

2,970 pounds of phosphorus

38,500 pounds of potassium

18,440 pounds of magnesium

46,200 pounds of calcium

He then made the computations for the average of the Leonardtown
loam of St. Mary County, Maryland, with results as follows:

160 pounds of phosphorus

18,500 pounds of potassium

3,480 pounds of magnesium

1,000 pounds of calcium