“There is one other description in this Report for 1903 that is of special interest to me,” said Percy.  “This relates to a type of soil which the surveyors found in the low level areas of prairie land in McLean County, Illinois, and which they have called Miami black clay loam.  I think we have several acres of the same kind of soil on our own little farm.  I found the following statements on page 787: 

“’When the first settlers came to McLean County they found the areas occupied by the Miami black clay loam wet and swampy, and before these areas could be brought under cultivation it was necessary to remove the excess of moisture.  With the exception of a few large ditches for outlets, tile drains have taken the place of open ditches.  Drainage systems in some instances have cost as much as $25 an acre, but the very productive character of the soil, and the increase in the yields fully justify the expense.  There are few soils more productive than the Miami black clay loam.  Some areas have been cropped almost continuously in corn for nearly fifty years without much diminution in the yields.’”

“Now there you are again,” said the Chief.  “Drainage, that’s all it needed.  You see it’s a simple matter; and that’s what the Leonardtown loam needs in places.  Give it good drainage and good cultivation with a rotation of crops, and you’ll get results all right.”

“Has the Bureau of Soils tried these methods on any of this soil near Washington?” asked Percy.

“No use,” replied the Chief.  “We’ve got the scientific facts and besides, as I told you, some few farms are kept up in both Prince George and St. Mary counties and they are as good demonstrations as anyone could want.  Now I suggest that you meet some of our scientists.”

CHAPTER XXII

THE CHEMIST’S LABORATORY

The Chief showed Percy into the laboratories of the Bureau and introduced him to the soil physicist and the soil chemist.  Percy was greatly interested in the various lines of work in progress and gladly accepted an invitation to return after lunch and become better acquainted with the methods of investigation used.

In the afternoon the physicist showed him how the soil water could be removed from an ordinary moist soil by centrifugal force, and the chemist was growing wheat seedlings in small quantities of this water and in water extracts contained in bottles.  The seedlings were allowed to grow for twenty days and then other seedlings were started in the same solution and also in fresh solution, and it was very apparent that in some cases the wheat grew better in the fresh solutions.

The chemist explained that he also analyzed the soil solutions and water extracts from different soils and that there was no relation between the crop yields and the chemical composition of the soils.

“But it seems to me,” said Percy, “that your analysis refers to the plant food dissolved in the soil water only at the time when you extract it.  How long a time does it require to make the extraction?”