Press Bulletin No. 57.
flORiDA AIl( IULTUlAL LXP[flliMNT STATION.
(E. R. FLINT.)
PROPOSED EXPERIflENTS ON
FERTILIZATION OF THE ORANGE.
While Florida justly and easily holds first place as to the
quality of her oranges, there are many groves that can.be im-
proved both as regards quality and quantity. The value'of
the orange crop is a very considerable one to the State, and any
means that can be demonstrated to improve the size, quality
and yield would be worth far above the cost of the experiment.
But few systematic experiments have been conducted in this
line, and these, as a rule, for such a short time that no definite
conclusions can be reached. Such experiments, to be success-
tul, should extend over a sufficient number of years to elimin-
ate the element of variation due to the yearly fluctuation in
the crop from natural causes. That such an extended experi-
ment would not be undertaken by private individuals is natu-
ral, as the money value of the crop is the essential thing, and
it is not to be expected that an individual would care to devote
his income-bearing grove to the solution of the question. The
Station has, therefore, planned a series of experiments on this
line which it is hoped may be continued sufficiently long to
demonstrate the best sources and the most profitable amounts
of plant food to apply, in order to produce the largest quantity
consistent with the highest quality of fruit.
The present method of fertilizing the orange is the result
of many years of practical experience, and is, to a considerable
extent, satisfactory. Some points have been definitely settled,
such as the injurious effect of organic nitrogen, except in very
limited amounts, and also chlorides on the quality of the fruit.
Sept. 11, 1905.
2 PRESS BULLETIN No. 57.
These points, then, can be left out of the plan of the experi-
It would perhaps have been preferable, in some respects,
to have started such an experiment on a grove newly set out,
where conditions could have been controlled from the begin-
ning, but in order to save the four or five years necessary to
bring such a new orove into bearing, one has ieen selected
which answers the conditions of the experiment fairly well.
For this purpose, the Station has secured the grove and co-oD-
eration of Mr. J. W. Oliver, of Kissimmee. This grove has
been more or less neglected in the past (before it came into the
present owner's hands). and yet is composed of young, healthy
trees, a larger part of which have begun to bear fruit. The
soil is a rather poor average one, on which the effect of the fer-
tilizers applied can be more readily determined than on a nat-
urally richer soil or one which has had previous liberal fertili-
As the Station desires to secure the interest and sugges-
tions of those interested .in orange growing, a plan of the expe-
riment is here outlined. I desire here to acknowledge the
courtesy and willingness to give their experience, which was
extended to me by numerous growers, while planning the ex-
The grove selected contains about 1,000 trees and has been
divided into 44 plots of 16 trees each with a row of trees be-
tween each plot in both directions, this latter precaution being
necessary on account of the distance to which the feeding
roots of the orange extend. With plots of this size it is con-
sidered that better average results can be obtained than by
experimenting on single trees. Nearly every plot contains
trees that are now bearing as well as those that will bear in a
year or two, and many of the plots contain one or more grape
fruit; yet, taken as a whole, the plots are quite even. Each
tree in the plot is numbered and the amount of fertilizer
applied will ne regulated according to its size and condition,
except that every non-bearing tree will receive the same fer-
tilizer for the present, until it comes into bearing. This fertil-
izer analyzes about-
Bearing trees yielding 10 boxes or less will receive, as a basis,
the equivalent of 201bs. a year of a fertilizer analyzing-
PRESS BULLETIN NO. 57. 3
N itrogen ................... ............. 4% ,
Phosphoric acid ..... .................. 6%,
Potash ......... .......... .............. 12% ,
given in threeiapplications, namely, one-fourth in June, one-
fourth in October, and one-half in February. As the yield in-
creases, the amount will be increased. It was first necessary
to establish a basis or standard by which to judge the effects
of the different fertilizers. This was finally decided as fol-
Nitrogen .............4% as sulphate of ammonia.
Phosphoric acid........6% as dissolved bone black.
Potash.......12% as high grade sulphate of potash.
The first question was the limit of profit of each ingredient
and plots 1 to 12 are devoted to this, receiving respectively:
Plot i1-The standard as given above.
2-Decreasing all ingredients one-half.
'" 4- the potash 14.
5- " .
6- phosphoric acid K.
1 7- 6 6 6 %.
8- nitrogen V.
9- 6. .
S10- phosphoric acid Y and potash Y4.
6 1, 16 6. 1/ .. .. &&
l1- / " */ Y.
12- 6 % M.
SOURCES OF NITROGEN.
Plot 13 receives its nitrogen as nitrate of soda.
Plot 14 receives its nitrogen M nitrate of soda, M sulphate
Plot 15 receives its nitrogen Y dried blood, sulphate of
Plot 16 receives its nitrogen Y dried blood, M sulphate of
ammonia, M as nitrate of soda.
Plot 17 receives its nitrogen as bone.
SOURCES OF PHOSPHORIC AOID.
Plot 18 receives its phosphoric acid as acid phosphate.
Plot 19 receives its phosphoric acid as acid phosphate with
low grade sulphate potash and nitrate of soda.
Plot 20 receives its phosphoric acid as steamed bone.
Plot 21 receives its phosphoric acid as dissolved bone.
Plot 22 receives its phosphoric acid as slag.
4 PRESS BULLETIN NO. 57.
Plot 23 receives its phosphoric acid as slag with low grade
sulphate of potash and nitrate of soda.
Plot 24 receives its phosphoric acid and nitrogen as cotton
Plot 25 receives its phosphoric acid and nitrogen as castor
Plot 26 receives Peruvian guano and low grade sulphate of
SOURCES OF POTASH.
Plot 27 receives its potash as low grade sulphate of potash.
Plot 28 receives its potash as low grade sulphate with acid
Plot 29 receives its potash as kainit.
Plot 30 receives its potash as tobacco stems.
Plot 31treceives its potash as wood ashes.
AMOUNT TO APPLY AND EFFECT OF EXCESS.
Plot 1 receives 201bs. per year.
32 401bs. "
33 501bs. "
34 801bs. "
Plot 35 receives the standard with a cover crop.
Plot 36 receives the standard with a cover crop, decreasing
Plot 37 receives the standard with lime.
Plot 38 receives the standard with heavy mulching of trees.
Plot 39 receives the standard in two applications.
Plot 40 receives the standard with most of the potash in
the June and October applications.
Plot 41 receives its potash. Y as low grade, M as high
Plot 42 receives its potash as carbonate of potash-mag-
Plot 43 receives its potash and nitrogen as nitrate of
Plot 44 receives the standard with salt.
After the experiment has been in operation sufficiently
long to establish the effect of the fertilizer applied on the qial-
ity of the fruit, this point will be controlled by laboratory
tests. The yield of each tree will be noted every year.
glSTATH PAPERS PLEASE COPY.