• TABLE OF CONTENTS
HIDE
 Copyright
 Front Cover
 Table of Contents
 Introduction
 Experimental
 Discussion
 Recommendations, acknowledgments,...






Group Title: Bulletin - Agricultural Experiment Station, University of Florida - 577
Title: Magnesium and lime are needed in the Suwanee Valley area
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027520/00001
 Material Information
Title: Magnesium and lime are needed in the Suwanee Valley area
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 13 p. : ill., map ; 23 cm.
Language: English
Creator: Blue, William G
Eno, Charles F
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1956
 Subjects
Subject: Plants -- Effect of magnesium on -- Florida -- Suwanee River Valley   ( lcsh )
Soils -- Magnesium content -- Florida -- Suwanee River Valley   ( lcsh )
Liming of soils -- Florida -- Suwanee River Valley   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 13.
Statement of Responsibility: William G. Blue and Charles F. Eno.
General Note: Cover title.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00027520
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 - 000926783
oclc - 18287269
notis - AEN7483

Table of Contents
    Copyright
        Copyright
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
        Page 4
    Experimental
        Page 5
        Plant response to magnesium
            Page 5
            Pot experiments
                Page 5
                Page 6
            Field experiments
                Page 7
                Page 8
        Soil analysis
            Page 9
            Magnesium, calcium and pH studies
                Page 9
            Nitrification rates
                Page 9
                Page 10
    Discussion
        Page 11
        Page 12
    Recommendations, acknowledgments, and literature cited
        Page 13
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






August 1956


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
J. R. BECKENBACH, Director
GAINESVILLE, FLORIDA












Magnesium and Lime Are Needed in the

Suwannee Valley Area



WILLIAM G. BLUE AND CHARLES F. ENO
Associate Biochemist and Associate Soil Microbiologist















Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


Bulletin 577























CONTENTS
Page

INTRODUCTION ................---..................------------.. 3

EXPERIMENTAL .........-..-- ....................... -------- ------------------- 5

Plant Response to Magnesium ......-.......-....... ------------------- 5

Pot Experiments ..........-..... -------........-------- 5

Field Experiments ...............--------..... ----------------- 7

Soil Analysis ................. -----....... -------------- -------- 9

Magnesium, Calcium and pH Studies ......................----------........ 9

Nitrification Rates .....--...-.........--.. -------------------- 9

DISCUSSION -.~.. --------..-----------........................ 11

RECOMMENDATIONS ...................-.. -------------- ------------- 13

ACKNOWLEDGMENTS .........--..... --------......---- --------- ------- 13

LITERATURE CITED .....--.............-.... ----------------------------------. 13








Magnesium and Lime Are Needed in the

Suwannee Valley Area

WILLIAM G. BLUE AND CHARLES F. ENO

INTRODUCTION
The magnesium content of many of the light, well-drained
Coastal Plain soils is very low, but at present magnesium is ap-
plied only for heavily fertilized crops such as citrus, tobacco and
vegetables. It is usually applied as a soluble salt in commercial
fertilizers or as dolomitic lime.
While the magnesium content of this group of soils is usually,
low, the major plant foods-nitrogen, phosphorus and potas-
sium-generally are lower than magnesium. For most forage
and field crops these major plant foods are not applied in
sufficiently large quantities to cause the plants to outgrow the
limited supply of magnesium in the soil.
Magnesium deficiency also has been reduced by its uninten-
tional use as an impurity in low-grade fertilizer salts and in
dolomitic lime, which is frequently used for fertilizer filler.
However, the development of purer fertilizer materials, the use
of higher analysis fertilizer and the use of larger quantities
of the major plant foods, without doubt, will result in more
widespread deficiencies of this element.
Because magnesium and some minor element deficiencies
have occurred frequently with heavy fertilization in the Coastal
Plain area, field and greenhouse experiments were conducted
to evaluate the magnesium status of soils in the Suwannee
Valley area.
In this report concentrations of magnesium and other nutri-
ents are shown for several forage plants grown on Jonesville
and Klej fine sandy soils in the Suwannee Villey area of Florida.
The magnesium content of these and a number of other soils
is shown. The relationship between ammoniacal nitrogen and
magnesium deficiency and reduced plant concentrations of mag-
nesium is pointed out. The relatively low concentration of mag-
nesium in these soils and in the forage crops produced, their low
fertility status, their low capacity for nitrification and the place
of dolomitic lime for the purpose of supplying magnesium and
improving the fertility status of these soils are discussed.

































































Fig. 1.-Magnesium, deficiency symptoms for oats, top;
pearlmillet, center; and sweetclover.







Magnesium and Lime Needed in Suwannee Valley


EXPERIMENTAL

PLANT RESPONSE TO MAGNESIUM
A field experiment on Jonesville fine sand comparing a com-
bination treatment of magnesium and some minor elements with
a treatment having none of these elements showed that higher
yields for oats, sweetclover and lupine were obtained during the
first year from the magnesium-minor element treatment. A
nutrient deficiency was suspected and pot experiments with this
soil were initiated to determine which element was responsible
for the yield response. The pot experiments proceeded simul-
taneously with further field tests.
Pot Experiments.-Oats and sweetclover were planted in sep-
arate experiments. Pearlmillet followed each of these crops.
Magnesium, copper, manganese, zinc, molybdenum and boron,
which were included in the original field experiments, were the
elements used as variables. Nitrogen, potassium, phosphorus
and sulfur were supplied in quantities such that they did not
limit growth. High calcium lime was applied at a rate equivalent
to one ton per acre. Magnesium was added at the beginning
of the experiment at a rate equivalent to 100 pounds of mag-
nesium sulfate per acre (9.9 pounds of magnesium).
Magnesium was the only element which proved to be deficient.
Magnesium deficiency symptoms of oats, pearlmillet and sweet-
clover are shown in Figure 1. The deficiency symptom for
oats and pearlmillet is a chlorosis of the leaf (yellowing) with
blotches of chlorophyll (green); the chlorotic areas eventually
die. For sweetclover the deficiency consists of a marginal and
interveinal chlorosis.
Data for three cuttings of oats are shown in Table 1. All
elements except magnesium appear to have been present in
sufficient quantity. The magnesium content of plants from all
treatments was very low. There were no differences in yields
from the first cutting. Differences in magnesium concentra-
tions were small. Following the third cutting a general de-
ficiency of this element was noted in all treatments. Additional
magnesium (200 pounds magnesium sulfate per acre) was ap-
plied. This resulted in increased yields and increased magnes-
ium in the plants. Yields for the fourth and fifth clippings were
increased by 22 and 33 percent, respectively. The magnesium
content of the plants was doubled by the magnesium treatment.
Sweetclover yields and the magnesium content, shown in
Table 2, followed trends similar to those for oats. For the second







Magnesium and Lime Needed in Suwannee Valley


EXPERIMENTAL

PLANT RESPONSE TO MAGNESIUM
A field experiment on Jonesville fine sand comparing a com-
bination treatment of magnesium and some minor elements with
a treatment having none of these elements showed that higher
yields for oats, sweetclover and lupine were obtained during the
first year from the magnesium-minor element treatment. A
nutrient deficiency was suspected and pot experiments with this
soil were initiated to determine which element was responsible
for the yield response. The pot experiments proceeded simul-
taneously with further field tests.
Pot Experiments.-Oats and sweetclover were planted in sep-
arate experiments. Pearlmillet followed each of these crops.
Magnesium, copper, manganese, zinc, molybdenum and boron,
which were included in the original field experiments, were the
elements used as variables. Nitrogen, potassium, phosphorus
and sulfur were supplied in quantities such that they did not
limit growth. High calcium lime was applied at a rate equivalent
to one ton per acre. Magnesium was added at the beginning
of the experiment at a rate equivalent to 100 pounds of mag-
nesium sulfate per acre (9.9 pounds of magnesium).
Magnesium was the only element which proved to be deficient.
Magnesium deficiency symptoms of oats, pearlmillet and sweet-
clover are shown in Figure 1. The deficiency symptom for
oats and pearlmillet is a chlorosis of the leaf (yellowing) with
blotches of chlorophyll (green); the chlorotic areas eventually
die. For sweetclover the deficiency consists of a marginal and
interveinal chlorosis.
Data for three cuttings of oats are shown in Table 1. All
elements except magnesium appear to have been present in
sufficient quantity. The magnesium content of plants from all
treatments was very low. There were no differences in yields
from the first cutting. Differences in magnesium concentra-
tions were small. Following the third cutting a general de-
ficiency of this element was noted in all treatments. Additional
magnesium (200 pounds magnesium sulfate per acre) was ap-
plied. This resulted in increased yields and increased magnes-
ium in the plants. Yields for the fourth and fifth clippings were
increased by 22 and 33 percent, respectively. The magnesium
content of the plants was doubled by the magnesium treatment.
Sweetclover yields and the magnesium content, shown in
Table 2, followed trends similar to those for oats. For the second







Magnesium and Lime Needed in Suwannee Valley


EXPERIMENTAL

PLANT RESPONSE TO MAGNESIUM
A field experiment on Jonesville fine sand comparing a com-
bination treatment of magnesium and some minor elements with
a treatment having none of these elements showed that higher
yields for oats, sweetclover and lupine were obtained during the
first year from the magnesium-minor element treatment. A
nutrient deficiency was suspected and pot experiments with this
soil were initiated to determine which element was responsible
for the yield response. The pot experiments proceeded simul-
taneously with further field tests.
Pot Experiments.-Oats and sweetclover were planted in sep-
arate experiments. Pearlmillet followed each of these crops.
Magnesium, copper, manganese, zinc, molybdenum and boron,
which were included in the original field experiments, were the
elements used as variables. Nitrogen, potassium, phosphorus
and sulfur were supplied in quantities such that they did not
limit growth. High calcium lime was applied at a rate equivalent
to one ton per acre. Magnesium was added at the beginning
of the experiment at a rate equivalent to 100 pounds of mag-
nesium sulfate per acre (9.9 pounds of magnesium).
Magnesium was the only element which proved to be deficient.
Magnesium deficiency symptoms of oats, pearlmillet and sweet-
clover are shown in Figure 1. The deficiency symptom for
oats and pearlmillet is a chlorosis of the leaf (yellowing) with
blotches of chlorophyll (green); the chlorotic areas eventually
die. For sweetclover the deficiency consists of a marginal and
interveinal chlorosis.
Data for three cuttings of oats are shown in Table 1. All
elements except magnesium appear to have been present in
sufficient quantity. The magnesium content of plants from all
treatments was very low. There were no differences in yields
from the first cutting. Differences in magnesium concentra-
tions were small. Following the third cutting a general de-
ficiency of this element was noted in all treatments. Additional
magnesium (200 pounds magnesium sulfate per acre) was ap-
plied. This resulted in increased yields and increased magnes-
ium in the plants. Yields for the fourth and fifth clippings were
increased by 22 and 33 percent, respectively. The magnesium
content of the plants was doubled by the magnesium treatment.
Sweetclover yields and the magnesium content, shown in
Table 2, followed trends similar to those for oats. For the second







Florida Agricultural Experiment Stations


TABLE 1.-YIELDS AND PERCENTAGES OF ELEMENTS IN OVEN-DRY OATS
FROM THE POT EXPERIMENT.


Treatment Yield I N i K I Ca
Sgms./pot I % % I %
(First cutting, 12/22/53)

No magnesium ...... 5.8 4.3 4.2 0.67
Magnesium 5.9 4.3 4.2 0.66
(Fourth cutting, 2/22/54)

No magnesium .... 5.7 3.4 4.3 0.97
Magnesium ............... 6.9 3.4 4.0 0.79
(Fifth cutting, 3/10/54)

No magnesium ....... 7.0 2.7 3.0 0.83
Magnesium .............. 9.4 2.7 2.7 0.62


Mg P
% I%


0.086
0.092


0.34
0.34


0.061 0.29
0.120 0.24


0.077 0.24
0.161 0.23


TABLE 2.-YIELDS AND PERCENTAGES OF ELEMENTS IN OVEN-DRY
SWEETCLOVER FROM THE POT EXPERIMENT.

Treatment Yield IN I K I Ca I Mg I P
Sgms./pot % % i % I % %
(First cutting, 1/26/54)

No magnesium .......... 4.4 3.9 2.9 1.7 | 0.247 0.35
Magnesium ............. 4.3 3.8 2.7 1.8 0.244 | 0.35
(Second cutting, 3/10/54)

No magnesium ......... 11.4 2.9 2.4 1.1 0.101 0.31
Magnesium ................ 13.6 2.5 1.7 1.3 0.155 0.21


TABLE 3.-YIELDS AND PERCENTAGES OF ELEMENTS IN OVEN-DRY
PEARLMILLETT FROM THE POT EXPERIMENT.
(Harvested 5/15/54)

Treatment Yield 1 N K Ca Mg I P
Sgms./pot % I% % % \ %
Millett following oats

No magnesium ...-.. 10.1 2.9 3.9 0.55 0.052 0.22
Magnesium ................ 14.5 1.5 2.9 0.44 0.078 0.16
Millet following sweetclover
I T IT
No magnesium .......... 15.1 1.5 3.1 0.50 0.059 | 0.21
Magnesium ................ 15.8 1.5 2.8 0.38 | 0.099 0.24







Magnesium and Lime Needed in Suwannee Valley


cutting the average yield was 19 percent larger where mag-
nesium was. applied than where none was applied. The mag-
nesium content of plants was lower at the second cutting for
both treatments than at the first. This was partially due to
the clover being more mature. However, the magnesium con-
tent of clover plants where this element was applied was 50 per-
cent higher than where none was applied.
Data for pearlmillet following both oats and sweetclover are
shown in Table 3. Pearlmillet following oats responded to mag-
nesium more than when it followed sweetclover. The magne-
sium content of the pearlmillet following oats and sweetclover
was higher where magnesium was applied.
Field Experiments.-In the magnesium-minor element experi-
ment, magnesium was applied at the rate of 200- pounds of
magnesium sulfate per acre (19.8 pounds of magnesium) in the
fall of 1951 and again in the fall of 1952. High calcium lime
was applied at one ton per acre at the beginning of the experi-
ment,'

TABLE 4.-YIELDS AND PERCENTAGES OF ELEMENTS IN PEARLMILLET
FOLLOWING FOUR GREEN MANURE CROPS WITH AND
WITHOUT MAGNESIUM *.
(Harvested 7/23/52)
SYield
Green Manure Crop | Green Wt. I N K Ca I Mg I P
lbs./acre I% | % | % % %
No Magnesium

Native cover ......... 14,210 1.6 4.7 0.35 0.079 0.42
Oats .................... 16,430 1.8 4.9 0.37 0.105 0.58
Lupine ........... ........ 16,420 2.9 4.3 0.45 0.198 0.45
Sweetclover ..... .. 20,170 3.3 4.5 0.41 I 0.245 | 0.46
Magnesium

Native cover ............ 15,520 2.1 4.8 0.39 0.082 0.42
Oats ........................... 19,380 1.9 5.2 0.37 0.092 0.58
Lupine .....................-- 20,380 3.5 4.3 0.45 0.187 0.45
Sweetclover ............ 21,810 2.9 4.3 0.41 0.230 0.46
Elements as percentages of oven-dry forage.

Yields and analyses of pearlmillet which followed four green
manure crops the preceding winter are shown in Table 4. While
yields were much higher from plots which received magnesium
and minor elements, there was no difference in the magnesium
content of the pearlmillet as a result of the magnesium treat-
ment. However, the magnesium content of the pearlmillet fol-







8 Florida Agricultural Experiment Stations

lowing legumes was double that of pearlmillet following weeds
or oats. This difference apparently was due to the large amount
of magnesium in the legumes compared to that in the oats or
weeds.
The lupine, sweetclover and oats contained 0.192, 0.183 and
0.058 percent magnesium on an oven-dry basis, respectively.
These results suggest that leaching of magnesium may be a
serious problem and that a less readily soluble source of mag-
nesium would be preferable.
Data for sweetclover following the pearlmillet are shown in
Table 5. Yields were higher where magnesium was applied.
There were small differences in magnesium concentrations as a
result of its application. But differences were much larger
where the sweetclover followed legumes from the previous year.

TABLE 5.-YIELDS AND PERCENTAGES OF ELEMENTS IN SWEETCLOVER
FOLLOWING PEARLMILLET *.
(Harvested 3/25/53)
Yield
Green Manure Crop Green Wt. I N I K a I Mg P
Slbs./acre % % I % |% |%
No Magnesium

Native cover 10,140 2.3 1.8 0.76 | 0.205 0.24
Oats .................... 11,390 2.2 1.9 0.86 0.218 0.24
Lupine ........-.............. 10,820 2.2 1.7 0.72 0.217 0.24
Sweetclover ............ 12,090 2.5 1.7 0.70 0.219 0.24
Magnesium

Native cover .... 15,110 2.0 1.6 0.55 0.242 0.23
Oats ................ ..... 12,710 2.0 1.8 0.51 0.224 0.22
Lupine ...................... 14,590 2.2 1.8 0.55 0.271 0.24
Sweetclover ............ 14,850 2.5 1.6 0.71 0.286 0.23
Elements as percentages of oven-dry forage.

In a nitrogen study with oats on Klej fine sand, severe mag-
nesium deficiency was encountered with some nitrogen sources.
Sodium nitrate, ammonium nitrate, urea and anhydrous am-
monia were used. Rates of nitrogen were 50, 100 and 150
pounds per acre. The magnesium deficiency occurred where
ammonium nitrate and urea were applied. It was intensified by
increasing rates of application. No deficiency occurred where
sodium nitrate or anhydrous ammonia was applied. Relatively
lush growth of the oat forage was obtained with sodium nitrate,
but there was virtually no response to anhydrous ammonia in
the early stages of growth. Nitrification was relatively slow







Magnesium and Lime Needed in Suwannee Valley


in this soil and very little nitrate nitrogen was produced early
in the season from ammonia applied in the anhydrous form.
Judging from the speed of conversion of ammonia to nitrate
nitrogen, it may be concluded that the magnesium deficiency
occurred when the ammonium ion was present in the soil, but
only when nitrate nitrogen was applied, as with ammonium
nitrate, or where it was produced, as with urea, in sufficient
quantity for rapid plant growth.
Three of the plots which received 150 pounds per acre of nitro-
gen as urea and where the deficiency was most severe were split
on March 5, 1954. Half of each was sprayed with 200 pounds
of magnesium sulfate per acre. Evidence of magnesium de-
ficiency was considerably reduced. Average yields on April 6
were 620 and 1,260 pounds per acre of oven-dry forage for the
check and magnesium treatment, respectively. Plant magnesium
also was increased by the spray treatment, but was still com-
paratively low.
SOIL ANALYSIS
Magnesium, Calcium and pH Studies.-To determine the mag-
nesium status of soils in the area, 16 survey soil samples of
the'surface six inches, in addition to the two soils used for plant
studies, were taken from different locations, Figure 2.1 Seven
soil types were represented. All samples were taken from culti-
vated fields.
Analyses of these soils are shown in Table 6. Calcium, potash
and phosphate were low in most of the soils. The pH varied be-
tween 5.1 and 5.7. Total and extractable magnesium were low
in most soils. They were present in about the same quantities
as in soils studied in the pot and field experiments and shown
to be deficient for several forage plants (samples 8 and 13).
Sample 1 (Jonesville fine sand) contained relatively large quanti-
ties of both calcium and magnesium. This suggests that dolo-
mitic lime may have been applied.
Nitrification Rates.-In a laboratory nitrification study with
these soils, the results of which are shown in Table 7, the pro-
duction of nitrate nitrogen was very slow in many of the soils.
In some soils nitrification was not greatly improved by liming.
However, the fact that soil pH was usually low and that these
soils, without treatment other than ammonia, did not nitrify
is good evidence that lime is needed. The use of lime and fer-
1Soil types identified by Ralph G. Leighty, Associate Soil Surveyor,
Soils Department, Agricultural Experiment Station, University of Florida,
and Soil Scientist, U. S. Department of Agriculture.







Magnesium and Lime Needed in Suwannee Valley


in this soil and very little nitrate nitrogen was produced early
in the season from ammonia applied in the anhydrous form.
Judging from the speed of conversion of ammonia to nitrate
nitrogen, it may be concluded that the magnesium deficiency
occurred when the ammonium ion was present in the soil, but
only when nitrate nitrogen was applied, as with ammonium
nitrate, or where it was produced, as with urea, in sufficient
quantity for rapid plant growth.
Three of the plots which received 150 pounds per acre of nitro-
gen as urea and where the deficiency was most severe were split
on March 5, 1954. Half of each was sprayed with 200 pounds
of magnesium sulfate per acre. Evidence of magnesium de-
ficiency was considerably reduced. Average yields on April 6
were 620 and 1,260 pounds per acre of oven-dry forage for the
check and magnesium treatment, respectively. Plant magnesium
also was increased by the spray treatment, but was still com-
paratively low.
SOIL ANALYSIS
Magnesium, Calcium and pH Studies.-To determine the mag-
nesium status of soils in the area, 16 survey soil samples of
the'surface six inches, in addition to the two soils used for plant
studies, were taken from different locations, Figure 2.1 Seven
soil types were represented. All samples were taken from culti-
vated fields.
Analyses of these soils are shown in Table 6. Calcium, potash
and phosphate were low in most of the soils. The pH varied be-
tween 5.1 and 5.7. Total and extractable magnesium were low
in most soils. They were present in about the same quantities
as in soils studied in the pot and field experiments and shown
to be deficient for several forage plants (samples 8 and 13).
Sample 1 (Jonesville fine sand) contained relatively large quanti-
ties of both calcium and magnesium. This suggests that dolo-
mitic lime may have been applied.
Nitrification Rates.-In a laboratory nitrification study with
these soils, the results of which are shown in Table 7, the pro-
duction of nitrate nitrogen was very slow in many of the soils.
In some soils nitrification was not greatly improved by liming.
However, the fact that soil pH was usually low and that these
soils, without treatment other than ammonia, did not nitrify
is good evidence that lime is needed. The use of lime and fer-
1Soil types identified by Ralph G. Leighty, Associate Soil Surveyor,
Soils Department, Agricultural Experiment Station, University of Florida,
and Soil Scientist, U. S. Department of Agriculture.







Magnesium and Lime Needed in Suwannee Valley


in this soil and very little nitrate nitrogen was produced early
in the season from ammonia applied in the anhydrous form.
Judging from the speed of conversion of ammonia to nitrate
nitrogen, it may be concluded that the magnesium deficiency
occurred when the ammonium ion was present in the soil, but
only when nitrate nitrogen was applied, as with ammonium
nitrate, or where it was produced, as with urea, in sufficient
quantity for rapid plant growth.
Three of the plots which received 150 pounds per acre of nitro-
gen as urea and where the deficiency was most severe were split
on March 5, 1954. Half of each was sprayed with 200 pounds
of magnesium sulfate per acre. Evidence of magnesium de-
ficiency was considerably reduced. Average yields on April 6
were 620 and 1,260 pounds per acre of oven-dry forage for the
check and magnesium treatment, respectively. Plant magnesium
also was increased by the spray treatment, but was still com-
paratively low.
SOIL ANALYSIS
Magnesium, Calcium and pH Studies.-To determine the mag-
nesium status of soils in the area, 16 survey soil samples of
the'surface six inches, in addition to the two soils used for plant
studies, were taken from different locations, Figure 2.1 Seven
soil types were represented. All samples were taken from culti-
vated fields.
Analyses of these soils are shown in Table 6. Calcium, potash
and phosphate were low in most of the soils. The pH varied be-
tween 5.1 and 5.7. Total and extractable magnesium were low
in most soils. They were present in about the same quantities
as in soils studied in the pot and field experiments and shown
to be deficient for several forage plants (samples 8 and 13).
Sample 1 (Jonesville fine sand) contained relatively large quanti-
ties of both calcium and magnesium. This suggests that dolo-
mitic lime may have been applied.
Nitrification Rates.-In a laboratory nitrification study with
these soils, the results of which are shown in Table 7, the pro-
duction of nitrate nitrogen was very slow in many of the soils.
In some soils nitrification was not greatly improved by liming.
However, the fact that soil pH was usually low and that these
soils, without treatment other than ammonia, did not nitrify
is good evidence that lime is needed. The use of lime and fer-
1Soil types identified by Ralph G. Leighty, Associate Soil Surveyor,
Soils Department, Agricultural Experiment Station, University of Florida,
and Soil Scientist, U. S. Department of Agriculture.








Florida Agricultural Experiment Stations


TABLE 6.-ANALYSIS OF SURVEY SOIL SAMPLES FROM SUWANNEE
VALLEY AREA.


Soil Type


Ex-
change|
Capac-
ity I


m.e./
100
gms.

Jonesville f.s... 1.83
Jonesville f.s. .. 1.31
Jonesville f.s... 1.19
Lakeland f.s. 0.95
Lakeland f.s... 1.09
Arredondo f.s. 1.34
Ona f.s. _..... 1.65
Klej f.s .......... 1.69
Scranton f.s... 2.78
Klej f.s .......... 1.65
Archer f.s. ..... 1.25
Archer f.s ....... 1.23
Jonesville f.s. 1.35
Lakeland f.s. .. 0.83
Lakeland f.s... 1.17
Archer f.s...... 1.27
Jonesville f.s... 1.33
Jonesville f.s.. 1.27


Sam-
ple
No.


TABLE 7.-SOIL PH AND NITRATE NITROGEN AFTER 28 DAYS INCUBATION
WITH THREE LIME TREATMENTS ON SURVEY SOIL SAMPLES
FROM SUWANNEE VALLEY AREA.


I Current Crop



Corn ........ .........
Lupine stubble .........
Peanuts .........
Bahia grass ...........- .
SLupine ................
SPeanuts .
SBahia grass ...........
Oats ...---...........
Bahia grass .........
Oats .... .............
Corn ............................
I Corn .-..- -----.......... .......
W eeds ....---...... .....
I Corn .................... ...
L( .Li .. ........ ..............
I k --- ---- -
I C orn ...........................
I Corn ........- ..-
I


No Lime

pH INOs-N
Sppm
4.8 74.6
4.8 10.6
5.0 24.4
5.3 5.3
5.0 20.1
4.9 50.5
5.0 19.2
5.0 7.2
5.4 12.5
5.1 24.9
4.7 44.5
4.9 11.7
4.7 41.9
5.0 7.4
5.0 14.8
4.8 11.8
4.9 20.0
5.0 14.7


NHL Acetate Total
(pH 4.8) Extractable Mg
K20 Ca P OP 1Mg
ppm ppm ppm pp ppm pp ppm


39 272 17 37 78
8 64 8 20 27
18 111 2 26 24
14 108 13 16 34
16 96 9 21 27
21 136 14 55 77
34 111 10 14 31
59 20 13 4 38
24 122 7 9 45
30 72 9 5 42
31 200 6 25 33
26 48 6 14 22
48 208 13 14 31
13 16 6 5 23
18 96 8 15 26
18 136 5 13 14
12 60 12 11 29
10 108 14 21 I 35


1 Ton
SCalcium
Carbonate


Sam-
ple
No.


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18


pH


4.9
5.1
5.1
6.7
5.7


NNOs-N
I ppm
164.8
77.6
97.2
21.7
55.1
90.2
87.6
40.6
48.4
52.3
111.4
51.4
108.2
8.7
62.9
98.8
89.8
74.5


1 Ton
Dolomitic
Lime
pH INOs-N
I ppm
5.0 176.1
5.2 72.4
5.2 89.7
7.0 6.7
5.7 1 56.6
5.4 1100.4
5.2 86.2
5.7 31.6
5.6 30.0
5.6 45.9
5.1 107.7
6.0 46.0
4.9 100.5
6.5 i 14.9
5.4 54.2
4.8 107.5
5.2 70.7
5.4 73.5








Magnesium and Lime Needed in Suwannee Valley


tilizers usually promotes nitrification under field conditions.
Dolomitic lime and high calcium lime were equally effective in
improving nitrification.








12 18910
13
14 7
6
15 5
4



SAMPLING LOCATIONS
AND SOIL TYPES Y
I. JONESVILLE F.S.
2. JONESVILLE F.S.
3. JONESVILLE F.S.
4 LAKELAND F.S.
5 LAKELAND F. S.
6. ARREDONDO F.S.
7. NA F. S.
8.KLEJ F.S.
9. SCRANTON F. S.
10.KLEJ F. S.
Il.ARCHER F.S.
12.ARCHER F. 8.
13 JONESVILLE F S.
14 LAKELAND F. S. WELL DRAINED
15. LAKELAND F.S. SANDY SOILS
16. ARCHER F. S.
17. JONESVILLE F.S.
18. JONESVILLE F. S.


Fig. 2.-Location of survey samples.

DISCUSSION

Magnesium deficiency symptoms in forage plants were con-
sistently obtained on two soil types: Jonesville and Klej fine
sands. Plant magnesium concentrations were generally very
low. Magnesium applied in the sulfate form corrected the de-
ficiency symptoms and increased yields. Plant analytical data
showed that the loss of magnesium by leaching may have been
a serious factor, since the magnesium content of forage plants
was increased more by plowing down leguminous crops or by
adding inorganic salts to closed pots than by applying these salts






Florida Agricultural Experiment Stations


in the field. The only case where plant magnesium concentrations
approached those given by other workers (1, 2) was in plants
which were grown following leguminous green manure crops.
Analytical data for soils from several locations in the area
showed that pH and calcium and magnesium contents of most
of the soils were low. The nitrification rate of most of the soils
examined was relatively slow, but it usually showed some im-
provement when one ton of dolomitic or high calcium lime was
applied. Nitrogen sources containing ammoniacal nitrogen,
where nitrate nitrogen was present in the soil in sufficient
quantity for rapid plant growth, apparently reduced the plant
intake of magnesium to deficient amounts.
Magnesium is deficient in much of the soil of this area for
intensive crop production. There is little doubt that present
levels of production are sometimes limited by lack of magnesium.
This condition will become more serious as more extensive use
is made of adequate quantities of the major plant foods.
Since the reaction, the calcium and magnesium contents and
the nitrification rate of these soils are low, there is a definite
need for a liming material and magnesium to increase or im-
prove these soil factors. While magnesium sulfate and high
calcium lime can be used, the data suggest that, because of the
problem of leaching of magnesium and of pH control, a slowly
soluble source of magnesium, such as dolomitic lime, might be
better than soluble salts and high calcium lime.
Peech (5) and Volk (6) have stated that dolomitic lime is
relatively unreactive in the soil when the pH is raised above
6.0. This property makes it a safer material than high cal-
cium lime to use in correcting the reaction of light sandy soils
when used at reasonable rates. According to Volk (6), 1,000
pounds of high calcium lime per acre will raise the pH approxi-
mately one unit in soils of this area. Since dolomitic lime is
somewhat less reactive than high calcium lime, at least this
quantity would be necessary to change the soil pH from 5.0 to
6.0.
Lime for flue-cured tobacco appears to present somewhat of
a special situation. Most of the fertilizer experiments with
flue-cured tobacco have been conducted on soil having a pH of
5.7, according to Clark (3). In a report of the Agronomy
Tobacco Workers Conference in 1955 (4) it was stated that
flue-cured tobacco may be grown over a pH range of 5.2 to 6.2.
This report also stated that soils having a low calcium content
or a pH below 5.2 should be limed with dolomitic limestone.






Magnesium and Lime Needed in Suwannee Valley


RECOMMENDATIONS

The reaction of soils in the Suwannee Valley area generally
varies between pH 5.1 and 5.7. For most crops grown in the
area, except tobacco, and for adequate microbiological activity,
a reaction near pH 6.0 is desirable. Since a liming program
is needed for many soils in this area and since the magnesium,
calcium and pH of such soils are generally low, dolomitic lime
should be used. One thousand pounds of dolomitic lime per acre
generally will be a satisfactory application for these light-
textured soils, unless lime has been applied recently.
Since soil pH varies considerably from one field or farming
area to another, the safe procedure would be to take soil sam-
ples prior to liming and determine pH and magnesium and
calcium contents. Soil samples are analyzed and recommenda-
tions for soil treatment are made at the Soil Testing Laboratory,
Soils Department, Gainesville.

ACKNOWLEDGMENT
The authors gratefully acknowledge the assistance of personnel at the
Suwannee Valley Experiment Station in the field phases of this study, and
the help of Granville C. Horn and Paul H. Everett, Laboratory Assistants
in the Soils Department, in the laboratory phases.

LITERATURE CITED
1. BEESON, KENNETH C. The mineral composition of crops with particular
reference to the soils in which they are grown. U. S. Dept. Agr.
Misc. Pub. No. 369. 1941.
2. BENDER, WILLIAM H., and WALTER S. EISENMENGER. Intake of certain
elements by calciphilic and calciphobic plants grown on soils differ-
ing in pH. Soil Sci. 52: 297-305. 1941.
3. CLARK, FRED. Fertilizer tests with flue-cured tobacco. Fla. Agr. Exp.
Sta. Bul. 512. 1953.
4. CLARK, FRED, et. al. Recommendations with reference to the fertiliza-
tion of flue-cured tobacco grown on average soils in Virginia, North
Carolina, South Carolina, Georgia and Florida. Mimeographed
report prepared by advisory committee of the Agronomy Tobacco
Workers Conference, Richmond, Virginia. January, 1955.
5. PEECH, M. Chemical studies on soils from Florida citrus groves. Fla.
Agr. Exp. Sta. Bul. 340. 1939.
6. VOLK, G. M., and NATHAM GAMMON, JR. Soil reaction (pH). Fla. Agr.
Exp. Sta. Cir. S-39. 1951.




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