The Story of the Soil Part 19

CHAPTER XXIII

MATHEMATICS APPLIED TO AGRICULTURE

PERCY left the Bureau of Soils with a feeling of deep appreciation for the uniform courtesy and kindness that had been accorded him, but with a firm conviction that the laboratory scientists were too far removed from the actual conditions existing in the cultivated field. He sought the quiet of his room at the hotel in order to study the bulletins he had received.

Even with his college training he found it difficult to form clear mental conceptions of the results of investigations reported in the bulletins. Sometimes the data were reported in percentages and sometimes in parts per million. No reports gave the amounts of the element phosphorus; but PO4 was given in some places and P2O5 in others. In Bulletin No. 22, the pota.s.sium and calcium were reported as the elements and the nitrogen in terms of NO3, while potash (K20), quicklime (CaO), and magnesia (MgO) were reported in Bulletin 54.

By a somewhat complicated mathematical process, he finally succeeded in making computations from the percentages of the various compounds reported in the soil separates and from the percentages of these different separates contained in the soils themselves and from the known weights of normal soils, until he reduced the data to amounts per acre of plowed soil.

He was especially pleased to find that the essential data were at hand not only for both the Leonardtown loam and the Porter's black loam, but also for the Norfolk loam, which he had learned from one of the soil maps was the princ.i.p.al type of soil southwest of Blairville on Mr. Thornton's farm; and, furthermore, the Miami black clay loam of Illinois was included. Percy knew the black clay loam 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 a.n.a.lyzed the soil separates for only four const.i.tuents, 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 pota.s.sium

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 pota.s.sium

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 pota.s.sium 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 pota.s.sium

12,360 pounds of magnesium

23,700 pounds of calcium

He viewed these figures a moment with evident satisfaction.

"Plenty of everything in this wonderful 'pippin land,'" he thought.

"Big yields reported for everything suited to that alt.i.tude. 'Can be worked year after year without apparent impairment of its fertility,' so the Report stated. I should think it might, especially since clover is one of the crops grown. Both phosphorus and pota.s.sium are way above our best black land. Magnesium two-thirds and calcium one-half of our flat land, but still greater than our common prairie, according to the average they gave us at college. And no doubt there is plenty of magnesian limestone in these mountains which could be had if ever needed. The soil surveyor certainly did not say too much in praise of the Porters black loam, considering that its physical composition is also all right."

He worked out the Norfolk loam to see what he would get if he accepted Miss Russell's dare. The following are the figures:

610 pounds of phosphorus

13,200 pounds of pota.s.sium

1,200 pounds of magnesium

3,430 pounds of calcium

"Rather low in everything," said Percy, "compared with any soil I know that has a good reputation. More uniformly poor but not so extremely poor as the Leonardtown loam."

He wished that the nitrogen had been determined by the chemist, even though he knew the organic matter and the nitrogen must be very low in the poor soils, but nowhere was any such record to be found in the bulletin. He found the statement, however, that all data were reported on the basis of ignited soil.

"That will reduce some of these amounts about one-tenth," he said to himself. "In our physics work in college, good soils generally lost about ten per cent. in weight by ignition, even after all hygroscopic moisture had been expelled; but these very poor soils haven't much to lose, I guess. They surely contain no carbonates and very little organic matter, although they may contain some combined water."

CHAPTER XXIV

THE NATION'S CAPITOL

PERCY spent three days in Was.h.i.+ngton.

"If I lived here long," he wrote his mother, "I think I should become as optimistic as the Secretary of Agriculture, even though the total produce of the original thirteen states should supply a still smaller fraction of the necessities of life required by their population. The Congressional Library is by far the finest structure I have ever seen. I cannot help feeling proud that I am an American when I walk through its halls and look upon the portraits of the great men who helped to make our country truly great.

"As I shook hands with the President of the United States at one of his public receptions held in the 'East Room' of the White House, I wondered if there was another country on the earth where the humblest subject could thus come face to face with the head of a mighty nation. In the Treasury Building I was permitted to join a small party of some distinction and shared with each of them the privilege of holding in my hands for a moment eight million dollars in government bonds.

"I have visited many of the great buildings, the Capitol, of course, and Was.h.i.+ngton's monument, which rises to a height of 555 feet above the surrounding land, or practically 600 feet above low-water level in the Potomac. There are many smaller monuments erected in honor of American heroes in various squares, circles, and parks throughout the City.

"The zoological garden took a full half-day, and I could have spent a much longer time there. They told me of a frightful occurrence that happened only last week. In a pool of water a very large alligator is kept confined by a low stout iron fence. A negro woman was leaning over the fence holding her baby in her arms and looking at the monster who seemed to be asleep; when, without a moment's warning, he thrust himself half out of the water and snapped the baby from her arms, swallowing it at one gulp as he settled back into the water. I fear the report is true enough, for they have made the fence higher in a very temporary manner, and I heard it mentioned by a dozen or more.

"I leave Was.h.i.+ngton by boat at five o'clock this afternoon, and I expect to land at Leonardtown, St. Mary county, Maryland, about six o'clock in the morning, when the boat will be ready to leave that port. It is a freight boat and stops for hours at large towns.

"I am planning for a trip into New England next week. I did not realize how easy it is to go there until I looked up the train service. In less than twelve hours' time, one can make the trip from the Virginia line, through the District of Columbia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut, Rhode Island, and into Ma.s.sachusetts,--ten different states, including the District. The trip from Galena to Cairo can hardly be made in so short a time, not even on the limited Illinois Central trains."

An hour before leaving the Was.h.i.+ngton hotel Percy chanced to meet a Congressman whom he had seen on several occasions at the University and who had spoken at the alumni banquet at the time of Percy's graduation.