"STONE SOUP"
THE next forenoon Percy and Mr. West spent some time making some
further tests with hydrochloric acid and litmus paper in different
places on the farm; but the result only confirmed the previous
examinations.
"I never before saw any such light as now appears," said Mr. West.
"It seems to me that for the first time in the history of Westover,
covering about two centuries, a real plan can be intelligently made
based upon definite information looking toward the positive
improvement of the soil. While you have been away, I have been
looking up the lime matter. I find that a lime is being advertised,
and sold in small amounts, that is called hydrated lime, and it is
especially prepared as an agricultural lime. It is recommended by
some dealers as being fully equal to the ordinary commercial
fertilizer which sells at about $25 a ton, while this hydrated
agricultural lime can be bought for $8 a ton, and I think for a
little less in larger amounts. You mentioned also that you had seen
some one who had used hydrated lime, but it didn't seem to make much
of a clover crop. Of course, I understand from what you said that
his soil contained only one hundred and sixty pounds of phosphorus,
and I take it that lime alone could not markedly improve his soil;
but still I would like to know why, if he has one hundred and sixty
pounds of phosphorus in his plowed soil, he could not produce a few
good crops of clover. HOW much phosphorus does it require for a ton
of clover?"
"One ton of clover contains only five pounds of phosphorus," Percy
replied, "and of course the roots must also require some phosphorus,
although after the crop is produced and removed, the phosphorus
contained in the roots remains for the benefit of subsequent crops.
Thus we might suppose the land which contains one hundred and sixty
pounds of phosphorus ought to furnish the phosphorus needed for a
three ton crop of clover every year for ten years; but in actual
practice no such results are secured. The invoice of the plant food
in the soil is a matter of very great importance, for it reveals the
mathematical possibilities, but another matter of almost equal
importance is the problem of liberating plant food from this supply
sufficient for the crops to be produced year by year.
"Decaying or active organic matter is one of the great factors in
the liberation of plant food, and undoubtedly the extension or
distribution of the root system of the growing plant is another very
potent factor. If the root surfaces come in contact with one per
cent. of the total surface of the soil particles in the plowed soil,
then we might conceive of a relationship whereby one per cent. of
the phosphorus in that soil would be dissolved or liberated from the
insoluble minerals and thus become available as food for the growing
crop. We know that the rate of liberation varies greatly, with
different soils and seasons, and crops also differ in their power to
assist themselves in the extraction of mineral plant food from the
soil. The presence of limestone encourages the development of
certain soil organisms which tend to hasten some decomposition
process. But, all things considered, it may be said, speaking very
generally, that the equivalent of about one per cent. of the total
phosphorus contained in the plowed soil does become available for
the crops under average conditions. On this basis one hundred and
sixty pounds of phosphorus would furnish about one and one-half
pounds for the crops during one season. But in such a soil the
phosphorus still remaining may be the most difficultly soluble, and
the supply of decaying organic matter may be extremely low, so that
possibly less than one pound per acre would become available, and
this would meet the needs of less than four hundred pounds per acre
of clover hay. Furthermore, the supply grows less and less with
every crop removed.
"With your ordinary soil, carrying twelve hundred and seventy pounds
of phosphorus, perhaps you may be able by a liberal use of decaying
organic matter to liberate ten or fifteen pounds of phosphorus, or
sufficient for a crop of forty to sixty bushels of corn; and, with a
subsoil richer in phosphorus than the surface, and with more or less
of the partially depleted surface removed by erosion year by year,
the supply of phosphorus is thus permanently provided for unless the
bed rock is brought too near the surface. It is doubtful if the
direct addition of phosphorus to your sloping lands will ever be
necessary or profitable. Certainly such addition is not advisable
until you have brought the land to as high a state of fertility as
is practicable by means of limestone, legumes, and manure."
"That seems clearly to be the case with most of the land now under
cultivation on this farm," said Mr. West "Can you tell me anything
about this hydrated lime?
"I can tell you it is correctly named," Percy replied. "_Hydrated_
means _watered,_ and an investment in hydrated lime is properly
classed with other watered investments. If you prefer to use
hydrated lime I would suggest that you buy fresh burned lump lime
and do the hydrating yourself, which only requires that you add
eighteen pounds of water to each fifty-six pounds of quick lime; in
other words, that you slack the lime by adding water in the proper
proportion. Both quick lime and hydrated lime are known as caustic
lime. Webster says that the word _caustic_ means 'capable of
destroying the texture of anything or eating away its substance by
chemical action.'
"This definition is correct for caustic lime, as you can easily
determine by keeping your hand in a bucket of slacked lime a few
minutes. Caustic lime eats away the organic matter of the soil. In
an experiment conducted by the Pennsylvania Experiment Station,
during a period of sixteen years, eight tons of hydrated lime
destroyed organic matter equivalent to thirty-seven tons of farm
manure, as compared with the use of equivalent applications of
ground limestone; and, as an average of the sixteen years, every ton
of caustic lime applied liberated seven dollars' worth of organic
nitrogen, as compared with ground limestone. That this much
liberated nitrogen was essentially wasted and lost is evidenced by
the fact that larger crops were produced where ground limestone was
used than where burned lime was applied.
"The limestone must be quarried whether used for grinding or for
burning, and the grinding can be done for twenty-five cents a ton
where a large equipment with powerful machinery is used and where
cheap fuel is provided, as near the coal mining districts. It need
not be very finely ground. If ground to pass a sieve with twelve
meshes to the linear inch, it is very satisfactory, provided that
all of the fine dust produced in the grinding is included in the
product. You see the soil acids are slightly soluble and they attack
the limestone particles and are thus themselves destroyed or
neutralized. If, however, you ever wish to use raw rock phosphate,
insist upon its being sufficiently fine-ground that at least ninety
per cent. of it will pass through a sieve with ten thousand meshes
to the square inch, this being no finer than is required for the
basic slag phosphate, of which several million tons are now being
used each year in the European countries. Like the raw rock
phosphate, the slag gives the best results only when used in
connection with plenty of decaying organic matter."
"That reminds me," said Mr. West, "of what one of the fertilizer
agents said about raw phosphate. He said the use of raw phosphate
with farm manure reminded him of 'stone soup,' which was made by
putting a clean round stone in the kettle with some water. Pepper
and salt were added, then some potatoes and other vegetables, a
piece of butter and a few scraps of meat. 'Stone soup,' thus made,
was a very satisfactory soup. He said that in practically all of the
tests of raw phosphate conducted by the various State Experiment
Stations, manure has been used as a means of supplying organic
matter to liberate the phosphorus from the raw rock, but in such
large quantity as to be entirely impracticable for the average
farmer to use on his own fields; and his opinion was that the entire
benefit was due to the manure. He had a little booklet entitled
'Available or Unavailable Plant Food--Which?' published by the
National Fertilizer Association, and said I could get a copy by
addressing the Secretary at Nashville, Tennessee."
"Fortunately," said Percy, "this is not a question of opinion but
one of fact; and it has been discovered that the fertilizer agents
who are long on opinions and short on facts prefer to sell four tons
of complete fertilizer for $80, or even two tons of acid phosphate
for $30, rather than to sell one ton of raw phosphate, containing
the same amount of phosphorus, for $7.50. In the manufacture of
acidulated fertilizers, one ton of raw phosphate, containing about
two hundred and fifty pounds of the element phosphorus, is mixed
with one ton of sulfuric acid to make two tons of acid phosphate;
and, as a rule, these two tons of acid phosphate are mixed with two
tons of filler to make four tons of complete fertilizer. A favorite
filler is dried peat, which is taken from some of the peat bogs, as
at Manito, Illinois, and shipped in train loads to the fertilizer
factories. The peat is not considered worth hauling onto the land in
Illinois, even where the farmers can get it for nothing; but it
contains some organic nitrogen, and, by the addition of a little
potassium salt, the agent is enabled to call the product a
'complete' fertilizer.
"Experiments with the use of raw rock phosphate have been conducted
by the State Agricultural Experiment Stations over periods of twelve
years in Maryland, eleven years in Rhode Island, twenty-one years
(in two series) in Massachusetts, fourteen years (in two series) in
Maine, twelve years in Pennsylvania, thirteen years in Ohio, four
years in Indiana, and from four to six years on a dozen different
experiment fields in different parts of Illinois.
"I have here some quotations taken from the directors of several of
these experiment stations which fairly represent the opinions which
they have expressed concerning their own investigations. Thus the
Maryland director says:
"'The results obtained with the insoluble phosphates has cost
usually less than one-half as much as that with the soluble
phosphates. Insoluble South Carolina phosphate rock produced a
higher total average yield than dissolved South Carolina rock.'
"The Rhode Island director comments as follows:
"' With the pea, oat, summer squash, crimson clover, Japanese
millet, golden millet, white podded Adzuka bean, soy bean, and
potato, raw phosphate gave very good results; but with the flat
turnip, table beet, and cabbage it was relatively very inefficient.'
"The following statement is from the Massachusetts director:
"'It is possible to produce profitable crops of most kinds by
liberal use of natural phosphates, and in a long series of years
there might be a considerable money saving in depending at least in
part upon these rather than upon the higher priced dissolved
phosphates.'
"The director of the Maine State Experiment Station gives us the
following:
"'For the first year the largest increase of crop was produced by
soluble phosphate. For the second and third years without further
addition of fertilizers, better results were obtained from the plots
where stable manure and insoluble phosphates had been used.'
"The stable manure and insoluble phosphates here referred to were
not applied together, but on separate plots. In deed, the raw
phosphate was not used in connection with manure either in Maryland,
Rhode Island, Massachusetts, Maine, Pennsylvania, or Indiana; and in
the extensive experiments in progress in Illinois the raw phosphate
has been used, as a rule, not with farm manure, but with green
manures; and wherever manure has been used in connection with the
raw phosphate, as in Ohio, the comparison is made with the same
amounts of manure applied without phosphate.
"The Pennsylvania Report for 1895, page 210, contains the following
statement:
"'The yearly average for the twelve years gives us a gain per acre
of $2.83 from insoluble ground bone, $2.45 from insoluble South
Caroline rock, $1.61 from reverted phosphate, and 48 cents from
soluble phosphate, thus giving us considerably better results from
the two forms of insoluble phosphate than from the reverted or
soluble forms.'
"The Indiana director reports as follows:
"'It will be seen that during the first and second years the rock
phosphate produced little effect, while the acid phosphate very
materially increased the yields. During the third and fourth
seasons, however, the rock produced very striking results, even
forging ahead of the acid. This and very similar investigations in
progress lead us to believe that rock phosphate is a cheap and
effective source of phosphorus where immediate returns are not
required.
"In the Ohio experiments eight tons of manure per acre were applied
once every three years in a three-year rotation of corn, wheat, and
clover, three different fields being used, so that every crop might
be grown every year. The average yields for the thirteen years where
manure alone was used were:
53.1 bushels of corn
20.6 bushels of wheat
1.63 tons of hay
"The average yields on the unfertilized land were:
32.2 bushels of corn
11.4 bushels of wheat
1.16 tons of hay
"If the corn is worth 35 cents a bushel, the wheat 70 cents, and the
hay $6 a ton, in addition to the expense of harvesting and
marketing, then the total value of the manure spread on the land is
$2.07 a ton.
"Where $1.20 worth of raw phosphate (320 pounds) were added in
connection with the manure the average yields were as follows:
61.4 bushels of corn
26.3 bushels of wheat
2.23 tons of hay
"And where $2.40 worth of acid phosphate (320 pounds) were used with
the same amount and kind of manure the following average yields were
secured:
60.4 bushels of corn
26.5 bushels of wheat
2.16 tons of hay
"These are the actual yield, and by any method of computation yet
proposed, each dollar invested in raw phosphate has paid back much
more than has a dollar invested in acid phosphate."
"And was the use of the raw phosphate really profitable?" asked Mr.
West.
"Well, you might figure that out for yourself," Percy replied,
"preferably using the average prices for your own locality for corn,
wheat and clover. As I figure it at prices below the ten-year
average for Illinois, the raw phosphate paid about eight hundred per
cent. net on the investment."
"Eight hundred per cent! You must mean eight per cent. net.
"No, Sir, I mean eight hundred per cent. net, but you had better
take the data and make your own computations. But does it not seem
strange that, with such positive knowledge as this available, many
of the Illinois landowners who have managed to sell off enough of
their original stock of fertility in grain or stock at good prices
to enable them to more than pay for their lands, should continue to
invest their surplus in more land with hope that it will pay them
eight per cent. interest, when they could secure many times that
much interest from investing in the permanent improvement of the
land they already own?"
"Perhaps it is not so strange," replied Mr. West. "I fear that some
of their ancestors did the same thing in Virginia and other Eastern
States until the land became poor, and then of course they were
'land poor.' But, say, that 'stone soup' wouldn't be so bad for
those Ohio landowners, would it? I should think they would avail
themselves of the positive information from their experiment
station. Speaking of soup, I wonder if it isn't time for lunch! But
tell me; are the Illinois farmers doing anything with raw
phosphate?"
"Yes, they are doing something, but by no means as much as they
ought. About two months ago a group of the leading farmers from our
section of the State went up to Urbana to look over the experiment
fields, some of which have been carried on since 1870. The land is
the typical corn belt prairie, and consequently the results should
be of very wide application. Well, as a result of that day's
inspection of the actual field results, an even twelve carloads of
raw phosphate were ordered by those farmers upon their return home;
and I learned of another community where ten carloads were ordered
at once after a similar visit. As an average of the last three years
the yield of corn on those old fields has been 23 bushels per acre
where corn has been grown every year without fertilizing, 58 bushels
where a three-year rotation of corn, oats and clover is followed,
and in the same rotation where organic matter, limestone, and
phosphorus have been applied the average yield has been 87 bushels
in grain farming and 92 bushels in live-stock farming.
"I attended the State Farmers' Institute last February, and there I
met many men who have had several years' experience with the raw
rock. Usually they put on one ton per acre as an initial application
and plow it under with a good growth of clover; and, afterward,
about one thousand pounds per acre every four years will be ample to
gradually increase the absolute total supply of phosphorus in the
soil, even though large crops are removed.
"A good many of our thinking farmers are now using one or two cars
of raw phosphate every year, and they are figuring hard to keep up
the organic matter and nitrogen. The most encouraging thing is the
very marked benefit of the phosphate to the clover crop, and of
course more clover means more corn in grain farming, and more corn
and clover means more manure in live-stock farming.
"On the Illinois fields advantage is taken of these relations in the
developing of systems of permanent agriculture. You see, if the
phosphate produces more clover, then more clover can be plowed under
on that land; or, if the crops are fed, then more manure can be
returned to the phosphated land than to the land not treated with
phosphate and not producing so large crops. Really the phosphate is
not given full credit for what it has accomplished in the Ohio
experiments; because, while the land receiving phosphated manure has
produced about one-fourth larger crops than the land receiving the
untreated manure, the actual amounts of manure applied have been the
same, whereas one-fourth more manure can be produced from the
phosphated land and if this increased supply of manure were returned
to the land it would increase the supply of nitrogen and thus make
still larger crop yields possible."
"That is surely the way it would work out in practical farming,"
said Mr. West. "I think I did not tell that $4.80 a ton is the
lowest quotation I have been able to get as yet for ground limestone
delivered at Blue Mound Station."
"That would make its use prohibitive," said Percy. "You ought to get
it for just one-fourth of that, or for $1.20 a ton. In Illinois we
can get it delivered a hundred miles from the quarry for $1.20 a
ton. It costs no more for a thirty-ton car of ground limestone than
the farmer receives for a cow; and the cost of a car of fine-ground
natural phosphate is about equal to the price of one horse."
"Of course, our limestone supplies are essentially inexhaustible,"
said Mr. West, "but is that also true of our natural phosphate
deposits?"
"It is not true of the high-grade phosphate," replied Percy; "for,
according to the information furnished by the United States
Geological Survey, it is evident that the known supplies of our
high-grade phosphate will be practically exhausted in fifty years if
our exportation continues to increase at the prevailing rate. After
that is gone we may then draw upon our low-grade phosphate deposits,
which though probably not inexhaustible are known to be exceedingly
extensive."