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LEVI STOCKBRIDGE

and the

Stockbridge Principle
of Plant Feeding

With
Compliments of the AuTHOR.

Extract from Tribute
By WILLIAM H: BOWKER
Read at the
Memorial Exercises at Amherst

1904

Printed
BOSTON 1911

on

LEVI STOCKBRIDGE

Professor of Agriculture in the Massachusetts Agricultural College from 1871
to 1882, and President of the College from 1880 to 1882.

1820—1904

BIOGRAPHICAL NOTE

LEV! STOCKBRIDGE

BIOGRAPHICAL NoTE: Levi Stockbridge, a man of the
type of Abraham Lincoln, was a farmer’s son and
for many years a practical farmer in Hadley, Mass.
Except for such schooling as he received at the
district school, and a few lectures in chemistry
which he attended at Amherst College, he was
self-taught. He possessed an alert mind, a reten-
tive memory, and a marked talent for clear,
forceful expression. Becoming distinguished as
a leader and public speaker, he was sent for sev-
eral terms to both branches of the Massachusetts
Legislature. He was Massachusetts’ first cattle
commissioner, and in the course of his twenty-
seven years’ continuous service in that office he
came to know nearly every farmer in the state,
who looked up to and respected him. One of his
greatest achievements was the quick and effective
manner in which he stamped out a threatened
epidemic of pleuro-pneumonia.

He. was instrumental in securing for the state
the Agricultural College located at Amherst,
Mass., in spite of ridicule and strong opposition.
He was its first farm superintendent; later, pro-
fessor of agriculture, and for two years its presi-
dent. During his connection with the college, at
considerable personal inconvenience, he frequently
endorsed the notes of the college to the local
banks, thus tiding it over financial stress. He

BIOGRAPHICAL NOTE

‘

was also ‘‘ an ever-present help in time of need ”’
to many worthy students. All the students were
“his boys,’ and to all he was counselor and
friend, and endearingly known as “ Prof Stock.”

Physically, he was tall and wiry, with a great
capacity for work, which he never shirked. He
was humorous, tactful, judicial, but outspoken;
always sunny, hopeful, sane; of the right makeup
to lead and teach young manhood. He sprang
from the plain people and believed in them; thus
he naturally abhorred a plutocracy and believed
in every man’s having a fair chance.

It is thought that he did as much to advance
the cause of agricultural education and to popu-
larize the chemistry of plant foods as any one man
of his time. It was while he occupied the chair
of professor of agriculture that he evolved the
Stockbridge principle of plant feeding and the
Stockbridge formulas which he freely published
to the world, and which have made his name a
household word in rural communities.

THE STOCKBRIDGE PRINCIPLE
OF PEANT FEEDING

If I were asked what was Professor Stock-
bridge’s greatest contribution to agriculture, I
should say that it was not his formulas for crop
feeding by which he is so widely known; for,
useful as these were, they were but stepping
stones to a better knowledge of the object and
use of fertilizers. His greatest contribution to
agriculture, as it seems to me, was his new con-
ception of the office of fertility in farm economy.
Up to the time of the publication of the Stock-
bridge formulas, the practice had been to manure
the sowl in order to restore lost fertility and to
supply deficiencies in the soil, as ascertained by
a chemical or crop analysis of the soil. Stock-
bridge saw that this method was not a practical
solution of the problem, for neither chemical
nor crop analysis of the soil could be relied upon
as a true guide to its enrichment. The chemist
disclosed too much that was misleading and the
crop too little that was conclusive. But, what
is more to the point, Stockbridge saw that we
had taken hold of the problem at the wrong end.

A PRACTICAL SOLUTION

It was not the soil, but the crop, that we should
first consider. We should study it and its needs,
and supply it, as far as we were able, with the
necessary elements of plant nutrition by the

FEED THE PLANT — NOT THE SOIL

use of properly balanced manures. In a word,
he turned from the inert soil, which could not
answer, to the living crop, which could, and put
this question to it:

“What shall I supply you in excess of what
you may obtain from the soil or air by your own
habits and conditions of growth to make you
a perfect and profitable crop? ”’

On the other hand, the farmer was asking him:

“What shall I use to produce profitable crops
— how much and in what form?”

Starting, then, from the crop, with the farm-
er’s question ever spurring him on, and with
such data as he could find, he worked out his
well-known formulas, which were published
broadcast in 1876. And let me say here that
besides being published in many agricultural
papers and reports, more than half a million
pamphlets containing them were distributed.

FORMULAS NOT INFALLIBLE

He did not claim that his formulas were
infallible, for he anticipated and announced,
what we soon discovered in practice, that they
would need to be modified, as experience should
point the way. They served, however, a greater
purpose even than Stockbridge dreamed at the
time — they centered our thought and our
study on the crop. From that time on we dis-
cussed plant food and not soil food — plant feed-
ing instead of soil manuring. ‘‘ Feed the crop
rather than the soil’”’ was a frequent expression
at that time.

It is well to observe here that crop formulas
were not new. Ville and others had published

THE FIRST DEFINITE METHOD

various sets. The Stockbridge formulas, how-
ever, were unique in this: that they were based
not alone on the analysis of the crop, but on
its power of absorption from all the sources of
fertility —from soil, air, and water. Thus
Stockbridge boldly prescribed:

“To produce fifty bushels of shelled corn per
acre (without any stable manure) and its natural
proportion of stover, more than the natural
yield of the land, apply so many pounds each of
nitrogen, potash, and phosphoric acid. Or, to
produce a stated quantity of tobacco leaf of
the desired color and texture, apply a stated
quantity of plant food elements, preferably in
the form of sulphates and nitrates.”’

Here, then, for the first time, a definite way was
prescribed to attain a definite object. It was a
startling proposition, and, as might be expected,
it brought ridicule from many quarters, but
Stockbridge did not allow that to disturb him.
He knew that the commercial farmer needed a
tangible starting point. He knew that to con-
sider the needs of the crop, the living thing, both
as to amount and kind of plant food, rather than
the needs of the soil, an unknown and unknow-
able quantity, was not only a common-sense way
of meeting the problem of plant nutrition, but
a very direct way of helping the farmer out of
the quagmire of doubt.

INSURE THE CROP

The formulas might not be accurate; in some
cases they might supply excessive amounts of
plant food elements and apparently be very
wasteful, yet he believed that in the end it was

STUDY THE PLANT

better economy to apply too much and insure a
crop than use too little and lose a crop. Never-
theless, as Professor Stockbridge anticipated
would be the case, the fertilizers based on his
formulas were modified from time to time as we
gained light, chiefly by the reduction of nitrogen
and the increase of phosphoric acid, as it was
found that many crops were able to gather
from natural sources, through bacterial action or
otherwise, some part of the required nitrogen,
and that an excess of available phosphoric acid
would hasten maturity. It was also found that
to supply the full complement of nitrogen in
addition to what the crop would assimilate for
itself tended in many cases to produce an un-
balanced growth; yet, on the other hand, it
was found that in some cases, especially where
a forced growth or a tender leaf was required,
an excess of nitrogen was desirable. Thus it
will be seen that the crop was both the starting
and the objective point. Not only its chemical
needs, but its habits and conditions of growth,
the object for which it was grown, and its
market qualities, were all factors which influ-
enced the composition or modification of the
fertilizers; and the same factors are as potent
to-day. Thus, since it was the crop that chiefly
concerned Professor Stockbridge, how natural
and sensible was his question: ‘‘ What shall I
supply you to make you a perfect and profitable
crop:
POTENTIAL FERTILITY

Let us now consider for a moment another
phase of the subject, namely, the potential

THE PLANT FOOD IN THE SOIL

6c

fertility of the soil, or “‘ the natural yield,” to
which Professor Stockbridge frequently referred.
It has been known for a long time that practically
all tillable soils are rich in plant food elements,
and yet many of them are barren, and most of
them will not produce profitable crops without
the aid of manure or fertilizer.

Prof. Frederick D. Chester, of Delaware, states
in an able bulletin recently published:

‘““ An average of the results of 49 analyses of the typi-
cal soils of the United States showed per acre for the
first eight inches of surface 2,600 pounds of nitrogen,
4,800 pounds of phosphoric acid, and 13,400 pounds of
potash. The average yield of wheat in the United States
is 14 bushels per acre. Such a crop will remove 29.7
pounds of nitrogen, 9.5 pounds of phosphoric acid, 13.7
pounds of potash.

“Now, if all the potential nitrogen, phosphoric acid,
and potash could be rendered available, there is present
in such an average soil, in the first eight inches, enough
nitrogen to last ninety years, enough phosphoric acid
for five hundred years, and enough potash for one
thousand years.”’

In a word, potential fertility represents plant
food which is so tightly locked up that it is not
available for present needs and becomes avail-
able only through the process of decay and
disintegration, which is too slow to meet the
requirements of the commercial farmer. Stock-
bridge realized the situation, but instead of
asking the soil how much of the potential fer-
tility could be depended upon for each crop (a
question which will never be satisfactorily
answered), he went to the crop and asked it how

THE VERY SMALL AMOUNT REQUIRED

much it was necessary to supply for a stated
yield over and above the natural yield of the
land. In all cases he found it to be a very small
quantity. For the corn crop, not over 200
pounds of nitrogen, potash, and phosphoric acid
was necessary, which the crop would return
fiftyfold (at least five tons in stalk and grain),
so little to produce so much, and yet, if this little
quantity of 200 pounds was not supplied, the
crop would be a failure.

THE LITTLE ESSENTIAL BALANCE

It was this little essential balance of available
plant food which stood between success and
failure that concerned Professor Stockbridge, as
it concerns every farmer to-day. Although it
was small, he did not deem it wise to depend
upon the potential fertility of the soil to supply
it, or even any considerable part of it. For the
commercial farmer it was too risky and uncertain.
To insure a crop, as far as one was able, was a
cardinal principle with him; not to do it was, in
his eyes, almost a crime. But he felt that all
these things would right themselves as we came
to know more about farm crops and _ their
environment.

THE SINGLE ELEMENT DOCTRINE

As bearing on the economy of his system of
plant feeding, | want to quote here one of his
apt illustrations. He said in effect:

“In a sense the farmer is a manufacturer and the soil
is his machine, into which he puts plant food, and out
of which, by the aid of nature and his own efforts, he

THE SINGLE ELEMENT DOCTRINE

takes his product at harvest time. If the soil machine
is a good one, so much the better. If it has a balance of
crop-producing power to its credit, let us preserve that
balance for an emergency. Let us not draw on it for
present needs.”

He had no patience with the so-called szngle-
element doctrine, which depends for its success
on the potential fertility — no patience with the
farmer who was trying to find out for himself if
he could leave out any one of the three leading
elements of plant nutrition (nitrogen, potash,
and phosphoric acid), or how little of each he
could get along with. That was a proper subject
for the scientific worker to investigate, but until
we knew more about it, the practical farmer, who
had his living to make and bills to pay, should
not tinker with it. To Stockbridge it meant, in
the end, improvident farming. At best, the
farmer had to take great chances, especially with
the weather, — the largest factor in crop raising,
over which he had no control, — but he should
take no chances with the things which he could
control. Among these were the amount and
kind of manure which he applied to his crops.
Thus, if he hoped for a stated crop he should at
least fertilize intelligently for that crop. For
the man who was dependent on his crops any
other course was unwise. Moreover, any other
course would leave the soil machine in a poorer
condition than he found it. Broadly speaking,
to encourage him to take out more than he
put back was not only bad economy, but bad
morals, and should be discouraged, for in the
end it would lead to crop bankruptcy.

DIFFERENT FORMS OF PLANT* FOOD

RAISING THE STANDARD

It is needless to say that the farmers appreci-
ated this bold course. As Stockbridge put it,
they jumped on his wagon before he was ready
to start. He was indeed their prophet, who led
them out of the wilderness of speculation into
the light of practical methods. As might be
expected, this new conception of the use of
chemical manures — or plant food, as he liked
to call it—not only revolutionized all our
notions of fertilization, but the entire fertilizer
business as well. It immediately raised the
standard of commercial manures from ordinary
superphosphates, containing no potash, to
‘“complete manures,” many of them rich in
potash. Special fertilizers for special crops or
classes of crops were brought out by various
makers, and the business received a new impetus
and a new recognition in the community. It
was put on a sound footing, from which it can
never be displaced.

STOCK FEEDING AND PLANT FEEDING

As in stock feeding we chiefly concern our-
selves with the study of the animal and its needs,
so in plant feeding we must make an intelligent
study of the needs of the living crop. As we know
how to feed the cow for milk or beef, so we must
know how to feed the plant for leaf or seed.
Not only must we know the amount of plant
food to be supplied, based on crop requirements,
but the form and association of the different
elements must be considered; and in the study
of this problem we must also continue to study
the soil, its potential fertility, its physical and

10

CONTINUAL STUDY NEEDED

chemical characteristics, and particularly the
lower orders of life which it contains, the bacteria
and other unseen forces. In short, we must
continue our study of all the sources and forces
of fertility, to the end that we may know what
each contributes to the upbuilding, not neces-
sarily of the soil, but of the crop life above the
soil. Thus did Stockbridge teach and practice.

GOOD PRACTICE AND GOOD SCIENCE

As Stephenson made practical the discovery of
Watts, as Singer improved upon the invention
of Howe, so Stockbridge took the teachings of
Liebig and Johnson, the tables of Wolf, and the
experiments of Goessmann, Atwater, and Sturte-
vant, and applied them to practical and useful
ends. While the system of plant feeding which
he employed, or perhaps I should say, the
method of application as prescribed in_ his
formulas, did not appeal to the scientific mind
in the beginning, it did appeal to the practical
farmers, for it met their needs as no other
method ever before had done. As good practice
and good science must agree in the end, so I
believe the scientific world is coming to agree
with the practical farmer that the system and
the method of application for which Stockbridge
stood and labored is as truly scientific as it is
thoroughly practical, and to accord him a high
place among the workers for the advancement of
scientific as well as practical husbandry.

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