160 pounds of phosphorus
18,500 pounds of potassium
3,480 pounds of magnesium
1,000 pounds of calcium
Percy stared at these figures when he brought them together for comparison. He then checked up his computations to be sure they were right.
"Almost twenty times as much phosphorus!" he said to himself. "Is it possible? And more than forty times as much calcium! Let me see! It takes one hundred and seventeen pounds of calcium for four tons of clover hay. The total amount in the plowed soil of the Leonardtown loam would not be sufficient for eight such crops; and six crops of corn such as we raised one year on our sixteen acres would take more phosphorus from the land than is now left in the plowed soil of this Leonardtown loam. The magnesium is not quite so bad—about one-fifth as much as in our black soil, and the potassium is almost one-half as much as we have."
Percy next turned to the Porters black loam, which he had noticed was to be found not many miles from Montplain. He thought he might induce Mr. West to drive with him to the upper mountain slope in order that they might see that land. His computations for the Porters black loam gave the following results:
4,630 pounds of phosphorus
48,300 pounds of potassium
12,360 pounds of magnesium