• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Table of Contents
 Plan of experiment
 Composition of tank soils
 Composition of drainage water from...
 Loss of plant food from unfertilized...
 Loss of plant food from fertilized...
 Conclusions






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 132
Title: Loss of fertilizers by leaching
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027516/00001
 Material Information
Title: Loss of fertilizers by leaching
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 20 p. : charts ; 23 cm.
Language: English
Creator: Collison, S. E ( Stanley E )
Walker, Seth S ( Seth Stetson ), b. 1886
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1916
 Subjects
Subject: Soils -- Leaching   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Stanley E. Collison and Seth S. Walker.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027516
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000922745
oclc - 18161637
notis - AEN3254

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Plan of experiment
        Page 3
    Composition of tank soils
        Page 4
    Composition of drainage water from unfertilized soil - parts per million
        Page 5
    Loss of plant food from unfertilized soil
        Page 6
        Loss of plant food from one acre
            Page 7
        Loss of nitrogen
            Page 7
        Loss of phosphoric acid and potash
            Page 8
    Loss of plant food from fertilized soil
        Page 9
        Factors influencing loss of nitrogen
            Page 10
            Page 11
        Loss of nitrogen
            Page 12
            Page 13
        Loss of potash
            Page 14
            Page 14a
            Page 14b
            Page 15
            Page 16
        Loss of other constituents
            Page 17
        Change in composition of soil
            Page 18
    Conclusions
        Page 19
        Page 20
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





Bulletin 132 November, 1916

UNIVERSITY OF FLORIDA

Agricultural Experiment Station





LOSS OF FERTILIZERS BY LEACHING

STANLEY E. COLLISION
AND
SETH S. WALKER


-g...Ci-u-t-~~e i =oil tak


Fig. 1.-Citrus trees in soil tanks


The Station Bulletins will be sent free upon application to the Experiment
Station, Gainesville.



















BOARD OF CONTROL

P. K. YONGE, Chairman, Pensacola, Fla.
T. B. KING, Arcadia, Fla.
E. L. WARTMANN, Citra, Fla.
W. D. FINLAYSON, Old Town, Fla.
F. E. JENNINGS, Jacksonville, Fla.
J. G. KELLUM, Secretary, Tallahassee, Fla.




CONTENTS
Page
Plan of Experiment ...........----.. --------------- -------- 3
Composition of Tank Soils-......................---------------- -------------- 4
Composition of Drainage Water from Unfertilized Soil ...........................--- 5
Loss of Plant Food from Unfertilized Soil......................----------------.---. 6
Loss of Plant Food from One Acre..----------.........................----------- 7
Loss of Nitrogen .....------------............................ ------ ---------- 7
Loss of Phosphoric Acid and Potash.............-.-------.......... 8
Loss of Plant Food from Fertilized Soil------------..............--......-------- 9
Factors Influencing Loss of Nitrogen..........----............--------...... -- 10
Loss of Nitrogen ....................-- ------- ----------..... 12
Loss of Potash --------- --......................-------........... 14
Loss of Other Constituents ................----------.... 17
Change in Composition of Soil--------......------............... ...................... 18
Conclusions .. ......----------............---...... ------ 1











LOSS OF FERTILIZERS BY LEACHING


Cultivated soils are subject to two main losses of fertility,
the plant food contained in the crop removed and that leached
out of the soil by rain and carried to depths of soil below the reach
of plant roots. The amount of plant food removed by different
crops is well known; that lost through leaching is not so definitely
known. Knowledge of which elements of plant food are lost in
the largest amounts through leaching is also inadequate.
The work reported here was undertaken to obtain definite
information as to these losses under Florida conditions. This
work was begun in 1910. It was planned and started by A. W.
Blair, formerly chemist to the Florida Experiment Station.

PLAN OF EXPERIMENT
To obtain an accurate knowledge of the total amounts of
plant food lost from the soil, an equipment must be used by means
of which all the water leaching through a unit mass of soil can
be collected and analyzed. Accordingly, in this work, large steel
tanks were sunk in the soil to within about three inches of the
rims. These were filled with soil taken from the place on the
horticultural grounds of the Experiment Station, where the tanks
were sunk. Each tank was provided with an opening in the bot-
tom, to which was fitted a drainage pipe. Four such tanks were
placed about a central collecting pit into which the drainage pipes
extended. Thus any excess rainfall above that which the soil ..-
could hold would percolate through the layers of soil in the tanks
and appear in the drainage pipes where it could be collected,
measured, and analyzed from time to time.
With such an outfit the total amount of plant food leaching
through the soil could be determined. At the same time light
would be thrown on the question as to which of the important
plant food constituents were lost in the largest amounts. The
tanks used were four feet deep with a surface area of approxi- v
mately one two-thousandths of an acre.
The analysis of the soil used in the tanks is given in Table 1.
This soil is a rather coarse gray sand of high hammock type and
classified by the Bureau of Soils as Norfolk sand.






Bulletin 132, Fertility Leaching


TABLE 1
Composition of Tank Soils
Expressed In Percentage
Tank 2 Tank 4
Inches 0-9 9-21 |21-33133-451 0-9 9-21 121-33133-45
Silica (Si02) ........-93.82 94.59 95.70 96.50 94.32 96.26 96.29 96.51
Phosphoric Acid
(P205) ................ .085 .083 .072 .073 .114 .088 .083 .067
Potash (K20) .......- .039 .036 .051 .032 .055 .039 .040 .032
Soda (Na20) ....... .107 .193 .209 .403 .147 .154 .184 .228
Lime (CaO) ........ .295 .315 .305 .325 .325 .245 .245j .135
Magnesia (MgO) .129 .074 .063 .071 .303 .241 .2451 .230
Iron and Alumina
(Fe2 03. A12 03) .760 .942 1.343 1.252 1.551 1.507 1.552 1.708
Sulphur Trioxide
(S 3) ................ .053 .024 .0271 .029 .012 .019 .015 .022
Nitrogen (N) ....... .054 .022 .013 .009 .054 .023 .013 .009
Humus .----...---...- .64 .41 .46 .32 .64 .51 .38 .35
Loss on Ignition... 3.11 1.93 1.97 1.22 3.27 1.96 1.62 1.24

The tanks were exposed to the rainfall July 7, 1910, and all
of the water leaching through was collected and measured. Rep-
resentative samples were taken from time to time and analyzed.
In the spring of 1911 a budded orange tree (Valencia late on sour
Stock) was placed in each tank and the trees were fertilized as
follows:
The tree in tank 1 received sulphate of ammonia, acid phos-
phate and high-grade sulphate of potash.
The tree in tank 2 received the same, and beggarweed was
grown in the tank during the rainy season.
The tree in tank 3 received the same treatment as that in
tank 1, except that nitrate of soda was substituted for sulphate
of ammonia.
The tree in tank 4 received the same treatment as that in
tank 1, except that dried blood was substituted for sulphate of
ammonia.
The standard formula used in the citrus field experiments
of the Department of Chemistry of the Florida Agricultural
Experiment Station was used. (Fla. Agrl. Exp. Sta. Annual
Report 1909, p. xxvi.) This consists of 5 per cent ammonia, 6
per cent phosphoric acid and 6 per cent potash. In the fall the
ammonia was reduced to 21/2 per cent, and the potash increased
to. 8. The equivalent of two pounds of this mixture was given
each tree three times a year. Thus the actual amount of nitro-
gen, phosphoric acid and potash received by each tree was the
same, the only difference in the treatment being that the source
of the nitrogen varied.









Florida Agricultural Experiment Station


TABLE 2

Composition of Drainage Water from Unfertilized Soil-Parts Per Million


Date
of
Sampling






Aug. 1910
A u u ........
Aug. 15........
A"g. 24 ....
Sept. 8 .......
Oct. 10 ........
Oct. 19 ......
Nov. 29 ....
Jan.11, 1911
Mar. 15 .......
May 23 .......


Aug. 1, 1910 108.2
Aug. 10 .... 76.8
Aug. 15 .... 63.7
Aug. 24 .... 89.6
Sept. 8 ........ 99.8
Oct. 10 ........ 69.8
Oct. 19 ........ 103.9
Nov. 29 .... 106.3
Jan. 11, 1911 102.2
March 15 .... 37.5
May 23 ....... 95.6


Aug. 1, 1910 107.2
Aug. 6 ........ 78.1
Aug. 15 .... 66.4
Aug. 24 .... 91.7
Sept. 8 ........ 97.7
Oct. 10 ........ 79.7
Oct. 19 ........ 106.7
Nov. 29 .... 106.6
Jan. 11, 19111 100.8
Mar. 15 .... 68.1
May 23 ....... 102.9


\ug. 1. 1910! 110.4
Aug. 6 ........ 67.3
Aug. 15 ... 61.2
Aug. 24 ... 87.0
Sept. 8 ... 95.5
Oct. 10 ..... 71.0
Oct. 19 ...... 109.3
Nov. 29 ....105.7
Jan. 11. 19111 100.9
March 15 .... 29.6
May 23 ........ 91.0


It-.


-Ca 1't Q.l0
o 0t.


38.0
69.3
72.0
50.5
34.3
15.7
16.6
18.2
18.4
16.8
13.9


28.4
55.0
67.3
60.7
26.9
14.2
16.9
19.7
20.4
19.5
12.6


41.7
83.5
74.2
41.9
23.2
15.2
16.9
18.6
S19.7
11.7
9 0


63.5
114.3
125.6
64.4
21.0
18.1
24.1
31.5
23.6
16.7
16.1


----


ci

.O 5
*l 0 M

o a
to tomm


0
O





Tank 1
7.28 49.8
3.40 77.8
3.12 79.0
2.49 53.4
1.92 38.6
1.57 19.7
1.32 16.6
1.10 17.9
.92 17.5
.54 19.5
1.02 16.8

Tank 2
7.10 | 44.2
3.27 71.6
2.81 87.5
2.63 74.9
1.40 35.7
1.30 19.9
1.04 20.9
1.04 23.2
.88 23.0
.50 26.3
1.13 17.8

Tank 3
7.01 46.2
3.83 79.3
3.36 71.9
2.21 42.1
1.73 21.6
1.61 14.9
1.44 15.3
1.66 17.0
1.58 17.4
.57 14.6
1 32 10.9

Tank 4
11.07 50.5
9.08 I 78.6
9.24 93.4
5.30 I 45.2
4.11 1 22.2
4.40 19.4
4.46 21.9
4.12 27.2
3.46 24.2
1.58 20 2
2.84 16.7


34.7
57.0
61.3
39.8
28.0
15.0
14.2
13.6
14.3
15.1
13.6


11.57 129.8
4.40 50.9
3.14 36.6
3.06 22.0
2.80 14.1
4.68 8.8
3.37 5.1
3.06 5.2
3.80 5.6
3.95 5.7
4.20 6.9


9.47 81.3
4.66 26.1
4.14 19.5
2.74 16.6
2.76 9.1
3.47 5.4
2.32 4.2
3.08 4.6
2.99 4.9
2.59 5.7
2.60 4.6


6.71 ] 59.8
2.96 29.0
2.32 [ 22.3
2.29 18.0
2.11 6.8
2.32 5.5
1.28 4.3
1.76 4.0
1.73 4.
1.91 4.8
2,26 4.3


13.70 79.8
5.47 37 5
4.38 31.0
9.73 17.4
33.09 8.0
42.24 5.3
30.53 4.9
19.46 5.1
17.22 5 9
19.09 5.0
18.09 4.0


26.4 59.8
33.2 30.1
42.5 33.6
33.2 32.4
16.8 11.9
10.0 12.1
10.5 7.6
10.4 8.8
11.0 6.9
11.9 3.8
9.1 5.4






Bulletin 132, Fertility Leaching


LOSS OF PLANT FOOD FROM UNFERTILIZED SOIL
As stated previously the trees in the tanks were first ferti-
lized in March, 1911. This gave a period of about a year, begin-
ning July 7, 1910, and ending in March, 1911, during which the
water collected contained only the plant food leached from the
natural unfertilized soil. The analyses of the water during this
preliminary period are given in Table 2 and are expressed in
parts per million of water. The dates on which the samples
were collected are also noted.
In looking over Table 2 the large loss of nitrogen as com-
pared with that of the other fertilizing materials will be noted at
once. The losses of phosphoric acid and potash are extremely
small in comparison. While the average loss of nitrogen for the
entire period amounts to 34.1 parts per million, the average for
phosphoric acid is only 0.11 parts per million and for potash 3.1
parts. It is apparent that nitrogen is lost from the unfertilized
soil in much larger quantities than any of the other important
plant food constituents.
It will be noted that the largest loss of the sulphate, chlo-
rine, potash and soda occurs in the first sample collected, after
which there is a gradual decrease in the amounts coming through.
This appears to be due to the fact that the soil had been newly
cleared and had received very little rainfall until after it had
been placed in the tanks. There was, therefore, considerable
soluble material present which immediately leached out as soon
as the heavy July rains began to percolate through it. Much of
this soluble material appeared in the drainage collected August 1;
after which the soil, being largely depleted of soluble matter,
gave up gradually decreasing amounts in the drainage. Another
point which should be mentioned here is that some of the brush
and Wood had been left on the land and burned.there. The sol-
uble matter in the ashes would appear largely in the first drain-
age water to leach through.
With the phosphoric acid, lime and magnesia, there is an
increase of these in the drainage from the first to the second
and in some cases, the third sample, and then a gradual decrease.
The indications are that this increase and decrease (correspond-
ing to similar fluctuations in the case of nitrogen) are due to the
action of bacteria on the organic matter with the consequent
formation of nitric acid and carbon dioxide. Both of these acids
would act on the mineral matter, changing it to soluble forms
which readily leach out. After a time that portion of the min-






Florida Agricultural Experiment Station


eral matter most easily acted upon by these acids would be
leached out, thus causing a decrease in subsequent samples of
drainage. Probably smaller amounts of these acids would be
formed later, which fact would also lead to the same result.
Again referring to Table 2 a gradual decrease in the amount
of nitrogen appearing in the drainage after August 15, will be
noted. This is evident with all four of the tanks and indicates
that after a time the greater part of the soluble nitrogen was
leached out, leaving the remainder in the form of insoluble
organic nitrogen. This form of nitrogen gradually becomes sol-
uble through nitrification, thus causing a steady but decreasing
loss as time goes on.
The large loss of nitrogen at the beginning of the experiment
proves again the well known fact that the aeration of the soil
by cultivation is an excellent means of increasing nitrification,
thus providing nitrogen in an available form for the growing
crop. It has been shown many times that cultivated soils contain
appreciably more nitrates than uncultivated soils under similar
crop conditions.
LOSS OF PLANT FOOD FROM ONE ACRE
In Table 3 the results for the more important constituents
shown in Table 2 are re-calculated to the acre basis in the form
of well known commercial materials. The nitrogen is calculated
in the form of nitrate of soda, carrying 18 per cent ammonia, and
the figures for this material represent the number of pounds
which would be required to make good the loss of nitrogen from
-an acre of soil under conditions similar to those found in the soil
tanks. The phosphoric acid is calculated as 16 per cent acid
phosphate; the potash as 49 per cent high grade sulphate of pot-
ash; and the lime as pure carbonate of lime (limestone).
TABLE 3
Plant Food (Expressed in Pounds of Fertilizer) Lost by Leaching from One
Acre of Unfertilized Soil in Ten Months
Tank 1 1 2 3 1 4 Average
Nitrate of Soda..................... 761.0 751.0 806.0 1094.0 1853
Acid Phosphate ..................... 2.8 2.5 2.6 3.7 2.9
Sulphate of Potash................ 20.6 18.7 21.6 45.2 26.5
Carbonate of Lime.................... 245.0 286.0 235.0 249.0 253.7
LOSS OF NITROGEN
This method of stating the results brings out more strikingly
the losses of the various materials. The great loss of nitrogen
is here especially prominent. A loss on the average of an amount






Florida Agricultural Experiment Station


eral matter most easily acted upon by these acids would be
leached out, thus causing a decrease in subsequent samples of
drainage. Probably smaller amounts of these acids would be
formed later, which fact would also lead to the same result.
Again referring to Table 2 a gradual decrease in the amount
of nitrogen appearing in the drainage after August 15, will be
noted. This is evident with all four of the tanks and indicates
that after a time the greater part of the soluble nitrogen was
leached out, leaving the remainder in the form of insoluble
organic nitrogen. This form of nitrogen gradually becomes sol-
uble through nitrification, thus causing a steady but decreasing
loss as time goes on.
The large loss of nitrogen at the beginning of the experiment
proves again the well known fact that the aeration of the soil
by cultivation is an excellent means of increasing nitrification,
thus providing nitrogen in an available form for the growing
crop. It has been shown many times that cultivated soils contain
appreciably more nitrates than uncultivated soils under similar
crop conditions.
LOSS OF PLANT FOOD FROM ONE ACRE
In Table 3 the results for the more important constituents
shown in Table 2 are re-calculated to the acre basis in the form
of well known commercial materials. The nitrogen is calculated
in the form of nitrate of soda, carrying 18 per cent ammonia, and
the figures for this material represent the number of pounds
which would be required to make good the loss of nitrogen from
-an acre of soil under conditions similar to those found in the soil
tanks. The phosphoric acid is calculated as 16 per cent acid
phosphate; the potash as 49 per cent high grade sulphate of pot-
ash; and the lime as pure carbonate of lime (limestone).
TABLE 3
Plant Food (Expressed in Pounds of Fertilizer) Lost by Leaching from One
Acre of Unfertilized Soil in Ten Months
Tank 1 1 2 3 1 4 Average
Nitrate of Soda..................... 761.0 751.0 806.0 1094.0 1853
Acid Phosphate ..................... 2.8 2.5 2.6 3.7 2.9
Sulphate of Potash................ 20.6 18.7 21.6 45.2 26.5
Carbonate of Lime.................... 245.0 286.0 235.0 249.0 253.7
LOSS OF NITROGEN
This method of stating the results brings out more strikingly
the losses of the various materials. The great loss of nitrogen
is here especially prominent. A loss on the average of an amount






Bulletin 132, Fertility Leaching


equivalent to 853 pounds of nitrate of soda in less than a year
is one to command attention.
The soil where this experiment was carried on was a virgin
soil, having been cleared but a few months before this work was
begun. In its original condition it supported a heavy growth
of forest trees, such as magnolia and oak, and a thick under-
growth, so that leaching was largely prevented. The leaf mold
present acted as a sponge, taking up much of the rainfall and
allowing it to percolate very slowly down through the soil. The
roots of the trees and undergrowth penetrated to every part of
the soil and were thus able to take up much of the water with
its dissolved plant food, evaporating it from the surface of the
leaves, retaining the dissolved matter, and consequently pre-
venting excessive leaching and loss of fertility. Under such
circumstances the conditions for rapid nitrification were not
especially favorable and much of the nitrogen remained locked
in the organic matter of the soil in an insoluble form. The por-
tion becoming soluble was largely utilized by the heavy forest
growth. When this growth was removed, conditions were
greatly changed. The soil became warmer. Moving it by cul-
tivation or other means brought about increased aeration, and
favorable conditions for rapid nitrification were established.
Although the soluble nitrates were thus being produced rapidly
there was no growing crop present to utilize them. So, on the
occurrence of heavy rains, they were largely leached out and
carried off in drainage. Practical farmers have observed that
newly cleared land will produce several good crops, but will in a
few years greatly deteriorate in productiveness unless legumes
and fertilizers are used. In such soils nitrification goes on very
rapidly, resulting in large losses of nitrogen and organic matter.
Keeping a growing crop on the soil as much of the year as possible
and increasing the supply of humus by turning under the vege-
table matter are the methods which would suggest themselves for
preventing such large losses of nitrogen as are shown in Table 3.

LOSS OF PHOSPHORIC ACID AND POTASH
The losses of phosphoric acid and potash given in Table 3
are very small when compared with that of nitrogen. The loss
of phosphoric acid calculated as acid phosphate amounts on the
average to only 2.9 pounds per acre. Such a loss is practically
negligible. This small loss, however, does not indicate any great
deficiency of phosphoric acid in the soil as the analysis in Table






Florida Agricultural Experiment Station


1 shows that the soil is fairly well supplied, containing consid-
erably more than many Florida soils. The phosphoric acid is
present in the form of insoluble compounds, which are but
slightly acted upon by the soil water, but the presence of a large
forest growth on this soil would prove that it became available
rapidly enough for the needs of this growth.
The average amount of potash, calculated as 49 per cent
sulphate, which was lost was less than 27 pounds per acre. This
small loss is due in large measure to the fact that potash is also
present in the soil in the form of insoluble compounds, which,
however, become slowly available for plant growth.

LOSS OF PLANT FOOD FROM FERTILIZED SOIL
In Tables 4 and 5 the losses of two of the most important
fertilizing constituents, the nitrogen and potash, are given for
the period during which fertilizers were applied to the tanks.
These losses in the drainage are given as percentages of the
actual total amounts of these two constituents added to the soil, '-
less the amounts already leached out up to the given date.
To state these losses in the same form used in Table 3 for the
unfertilized soil, would be misleading, since such figures would
show losses which under field conditions would be too large. It
is true that in practice the grower usually applies the fertilizer
in the grove only to that portion of the soil under the outer
branches of each tree and outward. The soil under the tree
receives no fertilizer and at times the middles receive none, so
that from a third to a half of the soil receives no fertilizer at all.
If we assume that a ton per acre is applied to a grove under
ordinary conditions, this ton is really applied to but a third or
half of the total acre, making the actual rate of application to
the soil receiving the fertilizer from two to three tons. The
amounts here discussed would be applied to good sized bearing
trees and would be larger than trees of the size used in this
experiment would receive. Consequently, to avoid over-empha-
sizing the losses found in this work they are stated as percent-
ages of the amounts applied. This gives a fair idea of the loss
which may be expected from Florida soils whether one ton or
more of fertilizer is used.
As mentioned heretofore, the losses shown in Tables 4 and
5 are stated in percentages of the total amounts of nitrogen and
potash applied in the fertilizers less the amounts lost on pre-
ceding dates. For example, in Table 4 on November 22, 1911,





Bulletin 132, Fertility Leaching


the drainage water from Tank 3 contained a quantity of nitrogen
equivalent to 54.21 per cent of the total amount of nitrogen
which had been applied up to that date, less the quantity of nit-
rogen already leached out up to the same date.
Since the loss of phosphoric acid remained extremely small
throughout the entire period, a similar table for this material is
omitted, as such a table would be made up of small fractions of
a per cent.
FACTORS INFLUENCING LOSS OF NITROGEN
The work here reported has shown that the amount of nitro-
gen which will leach through the soil is influenced by at least
three factors: first, amount and distribution of rainfall; second,
amount of growth made by the trees; third, source of nitrogen
used. A fourth factor which might be mentioned is the char-
acter of the soil. It is well known that soils containing consid-
erable humus or clay, or with clay lying near the surface, allow
less water to percolate through them, and are thus subject to
less loss of fertilizing constituents than soils composed largely
of sand. A coarse, sandy soil, such as was used in this work, has
but little power to hold water; in other words it soon becomes
saturated, and beyond this point any additional water will per-
colate through it and appear as drainage.
While the amount of annual rainfall has some influence on
the amount of drainage, its distribution is a more important fac-
tor. If the greater portion of rainfall occurs during the warm
months when the trees are making their growth, the evaporation
of moisture from the soil and from the leaves will take care of
much of the water entering the soil and the amount of drainage
will be comparatively small. If, on the other hand, heavy rains
occur during the cooler months, there is less moisture evaporated
from the soil, the trees being more or less dormant will take up
less, and as a consequence the drainage will be much larger.
Beginning with July 13, 1911, it will be observed that of the 27
collections of water, only 9 were made during the summer.
Without going into details in this connection it may be stated
that this was due to the rather unusual distribution of rainfall
during the last three or four years. More rain than usual oc-
curred during the fall and winter.
It was also found that there was a gradual decrease in the
amount of drainage water collected as the experiment continued.
This was due in large measure to the increase in size of the trees
occupying the tanks. Increased root and leaf growth would, of







Florida Agricultural Experiment Station


course, utilize more and more of the water and plant food. The
total rainfall in inches for five years, the amount of drainage in
inches and the percentages of rainfall which appeared as drain-
age are as follows:
Rainfall Drainage Percent
July 10, 1910 to March 11, 1911.................36...........................51
May 11, 1911 to April 12, 1912..............-..............45.......15.8........ 35
April 12, 1912 to April 12, 1913............ ..............60 ..... ..... .0 ......18
April 12, 1913 to April 12, 1914................... 49.......4. ...-- 12.7 ...........26
April 13, 1914 to April 17, 1915 .......... ....... 45.............12.4-........... 27
These figures bring out the point already mentioned, that
distribution of rainfall has an important influence on the amount
of drainage. In the third year the total amount of rainfall was
60 inches, yet only 11 inches, or 18 per cent of this appeared as
drainage, while in the fourth and fifth years, although the rain-
fall was considerably less, the drainage amounted to over an inch
more. More of the rainfall of the third year was held in the soil
and evaporated, thus decreasing the drainage, due to its more
even distribution through the year.

TABLE 4
Loss of Nitrogen in Percentages of Amount Applied Less Amount Already
Leached Out


Applicati


First.-----..-..--


Second....-..-


Third.........


Fourth..........

Fifth .-...--
"t
Sixth.............
Seventh--....

Eighth.......
Ninth.....-....
it


Tenth...........-
Eleventh......


Twelfth-..:...


Date of
on Sampling
Water
.....--. Mar. 15, 1911....
May 23........-
July 13................
..--- Aug. 23 -
Sept. 5 ......-..-....
Nov. 22...............
-.... Jan. 8, 1912........
Mar. 12........-.......
April 13 ............
------ June 10 ........
!July 16.....--.........
..... Aug. 23...............)
Oct. 21 ..-............-
...... April 1, 1913....
...-- July 14..........-....
Aug. 9 .........-.- I
...--- Oct. 31 ...............
........ Jan. 3, 1914........
Jan. 24 .............
Feb. 11..........
Mar. 6 ................
...-- Aug. 8 ...............
..... O ct. 10 ...............
Oct. 23................
Dec. 21 ...............
........Jan. 6, 1915......
Jan. 25-......--......
SApril 5...............
May 17................----


Tank
1

.. .. ....
1.70
1.59
6.39
12.40
10.35
8.13
6.05
10.34
10.96
5.55
2.92
0.52
1.00

1.28
0.80
0.27
0.28
0.38
0.94
1.11

0.81
0.77
0.69
0.51
0.35


Tank Tank Tank
2 3 4


3.94
5.78
4.75
15.24
17.06
7.07
4.22
9.68
12.19
3.50
1.36
0.07
0.60
2.16
3.15
0.36
0.15
0.30
0.28
1.37

1.80
1.24
0.99
1.04
1.28
0.64


6.12 3.94
15.63 5.68
33.28 17.34
54.21 A. 29.05
35.44 15.80
10.59 4.13
16.04 0.90
20.95 2.48
18.10 2.41
.... --. ..... ....
4.72 1.17
4.78 0.72
1.95 0.16

1.39 0.11
0.25 0.07
0.17 0.12
0.48 0.14
0.54 0.15
2.05 0.10
0.50 ..---....
...............- 0.08
0.92 0.14
0.59 0.08
0.64 0.16
0.34 0.14
- -................ .. -- -









Bulletin 132, Fertility Leaching


LOSS OF NITROGEN FROM FERTILIZED SOILS
Returning to Table 4 in which the loss of nitrogen is cal-
culated in percentage of the amount applied as commercial fer-
tilizer, it will be noted that, beginning with July 13, 1911, when
the nitrogen applied as fertilizer begins to appear in the drain-
age, there is a large and more or less continued increase in the
percentages lost up to November 22. This is true of all four of
the tanks, the greatest loss for any one period being 54.21 per
cent in the case of tank 3 between September 5 and November
22, 1911.
It should be remembered that tank 1 received sulphate of
ammonia as the source of nitrogen; tank 2, the same with beg-
garweed; tank 3, nitrate of soda, and tank 4 dried blood. For
the period from July 13, 1911 to July 17, 1913, tank 1 lost nitro-
gen equivalent to 40.1 per cent of the amount applied; up to the
latter date tank 2 lost 42.0 per cent; tank 3 lost 72.5 per cent;
and tank 4, 38.3 per cent. The trees in these tanks were prac-
,tically the same size when set and during the first year made
about the same amount of growth. The tree in tank 4, however,
gradually out-stripped the others in growth toward the end of
the year, which accounts largely for the somewhat smaller loss
of nitrogen in tank 4, as compared with tank 1.
The large loss of nitrogen from tank 3, nearly twice as much
as was lost from tank 1, is due to the great solubility of the
nitrate of soda in the soil moisture. Much of it was leached out
before the tree could take it up. To some extent the soil is cap-
able of holding or fixing the nitrogen of sulphate of ammonia as
long as it remains in the form of ammonia. Before the plant
can use the nitrogen of sulphate of ammonia and dried blood,
these materials must undergo the nitrification process, that is,
be gradually changed to the same form of nitrogen that is found
in nitrate of soda, and until this stage is reached their nitrogen
is less subject to loss than that of nitrate of soda. This rela-
tively slow process permits more nitrogen to be utilized by the
trees than in the case where nitrate of soda is applied to the
soil. These facts account largely for the much smaller loss of
nitrogen from these materials.
The data here presented bring out an important considera-
tion in the practical use of nitrogenous fertilizers. Nitrate of
soda should not be used to any large extent during the wet sea-
son. Nitrate of soda gives the best results when used in small
amounts at frequent intervals as a top dressing to a growing







Florida Agricultural Experiment Station


crop. When used in this way the crop will utilize a much larger
portion than in any other way. In a wet season or where it is
desired to give all the nitrogen in one application, sulphate of
ammonia should be preferred. In this experiment there are
indications that dried blood may become available somewhat more
rapidly than sulphate of ammonia, but further work must be
done before this is confirmed.
As a source of nitrogen to be used on a crop which has
become well established in the soil, any of these three materials
can be used with good results. This is brought out in the latter
part of Table 4. The figures here show that there is practically
no greater loss of nitrate of soda through leaching than there
is of sulphate of ammonia. Some variation in the growth of the
trees in the four tanks exerts an influence on the losses shown
in this part of the table.

TABLE 5
Loss of Potash in Percentages of Amount Applied Less Amount Already
Leached Out

Date of
Application Sampling Tank Tank Tank Tank
Water 1 2 3 4
F irst....................... M ar. 15, 1911.... ................ ......... .. ...............
May 23... ..... ...-... ...-- .- .... -.. ....
|July 13 .............. 0.18 0.37 0.55 0.73
Second... ........ Aug. 23...............- 0.09 0.37 0.64 0.46
"Sept. 5 .......... 0.64 0.28 1.11 0.74
'Nov. 22 ........... 1.20 0.74 2.15 0.74
Third........... .... 'Jan. 8, 1912........1 1.34 1.56 2.37 0.61
"Mar. 12........ ... 1.98 2.26 2.26 1.24
April 13 ............ 1.67 2.08 2.43 1.14
Fourth ......---... June 10 ........... 4.27 5.45 3.83 2.87
July 16... ........ 5.48 6.95 2.04 1.75
Fifth ......... .....- Aug. 23................ 4.19 2.51 ............. --......
S|Oct. 21 .............. 4.49 4.61 4.68 1.86
Sixth ..... .....--.-- April 1, 1913.... 2.30 1.99 2.11 1.94
Seventh .....-... IJuly 14 ............ 1.83 0.85 1.79 1.77
!" Aug. 9 ..---- I ........ 3.04 .............. -- ..
Eighth......... 'Oct. 31 ............ 2.50 6.98 4.08 0.73
Ninth...... ... Jan. 3, 1914........ 3.43 5.02 4.76 1.32
'Jan. 24 ...... 1.66 3.40 3.27 2.18
Feb. 11 .............. 1.58 2.15 2.57 2.79
Mar. 6 ........... 1.90 1.62 2.41 2.15
Tenth..... .... Aug. 8 ..... ...... 2.78 3.18 1 2.39 1.06
Eleventh....... Oct. 10 ............... 3.79 .... ..... 1.21 ...... .
O ct. 23 ......... ............... 4.22 ................ 0.69
Dec. 21 ............... 2.90 2.91 2.65 1.83
Twelfth................ Jan. 6, 1915 ........ 2.21 2.32 2.02 1.34
'Jan. 25 ............. 2.44 2.21 2.13 1.31
"April 5 .............' 3.08 3.01 2.57 1.97
May 17............... 1.85 2.60 ..-- .. ...






Bulletin 132, Fertility Leaching


In Table 7 there is given the percentage of loss for the entire
period during which the trees were fertilized as well as the num-
ber of gallons of water which were collected as drainage from
the four tanks. The smallest amount of drainage water came
from tank 4, in which the tree made the greatest growth.
LOSS OF POTASH FROM FERTILIZED SOILS
In Table 5 the loss of potash is calculated in the same way
as for the nitrogen in Table 4.
It should be remembered that high grade sulphate of potash
was used for all four tanks, so that differences in the amount lost
from them are largely due to the variation in growth of the trees,


TAiN K 1 /
NITROG N --
____POTAS_ -
IV/









Fig. 2.-Loss of nitrogen and potash during four years from tank 1


/ \
i \
TPNK 2 /
N TROE I


I I / \ \

O TA /


Fg -Los of nt e a
Fig. 3-Loss of nitrogen and potash during four years from tank 2


Fig. 3.-Loss of nitrogen and potash during four years from tank 2





Errata Sheet No. 1.-Figs. 2 and 3 are reprinted to correct the omission of
dates and weights.
July 1911 Mar. 1912 Nov. 1912 July 1913 Mar. 1914 Nov. 1914 May 1915


20

16 -

12

8

4
8 --- ^ ^



Fig. 2.-Loss of

July 1911 Mar. 1912


nitrogen and potash during four years from tank 1

Nov. 1912 July 1913 Mar. 1914 Nov. 1914 May 1915


\

I \
TPNK2 /

A I /
S/
--r- -7 -
,I I
II \
7 1 i7- -


/ ', \ .


T~lin 1 -C -f if-jfjn>2^ r t-ol 1*f r jk--T-n f--m *>^




Errata Sheet No. 2.-Figs. 4 and 5 are reprinted to correct the omission of
dates and weights.
July 1911 Mar. 1912 Nov. 1912 July 1913 Mar. 1914 Nov. 1914 May 1915




20 / -----/
TWNK 3/ '

16 \.A -- ---



















16
IV









12
,, ,d / -fo u e r\ f
Fig. 4.-Loss of nitrogen and potash during four years from tank 3
July 1911 Mar. 1912 Nov. 1912 July 1913 Mar. 1914 Nov. 1914 May 1915







16 -N'K------------
12 OTAH A/
12 / \-----~ -- -~







Fig. 5.-Loss of nitrogen and potash during four years from tank 4







Florida Agricultural Experiment Station


Fig i
/ I










Fig. 4.-Loss of nitrogen and potash during four years from tank 3


Fig. 5.-Loss of nitrogen and potash during four years from tank 4

and possibly to the action of the nitrogenous materials used. It
will be noted that the amounts of potash leaching through in-
creased as the experiment continued, which is just the opposite
to what was found true with the nitrogen. This fact which is
shown graphically in figures 2 to 5, where the losses of nitrogen
and potash for the four tanks are given in diagrams, is due to
certain differences in the behavior of nitrogen and potash in the
soil. Where a quantity of nitrogen in excess of the demands of
the growing tree is applied, the excess would appear largely
in the drainage water, as the soil has no power permanently to
hold nitrogen not taken up by growing plants. In the first part






Bulletin 132, Fertility Leaching


of the experiment more nitrogen was applied than could be util-
ized by the trees. Later on, however, the increased demands of
the new growth were asserted and toward the end all but a rel-
atively small portion of the nitrogen was apparently utilized.
These considerations do not apply to the behavior of potash.
In the early part of the work considerably more potash was ap-
plied than could be used by the trees, but owing to the power of
the soil to hold and fix potash, a considerable portion not used
remained permanently in the soil in the form of insoluble com-
pounds, which are but slowly available. As the work went on
and more potash was applied, a time arrived when the soil pos-
sessed no further capacity for fixing potash. In other words
the fixing power of the soil for potash had become exhausted in
taking care of previous applications, so that a large part of the
later additions leached through and appeared in the drainage.
These points are brought out in Table 6.
In Table 6 the time during which potash was added is divided
into four periods of approximately a year each. In the first col-
umn for each tank is given the number of grams of potash lost
during each of the four years. In the second column the loss
for each year is figured in percentage of the total amount applied,
less the amount leached out during previous years. It will be
noted that with the exception of tank 1, there is an increase in
percentages lost from the first to the third year. In the fourth
year the percentages drop to less than those in the third year.
It appears from these figures that during the first and second
years a portion of the potash applied was fixed in the soil. For
the third year there is a large increase in the amounts lost, indi-
cating that the capacity of the soil for holding potash was becom-
ing exhausted. The smaller loss for the fourth year appears to
indicate that the trees were using more of the potash than in
previous years.
TABLE 6
Loss of Potash by Years
Tank 1 Tank 2 i Tank 3 Tman 4-
Grams IPercent Grams IPercent: Grams Percent Gr.nmh Percent
May, 1911-April, 1912 11.01o 6.11 12.11 6.71 16.7 9.2 7.S 4.2
Apr., 1912-Apr., 19131 50.41 14.31 50.61 14.4' 31.7 9.21 21.01 5.9
Apr., 1913-Mar., 19141 55.41 .11.5 92.7 19.2' 82.2 16.6' 51.5 10.0
Mar., 1914-May, 1915! 99.71 16.41 99.0 17.41 67.9 11.4' 48.2 7.4

A better idea of the actual loss of potash may be obtained
by comparing the number of grams lost for the first two years






Florida Agricultural Experiment Station


with those of the last two. It will be noted that for tanks 2, 3,
and 4 the amounts lost in the last two years were three times as
much as in the first two years. In other words there was an
increased loss of more than 200 per cent. For the individual
tanks the increased loss for the last two years over that of the
first two years amounts in percentages, for tank 1 to 152; tank
2, 227; tank 3, 209; and tank 4, 242. These figures simply bring
out the fact already mentioned that while Florida soils of the type
used in this work have some power to hold potash, this capacity
is by no means unlimited, but soon becomes exhausted so that
further additions are easily lost.

TABLE 7
Loss of Fertilizers by Leaching in Percentages of Amounts Applied During
Period of Four Years
Tank I 1 2 3 4
Gallons of Water .-...- .............-. .......... ... 760 737 687 611
Nitrogen .......................................... .......... 22.8 25.9 32.5 15.1
Phosphoric Acid ........................ 05 .05 .03 .04
Potash ...................... ....................... ........ 29.8 35.0 27.4 17.7
LOSS OF OTHER CONSTITUENTS
Two other important constituents yet to be considered are
phosphoric acid and lime. The loss of phosphoric acid has re-
mained extremely small during the entire experiment. There
was practically no increase of this material in the drainage, even
after fertilizers had been applied for four years. It is evident
that the soil has the power to fix large quantities of soluble phos-
phates.
The facts here presented are worthy of consideration by all
practical citrus growers. High pine and hammock soils are as a
rule fairly well supplied naturally with phosphoric acid, and have
the power to hold large amounts of this material applied in the
fertilizer. It has been noted in the field experiments of the
Chemistry Department of the Florida Experiment Station that
when soluble phosphates were used on citrus trees for five years,
the content of phosphoric acid has increased as much as 30 to 50
per cent in the upper twelve inches of soil. In view of these
facts, it is therefore a pertinent question to ask whether many
growers who have been using 8 to 10 per cent of phosphoric acid
have not been applying considerably more than their trees could
possibly use. It should be recognized that nothing is gained by
applying large quantities of phosphoric acid with the idea that it







Bulletin 132, Fertility Leaching


will take the place of nitrogen or potash, since each of these con-
stituents has its definite function in the plant which cannot be
. performed by any other element.
The amount of phosphoric acid lost for the entire period of
the fertilizer experiment is given in Table 7.
The lime found in the drainage water comes partly from the
fertilizer and partly from the soil. The acid phosphate used, of
course, contains considerable lime in the form of phosphate and
sulphate. As evidence of the loss of lime by using fertilizers
which leave an acid residue in the soil, the amount of lime lost
from tanks 1 and 2 should be compared with that lost from tank
3. Tanks 1 and 2, receiving sulphate of ammonia, a material
which increases soil acidity, lost on the average 569 grams of
lime, while tank 3, receiving nitrate of soda which leaves a basic
residue in the soil thus tending to decrease the acidity, lost 242
grams of lime-only 42.6 per cent of that lost from tanks 1 and
2. The value of the nitrate of soda in thus conserving the lime
of the soil is clearly brought out by this comparison.

TABLE 8
Change in Composition of Soils Due to Fertilizer Treatment.
Pounds Per Acre
l Phosphoric
Tank J Nitrogen Acid Potash
1 Original ....--- ..--------- -.......... 2730 5877 2543
Fertilized .--...-.----. ---.... --..---------- 2191 8379 3941
Difference ...............-.............-..- ... 539 2502 1398
2 Original .......-....-............-- ...-- ..--- .. 2340 5877 2606
Fertilized .-....-.....------------.. 2030 9184 4277
Difference .-.................... ......--.... 310 3307 1671
3 Original .-------.. -- -.-----------.... 2500 5877 2636
Fertilized ..---..--------------- 1820 9023 3850
Difference ..........--..................-.... 680 3146 1214
4 Original ................................ .. 2540 6940 3300
Fertilized .... ............ ..... -2184 9905 5026
Difference .................. ........ 356 2965 1726

CHANGE IN COMPOSITION OF SOIL
The data in Table 8 bring out the change in composition of
the soils used in the tanks due to the fertilizer treatment. These
results are calculated to the acre basis and to a depth of twenty-
one inches. The amounts of nitrogen, phosphoric acid and pot-
ash in the soils in their natural condition and after being ferti-
lized for five years are given. It will be noted that the amounts
of nitrogen have decreased, notwithstanding the fact that nit-






Florida Agricultural Experiment Station


rogen has been applied for five years. There is a considerable
increase in potash, thus showing the capacity of this type of soil
for fixing this material. The increase in phosphoric acid is
large and ranges from 40 to over 50 per cent in the various
tanks. From the small amounts of this material appearing in
the drainage water, it appears that these soils have not yet
reached the limit of their capacity for holding it.

CONCLUSIONS

As a result of the five years work herein discussed the fol-
lowing conclusions appear justified. These apply only to Flor-
ida conditions and to soils similar in character to that used in
this experiment.
1. Newly cleared land when exposed to heavy rainfall soon
loses much of its fertility through leaching.
2. The fertility of the soil may be maintained by growing
legumes and applying fertilizers. Much of the loss may be pre-
vented by growing crops.
3. The greatest loss of fertility from unfertilized soils
occurs with the nitrogen which leaches through in considerable
quantities.
4. Nitrification of the soil organic matter, thus changing
the nitrogen to a form readily lost by leaching, proceeds rapidly
in cultivated soils under Florida conditions.
5. Phosphoric acid and potash are lost in small quantities
from the unfertilized soil, since they are present largely in insol-
uble forms.
6. Lime is lost in considerable quantity, thus bringing
about an acid condition in the soil.
7. When cultivated soils are fertilized with a complete fer-
tilizer, the element lost in largest amounts by leaching is nitrogen.
8. Nitrate of soda leaches more rapidly and in larger
amounts than sulphate of ammonia or dried blood.
9. Nitrate of soda should be used in small amounts at fre-
quent intervals and usually as a top-dressing.
10. Distribution of rainfall influences to a considerable
extent the amounts of the fertilizing constituents which leach
through.






20 Bulletin 132, Fertility Leaching

11. Soils similar to that used in this work have the capac-
ity for fixing large quantities of phosphoric acid applied in the
form of acid phosphate.
12. Such soils have the capacity for fixing considerable
potash, but this power is soon exhausted, and afterward relatively
large amounts of potash are lost through leaching.




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