• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Introduction
 Review of literature
 Experimental procedure
 Experimental results and discu...
 Summary
 Literature cited














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 430
Title: The significance and maintenance of nitrate nitrogen in Bladen fine sandy loam in the production of cabbage
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00015142/00001
 Material Information
Title: The significance and maintenance of nitrate nitrogen in Bladen fine sandy loam in the production of cabbage
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 22 p. : charts ; 23 cm.
Language: English
Creator: Volk, G. M ( Gaylord Monroe ), 1908-
Bell, C. E ( Charles Edward ), b. 1883
McCubbin, E. N
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1947
 Subjects
Subject: Cabbage -- Soils -- Florida   ( lcsh )
Cabbage -- Fertilizers -- Florida   ( lcsh )
Sandy loam soils -- Florida   ( lcsh )
Nitrates   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 22.
Statement of Responsibility: G.M. Volk, C.E. Bell and E.N. McCubbin.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00015142
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000925503
oclc - 18253545
notis - AEN6154

Table of Contents
    Front Cover
        Page 1
    Front Matter
        Page 2
        Page 3
        Page 4
    Introduction
        Page 5
    Review of literature
        Page 6
    Experimental procedure
        Page 7
        Page 8
    Experimental results and discussion
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
    Summary
        Page 21
    Literature cited
        Page 22
Full Text


Bulletin 430


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
GAINESVILLE, FLORIDA







THE
SIGNIFICANCE AND MAINTENANCE
OF NITRATE NITROGEN
IN BLADEN FINE SANDY LOAM
IN THE PRODUCTION OF CABBAGE

G. M. VOLK, C. E. BELL and E. N. MCCUBBIN






TECHNICAL BULLETIN







Single copies free to Florida residents upon request to
AGRICULTURAL EXTENSION SERVICE
GAINESVILLE, FLORIDA


March, 1947









BOARD OF CONTROL


J. Those. Gurney, Chairman, Orlando
N. B. Jordan, Quincy
Thos. W. Bryant, Lakeland
M. L. Mershon, Miami
J. Henson Markham, Jacksonville
J. T. Diamond, Secretary, Tallahassee




EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of the
University3
H. Harold Hume, D.Sc., Provost for Agricul-
ture
Harold Mowry, M.S.A., Director
L. O. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifield, M.S., Asst. Dir., Admin.
J. Francis Cooper, M.S.A., Editor'
Clyde Beale, A.B.J., Associate Editors
Jefferson Thomas, Assistant Editors
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Managers
K. H. Graham, LL.D., Business Managers
Claranelle Alderman, Accountants




MAIN STATION, GAINESVILLE


AGRONOMY

W. E. Stokes, M.S., Agronomist1
Fred H. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Agronomists
G. B. Killinger, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
H. C. Harris, Ph.D., Associate
Fred A. Clark, B.S., Assistant




ANIMAL INDUSTRY

A. L. Shealy, D.'V.M., An. Industrialist:'
R. B. Becker, Ph.D., Dairy Husbandmans
E. L. Fouts, Ph.D., Dairy Technologists
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarians
L. E. Swanson, D.V.M., Parasitologist
N. R. Mehrhof, M.Agr., Poultry Hush.3
G. K. Davis, Ph.D., Animal Nutritionist
R. S. Glasscock, Ph.D., An. Husbandman
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.'
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech.
Katherine Boney, B.S., Asst. Chem.
J. C. Driggers, B.S.A., Asst. Poultry Hush.
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
John S. Folks, B.S.A., Asst. An. Hush.


ECONOMICS, AGRICULTURAL

C. V. Noble, Ph.D., Agri. Economist1 s
Zach Savage, M.S.A., Associate3
A. H. Spurlock, M.S.A., Associate
n. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate

Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr. Statistician'
J. B. Owens, B.S.A., Agr. Statisticians


ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.'
R. B. French, Ph.D., Biochemist


ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist and Act-
ing Head of Dept.
H. E. Bratley, M.S.A., Assistant


HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
A. L. Stahl, Ph.D., Asso. Horticulturist
F. S. Jamison, Ph.D., Truck Hort.
Byron E. Janes, Ph.D., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. K. Showalter, M.S., Asso. Hort.
R. J. Wilmot, M.S.A., Asst. Hort.
R. D. Dickey, M.S.A., Asst. Hort.
Victor F. Nettles, M.S.A., Asst. Hort.
F. S. Lagasse, Ph.D., Asso. Hort.2


PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist
Phares Decker, Ph.D., Asso. Plant Path.
Erdman West, M.S., Mycologist and Botanist
Lillian E. Arnold, M.S., Asst. Botanist


SOILS
F. B. Smith, Ph.D., Chemist'1
Gaylord M. Volk, Ph.D., Chemist
J. R. Henderson, M.S.A., Soil Technologist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
C. E. Bell, Ph.D., Associate Chemist
L. H. Rogers, Ph.D., Associate Biochemist
R. A. Carrigan, B.S., Asso. Biochemist
H. W. Winsor, B.S.A., Assistant Chemist
Geo. D. Thornton, M.S., Asst. Microbiologists
R. E." Caldwell, M.S.A., Asst. Soil Surveyor
Wade McCall, B.S., Asst. Chemist
J. B. Cromartie, B.S.A., Asst. Soil Surveyor


1 Head of Department.
2 In cooperation with U. S. D. A.
3 Cooperative, other divisions, U. of F.
4 In Military Service.
I On leave.










BRANCH STATIONS


NORTH FLORIDA STATION, QUINCY

J. D. Warner, M.S., Vice-Director in Charge
R. R. Kincaid, Ph.D., Plant Pathologist
W. H. Chapman, M.S., Asso. Agron.
R. C. Bond, M.S.A., Asso. Agronomist
L. G. Thompson, Ph.D., Soils Chemist
Frank D. Baker, Jr., B.S., Asst. An. Husb.


Mobile Unit, Monticello

R. W. Wallace, B.S., Associate Agronomist



Mobile Unit, Marianna

R. W. Lipscomb, M.S., Associate Agronomist


Mobile Unit, Wewahitchka
J. B. White, B.S.A., Associate Agronomist



CITRUS STATION, LAKE ALFRED

A. F. Camp, Ph.D., Vice-Director in Charge
V. C. Jamison, Ph.D., Soils Chemist
W. L. Thompson, B.S., Entomologist
J. T. Griffiths, Ph.D., Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, M.S., Plant Pathologist"
J. E. Benedict, B.S., Horticulturist
B. R. Fudge, Ph.D., Associate Chemist
C. R. Stearns, Jr., B.S.A., Asso. Chemist
James K. Colehour, M.S., Research Chemist
T. W. Young, Ph.D., Asso. Horticulturist
J. W. Sites, M.S.A., Asso. Horticulturist
H Sterling, B.S., Asst. Horticulturist
J. A. Granger. B.S.A., Asst. Horticulturist
H. J. Reitz, M.S., Asso. Plant Path.
Francine Fisher, M.S., Asso. Pl. Path.


EVERGLADES STA., BELLE GLADE

R. V. Allison, Ph.D., Vice-Director in Charge
J. W. Wilson, Sc.D., Entomologist
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane
Physiologist
B. S. Clayton, B.S.C.E., Drainage Eng.2
W. D. Wylie, Ph.D., Entomologist
W. T. Forsee, Jr., Ph.D., Asso. Chemist
R. W. Kidder, M.S., Asst. An. Husb.
T. C. Erwin, Assistant Chemist
R. A. Bair, Ph.D., Asst. Agronomist
C. C. Seale, Asst. Agronomist
L. O. Payne, B.S.A., Asst. Agronomist
Russel Desrosiers, M.S., Asst. Plant Path.
N. C. Hayslip, B.S.A., Asst. Hort.


SUB-TROPICAL STA., HOMESTEAD

Geo. D. Ruehle, Ph.D., Vice-Director in
Change
H. I. Borders, M.S., Asso. Plant Path.6
D. O. Wolfenbarger, Ph.D., Asso. Ento.
R. W. Harkness, Ph.D., Asst. Chemist

W. CENT. FLA. STA., BROOKSVILLE

Clement D. Gordon, Ph.D., Poultry Geneticist
in Charge2


RANGE CATTLE STATION, ONA

W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Associate Agronomist
D. W. Jones, B.S.A., Asst. An. Hush.
E. R. Felton, B.S.A., Asst. An. Hush.


CENTRAL FLORIDA STATION, SANFORD
R. W. Ruprecht, Ph.D., Chemist in Charge
A. Alfred Foster, Ph.D., Asso. Hort.
J. C. Russell, M.S., Asst. Entomologist
Ben F. Whitner, Jr., B.S., Asst. Hort.

WEST FLORIDA STATION, MILTON
H. W. Lundy, B.S.A., Asst. Agronomist


FIELD STATIONS
Leesburg
G. K. Parris, Ph.D., Plant Path. in Charge

Plant City
A. N. Brooks, Ph.D., Plant Pathologist

Hastings
A. H. Eddins, Ph.D., Plant Pathologist
E. N. McCubbin, Ph.D., Truck Horticulturist

Monticello
S. O. Hill, B.S., Asst. Entomologist' *
A. M. Phillips, B.S., Asst. Entomologist'

Bradenton
J. R. Beckenbach, Ph.D., Horticulturist in
Charge
E. G. Kelsheimer, Ph.D., Entomologist
David G. Kelbert, Asso. Horticulturist
E. L. Spencer, Ph.D., Soils Chemist
Robert O. Magie, Ph.D., Hort., Glad. Inv.
Donald S. Burgis, M.S.A., Asst. Hort.

Lakeland
Warren O. Johnson, Meteorologist'

1 Head of Department.
2 In cooperation with U. S.
3 Cooperative, other divisions, U. of F.
'In Military Service.
6 On leave.







THE SIGNIFICANCE AND MAINTENANCE OF NITRATE
NITROGEN IN BLADEN FINE SANDY LOAM IN
THE PRODUCTION OF CABBAGE

G. M. VOLK, C. E. BELL and E. N. MCCUBBIN

CONTENTS
Page
Review of Literature .............-............-- .......... .. 6
Experimental Procedure .....................- ..................... 7
Experimental Results and Discussion ...................... 9
Sum m ary ................................-- .......-- ........... 21
Literature Cited ..................................- -........-...... 22

INTRODUCTION
The maintenance of available nitrogen in the mineral soils of
Florida is a critical problem in intensive crop production. Leach-
ing losses are usually high as a result of rapid decomposition of
organic residues and intensive seasonal rainfall. Such condi-
tions normally indicate that insoluble nitrogen supplements or
those in which leaching is retarded by the soil would be the most
economical. However, nitrate nitrogen has been found to be
desirable for top-dressing of rapidly growing crops, because the
fertilizer must penetrate rapidly to the root zone and be readily
available to the plants. It is preferred for part or all of the
nitrogen supplement used during the cool winter months when
the rate of conversion of other forms of nitrogen to the nitrate
form is slow. The use of this readily mobile form enhances the
danger of critical leaching losses.
Fertilizer practices for a given combination of crop and soil
should be based on fertilizer trials carried on until the response
to average seasonal climatic conditions is determined. Soil test-
ing may be an aid in establishing such practices, but alone is
not sufficiently reliable to justify changes in basic recommenda-
tions, especially with respect to those elements which, in the
absence of fertilizer supplement, are known to be deficient -for
intensive crop production.
There are conditions where seasonal variation from the nor-
mal makes it desirable to revise the recommendations for the
supplemental fertilization over and above the drill or basic ap-
plication. Theoretically, it should be possible to make a direct
evaluation of extremes of precipitation and temperature which
bring about this special requirement, but practically such evalua-
tion is difficult. Leaching loss of nitrogen is not a simple function







Florida Agricultural Experiment Station


of amount or intensity of rainfall, but a complex interrelation
between time, temperature, rainfall characteristics and soil con-
dition.
It was the purpose of this investigation to determine periodi-
cally nitrate nitrogen in Bladen fine sandy loam under various
fertilization practices with cabbage in the Hastings area, as an
aid in evaluation of such practices, and to determine the sig-
nificance of the level of nitrate nitrogen in the soil as a criterion
of nitrogen supply to the crop. A report on the horticultural
phase of this work, which includes an evaluation of the various
fertilizer trials for practical application, has been made by
McCubbin (6).1 A brief report on the first portion of the soils
phase of the study has been made by the senior author (9) and
will be reevaluated in this report in the light of the complete
investigation.
REVIEW OF LITERATURE
The leaching of soluble nitrogen from the soil is primarily
a function of the volume of percolation or gravitational- water
passing through the profile. Volk and Bell (11), using 1/2,000-
acre lysimeter at Gainesville, showed that a crop of turnips
reduced the volume of water lost by percolation from a 4-foot
profile of Norfolk loamy fine sand between December 29 and
March 27 by 4.3 inches or 46 percent. Evaporation from this
soil in fallow condition during the same period was 3.87 inches
or 29.4 percent of the rainfall. It was also found that leaching
did not begin under an actively growing millet crop until the
monthly accumulated rainfall had reached 7.4 inches, but from
then on the volume of percolate was approximately equal to
rainfall in excess of this amount.
The amount of leachable nitrogen which would be present in
the soil at a given time interval after fertilization would be
affected by the rate of change in solubility under the existing
condition. In this connection, the rate of nitrate formation in
the soil from a wide range of nitrogen carriers was shown by
Rubins and Bear (7) to be closely .related to their C-N ratio;
the higher the proportion of nitrogen, the more rapid the con-
version. Bell (3) presented data which indicated that the cumu-
lative reversion of the nitrogen of ammonium sulfate to the
nitrate form in Norfolk sand reached a maximum in approxi-
mately 3 months' time. Barnette, Jones and Hester (1) showed
Italic figures in parentheses refer to Literature Cited in the back of
this bulletin.







Use of Nitrate Nitrogen in the Production of Cabbage 7

that the cumulative leaching of nitrates from Norfolk fine sand,
following incorporation of chopped green velvet bean and crota-
laria plants, approached a maximum within 5 months. Dyal,
Smith and Allison (4), using Norfolk loamy fine sand, found
that green crotalaria and natal grass decomposed more rapidly
in soils at pH values between 5.94 and 7.05 than between 3.71
and 4.59.
Volk and Bell (10) reported data on the effect of soil pH on
the retention of ammonia against leaching, which indicated that
the retention of ammonia by highly acid soils low in exchange
capacity might be improved by maintaining a pH of approxi-
mately 6.5, but that there was neglible effect of pH on the re-
tention of ammonia by soils of relatively high exchange capacity
within the moderately acid range.

EXPERIMENTAL PROCEDURE
The field work was carried out on 3-row plots 22.5 feet in
length with rows spaced 40 inches apart. The rows were ridged
8 to 12 inches high. and the plants were spaced 9 inches apart.
The cabbage variety used in all tests was Early Copenhagen
Market. Fertilizers were applied in double bands 2-to 4 weeks
before the plants were set. Fertilizer used for side-dressing
was applied by hand along each side of the plant row. The plots
were irrigated when set to cabbage and as needed thereafter.
Pounds of marketable cabbage produced in each plot were re-
corded and total yield for each treatment was converted to tons
per acre.
The majority of the tests were on typical Bladen fine sandy
loam in which a sandy loam surface of from 6 to 12 inches deep
overlaid a moderately heavy clay. The clay was at a shallower
depth in part of 1 experimental block.
Soil samples were taken periodically by means of a stainless
steel open-side tube 11/8 inches in diameter. Each sample con-
sisted of a composite of 7 plugs to 6 inches in depth through
the fertilizer band zone. Nitrates were extracted from the
field-moist samples the following day and determined by the
method proposed by Harper (5). Sampling immediately after
side-dressing or after rains was avoided as far as possible.
The various fertilizer practices tested are given in Tables 1
to 6 under Experimental Results and Discussion. They consisted
of various sources and amounts of nitrogen, phosphorus and po-
tassium in the drill, followed in many instances by various side-














TABLE 1.-EFFECT OF VARIOUS NITRATE OF POTASH SIDE-DRESSINGS TO CABBAGE ON MAINTENANCE OF NITRATE NITROGEN
IN BLADEN FINE SANDY LOAM, 1941-42 SEASON.
Nitrate of Potash
Treatment Drill Application* Side-Dressing Nitrate Nitrogen in Soil Yield
Number Pounds 5-7-5 per Acre Pounds Nitrogen per Acre Pounds per Acre Cabbage,t
11/20/41 1/8/42 1 1/26/421 2/4/42 1 1/7/42 1/23/42 2/3/42 | 2/23/42 1 *Tons/A

1 1,500 None None None 22.2** 22.4 12.6 3.2 9.16
2 1,500 21 None None 22.2** 50.8** 34.0 12.2 10.19
3 1.500 21 21 None 22.2** 50.8** 66.0 37.4 10.85
4 1,500 21 21 21 22.2** 50.8** 63.0 43.6 11.06
5 2,000 None None None 40.4** 43.2 24.0 9.8 10.02
6 2,000 21 None None 40.4** 76.6** 34.2 26.6 11.26
7 2,000 21 21 None 40.4** 76.6** 77.2 45.4 11.44
8 2,000 21 21 21 40.4** 76.6** 65.8 59.8 11.69


Inches of rainfall from 11/20/41 to date .....................-. 5.52 5.52 5.98 7.93

Nitrogen units-212 sulfate ammonia, 1 castor pomace, 1 guano.
** Composite of all plots of similar treatment to date.
t Harvest started 2/9/42. Average of 10 replicates in randomized block design. Least significant difference of 0.87 tons at the 5% point.







Use of Nitrate Nitrogen in the Production of Cabbage 9

dressing practices. Plots were laid out in 8 x 8 Latin square
or in randomized block design. Only selected treatments were
sampled for nitrate nitrogen in 2 of the experimental blocks.
This was done because factors other than nitrogen were varied
in certain of the treatments.
Soil nitrate nitrogen data and yields of marketable cabbage
are the average of 8 replicates in all cases reported except in
Table 1, which was compiled from 10 replicates of a randomized
block design, and in part of Table 2, which was compiled from
2 replicates in a special test intended as a supplement to the
8 x 8 Latin square from which the remainder of the data in
Table 2 were obtained. The statistical analysis on yields was
always based on the full experiment, even though in some tests
only part of the treatments were sampled for soil nitrate nitro-
gen. Yields from unsampled treatments are not reported.
Pounds per acre nitrate nitrogen were obtained by converting
parts per million on the basis of 2,000,000 pounds of soil per
acre-6-inches. Analysis of variance of soil tests for nitrate
nitrogen between treatments was not made because the span
between high nitrate producing treatments and low nitrate pro-
ducing treatments was so great that fallacious significance
would have been obtained.
Three other soil tests-pH, organic matter and moisture
equivalent-were made when it was thought that they would
be of help in analyzing the responses of the crop to the various
treatments. The pH was determined with the glass electrode,
using'the precautions recommended by Volk and Bell (10).
Soil organic matter was determined by the method proposed by
Walkley (12) and soil moisture equivalent by the method of
Briggs and McLane (2).
Plant tissue tests for nitrate nitrogen were made by the
diphenylamine method of Thornton, Conner and Frazer .(8) for
the purpose of correlation with the soil test for nitrate. The
test was made on the severed midrib approximately 1/3 of the
distance out from the base toward the tip of a well developed
leaf.

EXPERIMENTAL RESULTS AND DISCUSSION
Table 1 consists of data obtained from treatments in which
from 1 to 3 nitrate of potash side-dressings were used in con-
junction with 2 levels of complete fertilizer in the drill. The
yield of cabbage from all treatments was generally low. The







Florida Agricultural Experiment Station


cabbage was planted in November and harvested before the
warm spring weather came. The 2,000-pound drill application
of 5-7-5 in which the nitrogen was derived from ammonium
sulfate, castor pomace and guano maintained a higher nitrate
nitrogen level in the soil throughout the sampling period than
did the 1,500-pound application of the same formula. The differ-
ence became less as the season progressed but this could be
partially accounted for by the uniformly larger yields from
the higher drill application.
The differences in soil nitrate nitrogen resulting from differ-
ent numbers of side-dressings are very marked. In every in-
stance 1 additional side-dressing was reflected by the soil nitrate
nitrogen level, even on the last sampling date, and the yields
reflected these differences, especially when the level dropped
below approximately 20 pounds of nitrate nitrogen per acre
at the start of the harvest. There is the possibility that potas-
sium may have been a factor, because it varied in proportion
to the nitrogen in the side-dressing, but McCubbin (6) stated
in his report on associated tests that there was no response to
side-dressings of muriate of potash without the nitrate. There-
fore nitrogen and not potassium was the dominant factor.
Data on the effect of various amounts and sources of nitrogen
in an equal number of side-dressings used in conjunction with
a 1,500-pound 5-7-5 drill application are presented in Table 2.
The first 4 treatments were part of an 8 x 8 Latin square, while
the last 3 are from a supplementary test not part of the Latin
square but on a similar soil in its immediate vicinity and on
the same time schedule of planting, fertilization and harvest.
It appears from Treatment 1 that a very heavy application of
urea had the ability to supply adequate nitrogen to the plant,
even though nitrate nitrogen did not appear in quantity in
keeping with the yield. This indicates either that the crop was
obtaining considerable nitrogen in other than nitrate form or
that the distribution of urea in the soil was such that the crop
could obtain sufficient of the nitrate from a relatively low con-
centration that was well distributed and maintained by the urea.
This is 1 of the few instances in which an adequate supply of
available nitrogen in the absence of a considerable excess of
the nitrate form was adequate for a high yield of cabbage. The
factors involved need further investigation. The lighter applica-
tion of urea in Treatment 5 did not give a response in keeping
with that of an equal quantity of nitrogen in the nitrate form













TABLE 2.-EFFECT OF VARIOUS SOURCES AND AMOUNTS OF NITROGEN IN SIDE-DRESSINGS ON MAINTENANCE OF NITRATE
NITROGEN IN BLADEN FINE SANDY LOAM PLANTED TO CABBAGE, 1941-42 SEASON.

Treatment *
Source and Total Pounds of Nitrogen per Acre Nitrate Nitrogen in Soil,
in Split Side-Dressings Pounds per Acre Yield
1/9/42, 2/4/42, 3/18/42 Cabbage,**
Nitrate Sulfate of Tons/A
No. of Soda Ammonia Cyanamide Urea 2/13/42 2/26/42 3/12/42

1 189 16.2 11.6 6.4 19.51
2 72 43.2 33.4 13.6 18.16
3 92 10.4 5.2 3.0 16.84
4 94.5 14.0 4.4 2.6 14.99
5 72 13.2 4.6 2.4 15.50t
6 72 11.8 5.0 2.4 15.00t
7 72 22.6 5.8 1.4 13.32t


Inches of rainfall from 12/12/41 to date ........................... 3.78 7.47 10.22

1.500 lbs. 5-7-5 in drill on 12/12/41. Nitrogen units-2%2 sulfate of ammonia, 1 castor pomace. 1% guano.
** Harvest started 3/16/42. Least significant difference 1.71 tons at the 5% point for Treatments 1 to 4, inclusive.
t Two replicates only, without statistical analysis. All others, 8 replicates from 8 x 8 Latin square.







Florida Agricultural Experiment Station


in Treatment 2. With the exception of the first treatment, the
data on nitrate nitrogen substantiates those of Table 1. The
generally higher yields are in all probability a reflection of the
additional 35 days of spring weather which the latter trials
had in their favor before the start of harvest.
Data obtained from 6 treatments taken from an 8 x 8 Latin
square in which various sources and amounts of nitrogen were
used in the drill with no supplementary side-dressing are pre-
sented in Table 3. There is little evidence here of the superior-
ity of nitrate nitrogen in maintaining nitrates in the soil where
equal low rates of nitrogen were applied. The crop apparently
used the limited amount of nitrate nitrogen early in its growth
period. In the case of the higher rates of nitrate nitrogen in
the drill, the persistence of nitrate in the soil is very marked
and the yield response very high. The correlation of yield with
the level of nitrate nitrogen at the approach of harvest is es-
sentially in agreement with the data previously discussed.

TABLE 3.-SOIL NITRATE NITROGEN MAINTAINED BY VARIOUS FERTILIZER
TREATMENTS IN THE DRILL WITH CABBAGE ON BLADEN FINE SANDY
LOAM, 1941-42 SEASON.


2,000-Pound Drill
Application Formula
and Nitrogen Source


I
Nitrate Nitrogen in Soil, I
Pounds per Acre I


Yield
Cabbagee*


No. 12/4/41 2/13/42 1 2/26/42 3/12/42 Tons/A
15-7-5
1 nitrate of soda ........... 179.6 75.0 59.0 16.66
10-7-5
2 nitrate of soda ............ 102.0 33.4 17.6 16.21
5-7-5
3 nitrate of soda ........... 20.4 4.0 1.6 12.17
5-7-5
4 2% nitrate of soda ....-. 18.8 5.4 3.4 12.09
I 2/2 sulfate of ammonia
5-7-5
21/ sulfate of ammonia
5 11/ guano --..... ........... 16.6 4.8 2.2 11.70
1 castor pomace ..........
5-7-5
6 sulfate of ammonia .... 10.8 2.6 1.4 11.66
Inches of rainfall from 12/4/41
to date ...................................... 5.01 8.70 11.45 _
Harvest started 3/9/42. Average of 8 replicates of 8 x 8 Latin square. Least sig-
nificant difference 0.93 tons at 5% point.

Table 4 contains data obtained from a second test of various
sources and amounts of nitrogen in the drill, carried on the
following year after the data in Table 3 were obtained. The
soil area was quite highly variable in texture and organic mat-


Treat-
ment







Use of Nitrate Nitrogen in the Production of Cabbage 13

ter content, and the rainfall such that the effect of these vari-
ations on the crop were emphasized. The soil nitrate nitrogen
level from all treatments was exceptionally high as compared to
previous tests. There was some evidence of the same signifi-
cance of nitrate nitrogen level in the soil as previously noted,
but it was obvious from a study of individual plot yields that
the lighter the texture of the soil the higher the yield in this
set of plots. The soil condition bringing about this effect will
be discussed after completing the presentation of data from the
several tests.

TABLE 4.-SOIL NITRATE NITROGEN MAINTAINED BY VARIOUS FERTILIZER
TREATMENTS IN THE DRILL WITH CABBAGE ON BLADEN FINE SANDY
LOAM, 1942-43 SEASON.

2,000-Pound Drill Nitrate Nitrogen in Soil,
Application Pounds per Acre Yield
d E Formula and Cabbage,*
B 0 Nitrogen Source Tons/A
E, 12/8/42 1/5/43 1/25/43 2/10/43 3/1/43 3/23/43_

5-7-5
1 guano
1 1 castor pomace 53.0 84.2 27.2 18.0 7.8 11.9
21/2 sulfate of
ammonia
5-7-5
2 21/2 sulfate of
ammonia 72.2 78.8 25.8 19.6 10.2 13.9
2% nitrate of
soda
5-7-5
3 nitrate of soda 58.6 91.8 31.0 49.8 28.6 13.8
5-7-5
4 sulfate of am-. 29.8 35.6 12.2 10.4 5.0 12.5
monia
10-7-5
5 nitrate of soda 170.0 168.0 141.4 132.4 91.6 13.6
5-14-5
6 nitrate of soda 107.0 154.2 48.8 25.0 12.2 14.1
5-7-10
7 nitrate of soda 173.4 121.2 54.8 36.8 25.6 14.3
10-7-5
8 nitrate of potash 205.8 195.2 177.6 115.6 79.8 14.4

Inches of rainfall from
12/8/42 to date ...... 3.67 4.31 5.52 5.91 8.701_


Harvest started 3/10/43. Average of 8 replicates of
nificant difference of 1.0 ton at the 5% point.


8 x 8 Latin square. Least sig-







Florida Agricultural Experiment Station


The effect of various natural organic sources of nitrogen used
as side-dressing materials on the level of nitrate nitrogen in
the soil as compared with that of nitrate of soda are presented
in Table 5. The yields are relatively low with all treatments,
indicating that climatic factors were probably limiting. Except
for the fact that the highest yield occurs with the highest level
of nitrate nitrogen in the soil at the beginning of harvest, there
is little significance in the data. It appears that the organic
sources of nitrogen are unable to maintain a high level of nitrate
nitrogen in the soil when applied as side-dressing.

TABLE 5.-EFFECT OF SOURCE OF NITROGEN SIDE-DRESSING TO CABBAGE ON
THE SOIL NITRATE NITROGEN LEVEL IN BLADEN FIN, SANDY LOAM,
1942-43 SEASON.

Treat- Nitrate Nitrogen in Soil, Yield
ment Side-Dressing* Pounds per Acre Cabbage,**
No. 2/23/4313/15/431 4/5/43 14/22/431 Tons/A

1 nitrate of soda ...... 55.4 29.6 12.4 6.4 13.9
2 ground dried blood 34.2 7.8 2.4 3.0 12.3
3 steamed bone meal 30.4 8.6 3.2 4.0 13.1
4 peanut meal ............ 36.4 9.4 2.6 3.6 13.3
5 cator pomace .......... 42.6 11.0 3.0 2.2 13.2
6 high grade tankage 59.6 22.4 8.0 4.8 12.8
7 milorganite ............ 35.4 8.6 4.4 3.0 12.8
8 cottonseed meal ...... 42.8 11.0 3.0 4.2 13.0

Inches of rainfall from
12/26/42 to date .................. 3.56 6.09 7.41 8.62
All received 2,000 pounds of 5-7-5 in the drill on approximately 12/26/42; side-
dressings of 24 pounds nitrogen per application on 2/9/43. 3/9/43 and 3/29/43.
Harvest started 3/23/43. Average of 8 replicates of 8 x 8 Latin square. Least sig-
nificant difference 0.9 ton at the 5% point.

Table 6 presents data from treatments selected on the basis
of previous tests. The treatments consisted of drill applications,
and combinations of various drill and side-dressing practices.
The significance of the nitrate nitrogen level at the time of be-
ginning harvest again is in general agreement with previous
data. There is evidence that a response to the nitrate nitrogen
level up to approximately 20 pounds per acre exists. Here again
it is obvious that heavy applications of nitrate nitrogen in the
drill can maintain a high level of nitrate nitrogen in the soil
throughout the growing period and produce yields equal to those
obtained with a split application of nitrogen. A general evalu-
ation of different types of source materials and methods of use
with respect to their ability to maintain a desirable level of








Use of Nitrate Nitrogen in the Production of Cabbage 15

nitrate nitrogen in the soil is discussed later in connection with
Figure 1.

TABLE 6.-EFFECT OF VARIOUS FERTILIZER TREATMENTS WITH CABBAGE
ON THE NITRATE NITROGEN LEVEL IN BLADEN FINE SANDY LOAM, 1944-45
SEASON.
Yield
Treatment PPM Nitrate Nitrogen Cab- Soil pH
Pounds per Acre in Soil bage,** on
and Nitrogen Source 1/29/4512/28/4513/13/451 Tons/A 2/28/45


1 2,000 lbs. com. 5-7-5 ..........

2 2,000 lbs. 5-7-5. N from
nitrate of soda ................

3 800 lbs. com. 5-7-5. 600
lbs. same on 12/15/44
and 12/28/44 ................

4 2,000 Ibs. com. 5-7-5 plus
nitrate of soda, to make
up to 10-7-5 .......- ........

5 1,500 lbs. com. 5-7-5. 24
lbs. N from nitrate of
potash on 12/15/44,
12/28/44, 3/2/45 ............

6 2,000 lbs. com. 5-7-5. 24
lbs. N from nitrate of
potash on 12/15/44
12/28/44, 3/2/45 ........

7 2,000 lbs. 10-7-5. N from
nitrate of soda ................

8 2,000 lbs. 10-7-5. N from
nitrate of soda, 24 lbs.
N from nitrate of potash
on 3/2/45 ......-....-...--.--

9 1,500 lbs. 10-7-5. N from
nitrate of soda ..............

10 1,500 lbs. 10-7-5. N from
nitrate of soda, 24 lbs.
N from nitrate of potash
on 3/2/45 ........................

11 2,000 Ibs. 10-9-7. All
nitrate nitrogen ............


45.2



26.6



38.4

78.4



84.8

71.0



65.4

87.0


3.7

16.2


3.4


31.2



12.4



17.0


48.2



74.6

48.2



28.0

48.8


Trace

3.2


Trace


16.8


11.0



17.0


36.0



32.8

31.2



20.6

35.2


13.81

16.71


14.19


16.96



16.35



16.46


17.48



17.59

18.47



17.78


18.62 5.21


Inches of rainfall 11/8/44
to date ............................... 4.74 5.17 5.19
The first amount listed under each treatment is a drill application on 11/8/44, while
remaining (dated) applications are side dressings. "Com." refers to a commercial 5-7-5
containing 2.75 units of N from sulfate of ammonia, 1.13 units from urea, and 1.12 from
insoluble organic.
** Harvest started 2/12/45. Average of 8 replicates in randomized block design. Least
significant difference 1.79 tons at the 5% point.








Florida Agricultural Experiment Station


As previously stated, soil pH is of interest in nitrogen economy
because it can become a factor in the leaching of nitrogen.
Table 6 illustrates the effects of various sources of nitrogen
on soil pH. The soil pH was determined 82 days after treat-
ment. There is an average difference with treatments in which
a nitrate was the source of nitrogen and those in which non-
nitrate forms of nitrogen were used of approximately 0.7 pH unit.
This is undoubtedly divided between the alkaline effect of the
residual sodium ion and the acidifying effect of the ammonium
sulfate and certain of the organcis. There is little doubt that
continued use of a given treatment could so change the soil pH
that efficiency of the treatment would be affected unless cor-
rective measures were employed.


0
o A O

O a o
/ 0




a 0


x ,




El FROM TABLE I





POUNDS NITEATE NITROGEN PER. AC XE' IM SOIL

Fig. 1.-The correlation of nitrate nitrogen in the soil at the start of
harvest with the yield of cabbage. The percent of maximum yield is the
yield of any given treatment figured percentagely against the best yielding
treatment in any given set of comparative tests, in each of which there
were 8 or more different treatments. The critical point at approximately
15 pounds of nitrate nitrogen per acre correlates with an average yield of
92 percent of maximum and a range of 83 to 100percent of maximum yield.


An attempt to obtain a general evaluation of the data from
the previous tables was made by reporting yields as percent
of the maximum yield for any given test and then plotting the
resulting data against the level of soil nitrate nitrogen found







Use of Nitrate Nitrogen in the Production of Cabbage 17

or calculated to be present at the time of start of harvest. The
first was done by taking the maximum yield for a given test as
100 percent. Each remaining yield of that particular test was
then reported on the basis of the percent of this maximum.
This method of handling the data had the effect of partially
eliminating climatic factors which produced generally high or
low yields. Each test contained certain treatments which could
have been expected to produce a relatively high yield under
favorable conditions. There is a fallacy involved, because the
same treatment was not always used for the 100 percent yield
reference, but the practice does have the advantage of simplify-
ing data without the bias that individual evaluation of tests
followed by a general conclusion would introduce. The nitrate
nitrogen value found at the beginning of harvest was chosen
because it appeared to be as close an estimate of the minimum
critical nitrate level as would be practical to obtain from the
type of data available.
The data recalculated by the above-described method are
plotted in Figure 1. The source of data can be determined by
the type of point used. The mean curve appearing in the figure
is a running mean of points normal to a medium curve deter-
mined from points median for experimental points falling in
intervals on each axis in succession.
Examination of the mean curve shows that there is a rapid
increase in yield with increase in nitrate nitrogen in the soil
up to approximately 15 pounds of nitrate nitrogen per acre.
The yield response to added increments of nitrate nitrogen above
this point drops off. The average yield for treatments maintain-
ing approximately 15 pounds of nitrate nitrogen per acre was
approximately 92 percent of maximum yields for the various
tests. The extreme range was from 83 to 100 percent of maxi-
mum. Fifteen pounds appear to be a logical minimum if nitrate
nitrogen in the soil is to be used as a criterion of nitrogen supply
to produce a high yield. When the nitrate nitrogen drops below
this level, a side-dressing of nitrate could be used to replenish
the supply. During years when a low price for the crop is ex-
pected, the nitrate nitrogen level might be allowed to drop as
low as 8 to 10 pounds per acre so as to effect a saving in labor
and materials..
The plant tissue test was found to change from weak to strong
when the soil nitrate nitrogen was at approximately 3.5 pounds
per acre. Up to this value there was a dominance of low tests







Florida Agricultural Experiment Station


with 71 percent testing weak. Above this point there was domi-
nance of high tests with 95 percent of them testing strong. It
is obvious that the tissue test would be of little value in control
of the side-dressing practice for a good yield of cabbage. When
the nitrate nitrogen gets so low that the test is negative, nitro-
gen starvation is so obvious that the test is unnecessary in
analysis of the condition.
Refinements in the use of nitrate nitrogen in the soil as a
criterion of supply to the plant can be made if the source of
nitrogen and the season are taken into account. High nitrate
nitrogen is more necessary in cold weather when availability
of other forms of nitrogen is low. The data show that other
.forms of nitrogen, in sufficient quantity, may supply much higher
levels of available nitrogen to the plant during warm weather
than is indicated by the nitrate nitrogen in the soil (Table 2,
Treatment 1). This is probably the result of rapid utilization
of the nitrogen as fast as converted, without allowing the buildup
of any significant excess of the nitrate form. It is also recog-
nized that the ability of the crop to utilize nitrogen in a form
other than nitrate may vary with changes in soil temperature.
and that plants of different ages vary in their ability to utilize
the ammonia form efficiently. Plants have the ability to store
nitrate nitrogen, probably in the form of asparagine and similar
compounds, for future use in the synthesis of proteins; while
ammonia nitrogen apparently cannot be stored but is used im-
mediately in the synthesis of an end product. Such factors
complicate the use of nitrate nitrogen in the soil as an indicator
of the supply to the plant.
As previously implied, leaching losses of nitrogen and utiliz-
ation by plants are markedly affected by soil characteristics.
The data in Table 4 are an excellent example of this. The yield
data in Table 4 were first equated to a common average by
fertilizer treatments so as to eliminate the effect of treatment
on yield as far as possible. The recalculated yield for each in-
dividual plot was then plotted against soil moisture equivalent.
Soil moisture equivalent was used as a criterion of soil hetero-
geneity because it has been found that it is an excellent meas-
ure of a condition reflecting texture and organic matter changes
and the general differences in moisture relationships. The data
obtained are presented in Figure 2.
The soil nitrate nitrogen level of the individual plots 44 days
before harvest was equated to a common average of treatments







Use of Nitrate Nitrogen in the Production of Cabbage 19

in a similar manner and also appears plotted against soil moist-
ure equivalent in Figure 2. This time of sampling was selected
for presentation because it represented the greatest variation
in nitrates resulting from soil variation. The mean curves were
arrived at in the same manner as described for Figure 1.


0 14-
SOIL MOISTURE E9uIVALENT PLECENT


Fig. 2.-The influence of soil variation as measured by soil moisture
equivalent on yield of cabbage and on the retention and maintenance of
nitrate nitrogen in the soil following the addition of nitrogenous fertilizers.
Data were obtained by equating treatments of an 8 x 8 Latin square to a
common average. Curves are running means of points normal to a median
curve obtained from median points of intervals on each axis in succession.

There is a definite inverse correlation of yield with soil moist-
ure equivalent and a positive correlation of nitrate nitrogen in
the soil with moisture equivalent. The average yield at 18
percent moisture equivalent was approximately 11.5 tons per
acre, while the yield at 7 percent moisture equivalent was ap-
proximately 17 tons per acre, or 48 percent more. On the other
hand, the nitrate nitrogen was approximately 238 pounds per
acre at the higher moisture equivalent where the yield was
lowest, and approximately 20 pounds per acre at the low moist-







Florida Agricultural Experiment Station


ure equivalent where the yield was highest. The low nitrate
nitrogen in this instance is probably the result of both leaching
loss from the lighter textured soil and greater utilization by
the heavier crop. The average response of the crop obviously
was not to nitrate nitrogen but to soil texture, and appears to
be related to water efficiency. The runoff from the heaviest
soil was relatively high as compared with that of the more sandy
soil. The clay subsoil in the Bladen soils prevents excessive
gravitational loss of water, and in this instance made the lighter
textured soil the most efficient in the use of water.

I I


4



2*
*0 -














Fig. .-The relation of soil moisture equivalent to percent soil organic
matter in 258 samples of Bladen fine sandy loam surface soil. Experi-
mental points represent the averages of original values occurring within
0.1 percent intervals on the organic matter axis.

It is of interest to note that despite the inverse relationship
of nitrates to yield, expressed in Figure 2, the 2 treatments
given in Table 4, which produced low nitrates, showed a sig-
nificantly lower yield than those producing high nitrates. The
type of randomization provided by the Latin square was highly
efficient in showing the significance of nitrates in the presence
of such marked soil variation effect.







Use of Nitrate Nitrogen in the Production of Cabbage 21

The significance of soil moisture equivalent as a measure of
soil variation is brought out by. its correlation with organic
matter in the soils used in the preceding tests. Figure 3 shows
this relationship as a mean curve of the 258 samples in which
percent organic matter is plotted against moisture equivalent.
The points used in the figure are the mean of all moisture equiva-
lent values occurring within 0.1 percent intervals on the organic
matter axis. The ratio of percent organic matter to percent
moisture equivalent is approximately 1:4.5.
The foregoing analysis of the data in Table 4 shows how
necessary it is that a given soil sample be limited to a uniform
soil area so that compositing of samples does not invalidate the
data obtained.
SUMMARY
The nitrate nitrogen in Bladen fine sandy loam was determined
periodically following fertilization of cabbage with various com-
binations of drill applications with and without side-dressings.
A general positive correlation between nitrate nitrogen in the
soil just prior to harvest and the yield of marketable cabbage
was found. The critical point in nitrate content of the soil at
this time was approximately 15 pounds of nitrate nitrogen per
acre. Above this value the response to larger amounts of nitrate
dropped rapidly. An average yield expectancy of 92 percent
of maximum and a range of 83 to 100 percent of maximum was
found for treatments supplying this amount of nitrogen at the
beginning of harvest. The use of nitrate side-dressings is indi-
cated when the soil nitrate nitrogen drops below 15 pounds of
nitrate nitrogen per acre, if a high yield is desired.
Nitrate nitrogen as the source of nitrogen in -the drill appli-
cation will maintain the highest level of nitrates in Bladen fine
sandy loam during the growing season under average conditions.
Other sources of nitrogen in the drill will not maintain as high
a nitrate level during the growing season for cabbage and should
be supplemented with nitrate nitrogen as side-dressing. Soil
characteristics play such a major part in the retention of nitrate
nitrogen in Bladen soils that each soil sample must be limited
to a relatively uniform area in order to obtain dependable results
from the.analysis. It was found that soil texture as measured
by moisture equivalent was inversely correlated with yield dur-
ing a season of unfavorable rainfall, but that nitrate nitrogen
was positively correlated with moisture equivalent when treat-
ment differences were eliminated. However, there was a sig-








Florida Agricultural Experiment Station


nificant response to nitrate nitrogen as shown by the statistical
analysis of yields on plots laid. out on the Latin square.
The diphenylamine tissue test for nitrate nitrogen had too
low a critical point to be of value in determining side-dressing
practices.

LITERATURE CITED

1. BARNETTE, R. M., H. W.'JONES and J. B. HESTER. Lysimeter studies
with the decomposition of summer cover crops. Fla. Agr. Exp. Sta.
Bul. 327: 1-44. 1938.
2. BRIGGS, L. J., and J. W. McLANE. Moisture equivalent determinations
and their application. Proc. Amer. Soc. Agron. 2: 138-147. 1910.
3. BELL, C. E. Rate of decomposition of organic matter in Norfolk sand
as measured by the formation of carbon dioxide and nitrates. Jour.
Agr. Res. 50: 717-730. 1935.
4. DYAL, R. S., F. B. SMITH and R. V. ALLISON. The decomposition of
organic matter in soils at different initial pH. Jour. Amer. Soc.
Agron. 31: 841-850. 1939.
5. HARPER, H. J. The accurate determination of nitrates in soils. Jour.
Ind. Eng. Chem. 16: 180-183. 1924.
6. McCUBBIN, E. N. Importance of fertilizer nitrogen for cabbage pro-
duction on sandy soils of northeast Florida. Fla. State Hort.
Soc. Proc. 58: 238-242. 1945.
7. RUBINS, E. J., and FIRMAN E. BEAR. Carbon-nitrogen ratios in organic
fertilizer materials in relations to the availability of their nitrogen.
Soil Sci. 54: 411-423. 1942.
8. THORNTON, S. F., S. D. CONNER and R. R. FRAZER. The use of rapid
chemical tests on soils and plants as aids in determining fertilizer
needs. Pinrdue Univ. Agr. Exp. Sta. Circ. 204 (Revised): 1-16.
1939.
9. VOLK, G. M. The significance of the soil nitrate test for cabbage.
Fla. State Hort. Soc. Proc. 57: 232-236. 1944.
10. VOLK, G. M., and C. E. BELL. Soil reaction (pH). Some critical
factors in its determination, control and significance. Fla. Agr.
Exp. Sta. Bul. 400: 1-43. 1944.
11. VOLK, G. M., and C. E. BELL. Some major factors in the leaching of
calcium, potassium, sulfur and nitrogen from sandy soils. Fla.
Agr. Exp. Sta. Bul. 416: 1-23. 1945.

12. WALKLEY, ALLEN. An examination of methods for determining organic
carbon and nitrogen in soils. Jour. Agr. Sci. 25: 598-609. 1935.




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