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Cyril G. Hopkins.

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ever was any good is all right yet if you'll grow clover, and you
can start that with a little manure if you need it. I have done it
in Iowa, and I know what I am talking about.

"Now my Bureau of Soils can give you just the information you want.
We are making a soil survey of the United States, and we have soil
maps of several counties right here in Maryland. You can take that
map and pick out any kind of land you want, - upland or bottom
land, - sandy soil, clay soil, loam, silt loam, or anything you
want."


CHAPTER XXI

IN THE OFFICE OF THE CHIEF


"SHOW this gentleman to the Bureau of Soils," said the Secretary to
the boy who came as he pushed a button.

"All the world loves an optimist," said Percy to himself as he
followed the boy to another office where he met the Chief of the
Bureau of Soils, who kindly furnished him with copies of the soil
maps of several counties, including two in Maryland, Prince George,
which adjoins the District of Columbia, and St. Mary county, which
almost adjoins Prince George on the South.

These maps were accompanied by extensive reports describing in some
detail the agricultural history of the counties and the general
observations that had been made by the soil surveyors.

"I desire to learn as much as I can regarding the most common upland
soils," Percy explained. "Not the rough or broken land, but the
level or undulating lands which are best suited for cultivation. I
am sure these maps and reports will be a very great help to me."

"I think you will find just what you are looking for," said the
Chief. "You can spread the maps out on the table there and let me
know if I can be of any assistance. You see the legend on the margin
gives you the name of every soil type, and the soils are fully
described in the reports. One of the most common uplands soils in
southern Prince George county is the Leonardtown loam, and this type
is also the most extensive soil type in St. Mary county.

"The same type is found in Virginia to some extent. While the soil
has been run down by improper methods of culture, it has a very good
mechanical composition and is really an excellent soil; but it needs
crop rotation and more thorough cultivation to bring it back into a
high state of fertility. The farmers are slow to take up advanced
methods here in the East. We have told them what they ought to do,
but they keep right on in the same old rut."

For two hours Percy buried himself with the maps and reports.
Finally the Chief came from his inner office, and finding Percy
still there asked if he had found such information as he desired.

"I find much of interest and value, but I do not find any complete
invoice of the plant food contained in these different kinds of
soil."

"You mean an ultimate chemical analysis of the soil?" asked the
Chief.

"Yes, a chemical analysis to ascertain the absolute amount of plant
food in the soil. I think of it as an invoice; but I see that you do
not report any such analyses."

"No, we do not," answered the Chief. "We have been investigating the
mechanical composition of soils, the chemistry of the soil solution,
and the adaptation of crop to soil. We find that farmers are not
growing the crops they should grow; namely, the crops to which their
soils are best adapted. For example, they try to grow corn on land
that is not adapted to corn."

"It seems to me," said Percy, "that our farmers are always trying to
find a crop that is adapted to their soil. Down in 'Egypt,' which
covers about one-third of Illinois, the farmers once raised so much
corn that the people from the swampy prairie went down there to buy
corn, and hence the name 'Egypt' became applied to Southern
Illinois. But there came a time when the soil refused to grow such
crops of corn; the farmers then found that wheat was adapted to the
soil. Later the wheat yields decreased until the crop became
unprofitable; and the farmers sought for another crop adapted to a
still more depleted soil. Timothy was selected, and for many years
it proved a profitable crop; but of late years timothy likewise has
decreased in yield until there must be another change; and now whole
sections of 'Egypt' are growing red top as the only profitable crop.
After red top, then what? I don't know, but it looks as though it
would be sprouts and scrub brush, and final land abandonment, a
repetition of the history of these old lands of Virginia and
Maryland."

"Well, can't they grow corn after red top?" asked the Chief.

"Many of them try it many times," replied Percy, "and the yield is
about twenty bushels per acre, whereas the virgin soil easily
produced sixty to eighty bushels."

"And they can't grow wheat as they once did?"

"No, wheat after timothy or red top now yields from five to twelve
bushels per acre, while they once grew twenty to thirty bushels of
wheat per acre year after year.

"If they rotate their crops, they would probably yield as well as
ever," said the Chief.

"No, that, too, has been tried," replied Percy. "The Illinois
Experiment Station has practiced a four-year rotation of corn,
cowpeas, wheat, and clover on an experiment field on the common
prairie soil down in 'Egypt,' and the average yield of wheat has
been only twelve bushels per acre during the last four years, but
when legume crops were plowed under and limestone and phosphorus
applied, the average yield during the same four years was
twenty-seven bushels per acre."

"Probably the increase was all produced by the green manure,"
suggested the Chief. "Organic matter has a great influence on the
control of the moisture supply."

"That was tested," said Percy. "The green manure alone increased the
average yield to only fourteen bushels while the green manure and
limestone together raised the average wheat yield to nineteen
bushels, the further increase to twenty-seven bushels having been
produced by the addition of phosphorus."

"Well, Sir," said the Chief, "we have made both extensive intensive
investigations concerning the chemistry of the soil solution by very
delicate and sensitive methods of analysis we have developed, and we
have also conducted culture experiments for twenty-day periods with
wheat seedlings in the water extract of soils from all parts of the
United States, and the results we have obtained have changed the
thought of the world as to the cause of the infertility of soils."

"But you have not made analyses for total plant food in the soils or
conducted actual field experiments with crops grown to maturity?"
asked Percy.

"No, we have not done that," answered the Chief. "Those are old
methods of investigation which have been tried for many years and
yet no chemist can tell in advance what will be the effect of a
given fertilizer upon a given crop on a given soil."

"That is true," said Percy, "but neither can any merchant tell in
advance just what effect will be produced on the next day's business
by the addition of a given number of a given kind of shoes to a
given stock on his shelves. There are many factors involved in both
cases."

"Yes, you are right in that," said the Chief, "we are just beginning
to understand the chemistry of the soil, and we hope soon to have
very complete proof of the advanced ideas we already have concerning
the causes of the fertility and infertility of soils."

"Referring to the specific case of the Leonardtown loam of
Maryland," said Percy, "I find the following statement on page 33 of
the Report of the Field Operations of the Bureau of Soils for 1900.
After describing the Norfolk loam of St. Mary County, the writer
says:

"'The Leonardtown loam is a very much heavier type of soil. It
covers about forty-one per cent. of St. Mary County. The soil is a
yellow silty soil, resembling loess in texture, underlaid by a clay
subsoil with layers or pockets of sand. This soil has been
cultivated for upward of two hundred years, but it is now little
valued and is covered with oak and pine over much of its area. It is
worth from $1 to $3 per acre. The cultivated areas produce small
crops of corn, wheat, and an inferior grade of tobacco.'"

"The generally low estimation in which this land is held is probably
wholly unjustified," replied the Chief. "There are two or three
farms in the area which, under a high state of cultivation with
intelligent methods, will produce from twenty to thirty bushels of
wheat per acre and corresponding crops of corn. Those farmers are a
credit to the country. They furnish the towns with good milk and
butter and vegetables, and they also help to keep the towns clean
and sanitary by hauling out the animal excrements, and other waste
and garbage that tend to pollute the air and water of the village."

"I can see how that might maintain the fertility of those farms,"
said Percy. "It seems that the general condition of this kind of
land is about the same in Prince George County. On page 45 of the
1901 Report of the Field Operations of the Bureau of Soils, I have
noted the following statement:

"'The Leonardtown loam, covering 45,770 acres of the area, is the
nearest approach among the Maryland Coastal Plain Soils to the heavy
clays of the limestone regions of Western Maryland and Pennsylvania.
The surface is generally level and the drainage fair. The soil is
not adapted to tobacco, and has consequently been allowed to grow up
to scrub forest, so that large portions of it are at present
uncleared. Such unimproved lands can be bought for $1.50 to $5.00 an
acre, even within a few miles of the District line. The soil has
been badly neglected, and when cultivated the methods have not been
such as to promote fertility. When properly handled, as it is in a
few places, good yields of wheat, corn and grass are obtained.'"

"That's right," said the Chief, "exactly right. Upon the whole it is
one of the most promising soils of the locality, although it is not
considered so by the resident farmers."

"You mean that it should be handled the same as is done by the
successful farmers of St. Mary County?" inquired Percy.

"Yes, it needs thorough cultivation and the rotation of crops; and
the physical condition of the soil needs to be improved by the
addition of lime and manure, or green crops turned under."

"I have been looking over some of the other Reports of Field
Operations," said Percy." I became interested in the description of
a Virginia soil called Porters black loam. I find the following
statements on page 210 of the Report for 1902:

"'The Porters black loam occurs in all the soil survey sheets,
extending along the top of the main portion of the Blue Ridge
Mountains in one continuous area. This type consists of the broad
rolling tops and the upper slopes of the main range of the Blue
Ridge Mountains. Locally the Porters black loam is called "black
land" and "pippin" land, the latter term being applied because, of
all the soils of the area, it is pre-eminently adapted to the
Newtown and Albermarle Pippin. This black land has long been
recognized as the most fertile of the mountain soils. It can be
worked year after year without apparent impairment of its fertility.
Wheat winter kills, the loose soils heaving badly under influence of
frost. The areas lie at too high elevations for corn. Oats do well,
making large yields. Irish potatoes, even under ordinary culture,
will yield from two hundred to three hundred bushels per acre. It
seeds in blue grass naturally, which affords excellent pasturage.
Clover and other grasses will also grow luxuriantly upon it. The
areas occupied by this soil are mostly cleared.'"

"Yes, Sir," said the Chief, "the Potters black loam is a fine
soil - loose and porous as stated in the Report. You see it has a
good physical condition."

"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?"

"As a rule we shake the soil with water for three minutes and then
it takes twenty minutes to separate the water from the soil. This
gives us the plant food in solution and with the addition of more
water the nitrates, phosphoric acid, and potash in the soil
immediately dissolve sufficiently give us a nutrient solution of the
same concentration as we had before. Thus there is always sufficient
plant food in the soil so long as there is any of the original
stock."

"That is surely quick work," said Percy, "but I wonder if the corn
plant might not get somewhat different results from the soil
analysis which it makes."

"How do you mean?"

"Did you ever plant a field of corn and then cultivate it and watch
it grow with increasing rapidity, until along about the Fourth of
July every leaf seemed to nod its appreciation and thanks as you
stirred the soil; and to show its gratitude, too, by growing about
five inches every twenty-four hours when the nights were warm?"

"No," replied the Chemist, "I have never had any experience of that
sort. I am devoting my life to the more scientific investigations
relating to the fundamental laws which underlie these soil fertility
problems."

"Well, I was only thinking," Percy continued, "that you analyze a
fraction of a pound of soil in a few minutes, while the corn plant
analyzes about a ton of soil by a sort of continuous process, which
covers twenty-four hours every day for about one hundred and twenty
days, and it takes into account every change in temperature and
moisture, the aeration with any variation produced by cultivation,
and also the changes brought about by the nitrifying bacteria and
all other agencies that promote the decomposition of the soil and
the liberation of plant food, including the action upon the
insoluble phosphates and other minerals of the carbonic acid exhaled
by the roots of the corn plants, the nitric acid produced by the
process of nitrification, and the various acids resulting from the
decay of organic matter contained in the soil."

"I am very familiar with the literature of the whole subject of soil
fertility," replied the Chemist, "and our theories are being
accepted everywhere. I have just returned from a lecture tour
extending from Florida to Michigan, and our ideas and methods are
being very generally adopted, not only in this country but also in
Europe."

"The Chief of the Bureau very kindly permitted me to look over the
maps and reports relating to the soils of Maryland and Virginia,"
said Percy, "but in this literature I found no data as to the amount
of plant food contained in the various soil types that have been
found in the surveys. May I ask if the Bureau has made any analyses
to ascertain the total amounts of the different essential plant food
elements contained in these different soils?"

"No," the Chemist replied, "a chemical analysis gives practically no
information concerning the fertility of the soil. We have made no
ultimate analyses of soils, although we have used the same methods
of analysis in a study of the partial composition of the soil
separates, or particles of different grades, such as the sand, the
silt, and the clay."

"And have you also determined the percentages of sand, silt, and
clay in the soils themselves?"

"Oh, yes, the physical composition of the soil is a matter of very
great importance, and this is always determined and reported for
every soil. Did you not see that in the Reports you examined this
morning?"

"I think I did notice it," Percy replied, "but it is so easy for the
farmer himself to tell a sandy soil from a clay soil that I did not
appreciate the value of those physical analyses.

"In any case, I shall be very glad to know what results were
obtained from the chemical analysis of the soil separates to which
you referred."

"Those results are all reported in Bulletin No. 54 of the Bureau of
Soils," said the Chemist, "and I have extra copies right here and
will be glad to present you with one. And let me give you our
Bulletin 22 also. This will enable you to get a clear idea of the
principles we are developing which are solving the soil fertility
problems that have completely baffled the scientists heretofore."


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 potassium 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 principal 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 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

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

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 altitude. '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 potassium 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 potassium

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


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Online LibraryCyril G. HopkinsThe Story of the Soil; from the Basis of Absolute Science and Real Life, → online text (page 10 of 23)