• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Experimental procedure
 Continuous crop and rotation...
 Fertilizer experiment
 Lime experiment
 Effect of lime on rotations
 Harvesting versus hogging-off...
 Applying fertilizer to present...
 Chemical content of soils...
 Nematode studies
 Summary and conclusions
 Acknowledgement
 Literature cited














Group Title: Bulletin University of Florida. Agricultural Experiment Station
Title: Effect of rotations, fertilizers, lime and green manure crops on crop yields and on soil fertility, 1947-1957
CITATION DOWNLOADS THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026844/00001
 Material Information
Title: Effect of rotations, fertilizers, lime and green manure crops on crop yields and on soil fertility, 1947-1957
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 60 p. : ill. ; 23 cm.
Language: English
Creator: Thompson, L. G ( Leonard Garnett ), 1903-
Robertson, W. K ( William Kendrick )
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1959
Copyright Date: 1959
 Subjects
Subject: Soil fertility -- Florida   ( lcsh )
Crop yields -- Florida   ( lcsh )
Crop rotation -- Florida   ( lcsh )
Liming of soils -- Florida   ( lcsh )
Green manure crops -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: L.G. Thompson, Jr., W.K. Robertson.
Bibliography: Includes bibliographical references (p. 60).
General Note: Cover title.
 Record Information
Bibliographic ID: UF00026844
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AEN7744
oclc - 18302036
alephbibnum - 000927041

Downloads
Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Experimental procedure
        Page 3
    Continuous crop and rotation experiment
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Fertilizer experiment
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
    Lime experiment
        Page 23
        Page 24
    Effect of lime on rotations
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
    Harvesting versus hogging-off peanuts
        Page 33
    Applying fertilizer to present versus preceding crop
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
    Chemical content of soils and plants
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
    Nematode studies
        Page 57
    Summary and conclusions
        Page 57
        Page 58
    Acknowledgement
        Page 59
    Literature cited
        Page 60
Full Text


Bulletin 614 December 1959



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








Effect of Rotations, Fertilizers, Lime and

Green Manure Crops on Crop Yields

And on Soil Fertility, 1947-1957


L. G. THOMPSON, JR.
Soils Chemist, North Florida Experiment Station, Quincy
W. K. ROBERTSON
Associate Chemist, Main Station, Gainesville



Fig. 1.-Corn and peanuts grown in rotation.





I






t r


L 4 ,
1 ^ ^.v '*,.h ** *






















CONTENTS
Page

EXPERIMENTAL PROCEDURE ....---.......... --------............ ----....... 3

CONTINUOUS CROP AND ROTATION EXPERIMENT .....---------...........---.........----- 4

FERTILIZER EXPERIMENT --.............--- ----.....-- ....... ....-............... 13

LIME EXPERIMENT ................. ........................ ........ ................- ... 23

EFFECT OF LIME ON ROTATIONS ........-----. ...---------....------------ 25

HARVESTING VERSUS HOGGING-OFF PEANUTS ----........................ ..---...... 33

APPLYING FERTILIZER TO THE PRESENT CROP VERSUS APPLYING
FERTILIZER TO THE PRECEDING CROP ...............--- --......................-- 33

CHEMICAL CONTENT OF SOILS AND PLANTS .........-----...---.......---....---- 39

NEMATODE STUDIES----- ----------...................------.-----.- 57

SUMMARY AND CONCLUSIONS ................-.........---- --------------- 57

ACKNOWLEDGMENTS .. --.................... ..---...... --..-----... ......... 59

LITERATURE CITED ...... --------.. .... ----- ---------............... 60










Effect of Rotations, Fertilizers, Lime and

Green Manure Crops on Crop Yields

And on Soil Fertility, 1947-1957

L. G. THOMPSON, JR. and W. K. ROBERTSON

Two crops, corn and peanuts, occupy a large percentage of
the cultivated land in North and West Florida. The acute
shortage of edible oil during and in the reconversion period
following World War II resulted in high prices for peanuts
and, consequently, a substantial increase in acreage for harvest.
To obtain this increase in acreage, many farmers planted peanuts
on the same land year after year. This practice seriously de-
pleted organic matter and lowered soil fertility. On such soils
both peanut and corn yields showed a progressive decline.
The investigation reported here was conducted to determine
the effect of various rotations, fertilizers, lime and green manure
crops on the yield of peanuts, corn, soybeans and oats, and on the
fertility of Norfolk loamy fine sand. This is one of the major
soil types used for general farm crops in North Florida, consti-
tuting more than 10% of the cropland. Data obtained on this
soil type are applicable in general to several closely related soils
such as Red Bay fine sandy loam and Ruston fine sandy loam
which occupy approximately 50% of the cropland. These experi-
ments were continued 11 years and results for the first 5 years
were published in Bulletin 522 (8). This bulletin summarizes
results for the 11 years these experiments have been in progress.

EXPERIMENTAL PROCEDURE
A 40-acre field of virgin Norfolk loamy fine sand was surveyed
into field blocks and plots during the winter of 1946-47. Rotation,
fertilizer, lime and "hogged-off" peanut experiments, each in
randomized blocks replicated 4 times, were initiated in the spring
of 1947. A soil sample was taken from each individual plot
before any fertilizer or lime was applied. As the experiment
progressed, soil samples were taken from time to time to study
the changes brought about in the soil.
Red Rustproof No. 14 oats were planted the first 3 years,
Southland oats the next 5 years, Seminole oats the next year
and Floriland oats the last year. As winter and summer cover







4 Florida Agricultural Experiment Stations

crops, respectively, bitter blue lupine and Crotalaria spectabilis
were planted the first 5 years, Alta blue lupine and Clemson
Non-shatter soybeans the next 4 years, and Alta blue lupine and
Lee soybeans the last 2 years. Florida W-1 hybrid corn was
planted the first 2 years and Dixie 18 hybrid corn the last 9 years
of the experiment. Dixie runner peanuts were used throughout
the experiment.
The lupine, soybeans and, in some of the cropping systems,
oats were turned under for green manure. Corn was harvested
and yields were reported as bushels per acre on 17%o moisture
basis. The stalks and native cover which grew in the corn were
turned under. Both peanuts and vines were removed from the
land. Peanut yields were reported as pounds per acre of unshell-
ed nuts.
The fertilizer used in all experiments was made from Uramon
(42 percent N), superphosphate (18 percent P205), and muriate
of potash (60 percent K20), except for the last 6 years when
ammonium nitrate (33.5 percent N) replaced Uramon. Corn re-
ceived 10 pounds of zinc sulfate per acre annually, except for the
last 3 years. Peanuts in all experiments were dusted 3 to 4
times each season with 20 pounds of elemental sulfur-DDT mix-
ture per acre.
Each experiment was plowed by blocks. The direction of
plowing was reversed every other time to minimize border effect.

CONTINUOUS CROP AND ROTATION EXPERIMENT
The continuous crop 1 and rotation experiment consisted of
6 continuous crops, 3 2-year rotations and 2 3-year rotations.
A list of continuous crops and rotations appears with the yield
data in Tables 1 and 2. Each crop in the 2- and 3-year rotations
was grown every year. The 2-year rotations were alternated
between 2 series of plots, the 3-year rotations among 3 series.
Each year corn and oats for grain received 500 pounds per
acre of 2-10-8 fertilizer at planting time. For the first 5 years
corn was top-dressed with 32 pounds per acre of nitrogen from
Uramon and oats with 32 pounds from nitrate of soda. Corn
for the last 6 years and oats for the last 5 years were top-dressed
with 32 pounds per acre of nitrogen from ammonium nitrate.
Oats turned under received annual applications of 500 pounds
per acre of 2-10-8 fertilizer the first 3 years and no fertilizer
"1"Continuous crop" refers to a crop planted on the same area in suc-
cessive years.






TABLE 1.-ANNUAL YIELDS OF CORN, 1947 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATIONS.

Yield of Corn (Bushels per Acre)
Rotation -
Rotan 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average

Continuous corn:
Corn only ..........................---- 42 36 58 58 49 29 42 33 48 48 61 46
Corn with crotalaria*, oats* 48 42 74 79 64 34 47 36 49 50 58 53
Corn with crotalaria* ............ 48 39 70 82 62 35 50 38 51 55 67 54
Corn with lupine* ........................ 42 41 67 75 57 37 49 39 52 63 62 53

Average ............... .................. 45 39 67 74 58 34 47 36 50 54 62 52

2-year:
Peanuts, lupine*, corn ................ 43 49 72 84 62 42 49 41 52 58 58 55
Peanuts, lupine*, corn with
velvet beans ............................. 38 45 69 75 59 36 50 40 51 57 58 53
Peanuts, lupine*, corn with
crotalaria* 45 50 74 83 64 40 54 41 51 54 58 56

Average ................................. 42 48 72 81 62 39 51 41 51 56 58 55

3-year: "*
Peanuts, lupine*, corn, lupine* .... 42 48 74 87 63 41 53 40 53 64 57 57
corn, oats* .................... ............. 43 44 69 82 69 36 50 42 53 58 68 56
Peanuts, lupine*, corn, oats for
grain, crotalaria*, oats* -- 45 44 80 93 64 39 59 40 55 63 59 58

Average .................-.............. 43 45 74 87 65 39 54 41 54 62 61 57

L. S. D. (.05) ................ ................ 5 6 5 8 6 4 N.S.** 4 IN.S.** 3 N.S.**
L. S. D. (.01) ...................................... 7 8 7 11 8 6 6 4
Crops plowed under as green manure. Beginning in 1952, crotalaria was replaced by soybeans.
** N. S. signifies not significant. CJ










TABLE 2.-ANNUAL YIELDS OF PEANUTS, 1947 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATIONS.

_- Yield of Peanuts (Pounds per Acre) Average
Rotation II Last 6
1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Years

Continuous peanuts:
Peanuts only 1,900 1,470 820 1,360 2,010 790 740 490 780 580 650 670
Peanuts, lupine* 1,940 1,360 900 1,360 1,890 740 540 410 820 640 460 600

Average 1,920 1,420 860 1,360 1,950 760 600 450 800 610 560 640

2-year:
Peanuts, lupine* 1,740 1,660 1,080 1,390 2,220 1,310 1,220 900 1,270 920 1,060 1,110
Corn
Peanuts, lupine* 1,890 1,670 990 1,360 2,410 1,330 1,120 940 1,380 1,110 890 1,130
Corn with velvet beans
Peanuts, lupine* 1,810 1,700 1,060 1,690 2,340 1,460 1,080 1,010 1,350 1,040 1,060 1,170
Corn with crotalaria

Average 1,810 1,680 1,040 1,480 2,320 1,370 1,140 950 1,330 1,020 1,010 1,140

3-year:
Peanuts, lupine* 1,960 1,800 1,050 1,440 2,200 1,520 1,530 1,220 1,620 1,080 1,000 1,330
Corn, lupine*
Corn, oats*
Peanuts, lupine* 1,920 1,730 1,020 1,540 2,310 1,590 1,560 1,300 1,880 1,190 930 1,410
Corn, oats for grain
Crotalaria*, oats*

Average [ 1,940 1,760 1,040 1,490 2,260 1,560 1 1,540 1,260 1,750 1,130 9701 1,370

L. S. D. (.05) N.S. 230 180 280 220 250 130 172 250 130 190
L. S. D. (.01) 320 250 N.S. 310 340 170 240 340 180 270
Crops plowed under as green manure. Beginning in 1952 crotalaria was replaced by soybeans.







Effect of Fertilizers, Lime and Green Manure 7

the last 7 years. Peanuts were fertilized with 400 pounds of
2-10-4 per acre for the first 3 years and 500 pounds of 2-10-8
fertilizer the last 8 years of the test. Blue lupine and crotalaria
received 300 pounds per acre of 0-14-10 the first 3 years and no
fertilizer during the last 7 years. Soybeans were not fertilized.
Yields of corn are shown in Table 1. Compared with the
average of all continuous corn treatments, 2-year rotations
averaged 3 bushels higher, and 3-year rotations 5 bushels
higher for the 11 years. However, continuous corn interplanted
with crotalaria or followed by oats or lupine yielded only slightly
less than 2-year rotations and 6 to 8 bushels more than contin-
uous corn with no cover crop. The 2-year rotations averaged
9 bushels more and the 3-year rotations 11 bushels more than
continuous corn with no cover crop. For all years except 1947,
1953, 1955 and 1957, the rotations gave a highly significant
increase in yield of corn over continuous corn without a cover
crop and in these years the trend was in favor of the 2- and
3-year rotations. In 1950, after the largest lupine cover crop
of the 10 years reported (Table 4), rotation corn yielded 23 to
35 bushels more than continuous corn with no cover crop (Fig-
ure 2).
Figure 3 shows the relationship between total rainfall in
May, June and July and corn yield from the 3-year rotation of
peanuts, lupine, corn, oats for grain, crotalaria and oats, for
1949 through 1957. The correlation coefficient was 0.762, which
was significant at the 5 percent level. These results indicate

Fig. 2.-Left: Corn grown in 1950 after 4 years in a 3-year rotation
of peanuts, lupine for green manure, corn, oats for grain, crotalaria and
oats for green manure. Yield 93 bushels per acre. Right: Corn grown con-
tinuously for 4 years. Yield 58 bushels per acre.

















" "1 . . .:
Q , ''







8 Florida Agricultural Experiment Stations

that rainfall distribution (Table 39) is a very important factor
in growing corn in North Florida.


D 22
-90
ILI
20 \

S-80 -

i -


:: 18 \ (
o x Ax 60

12- \
< /50 >-
I'I /

()n X--X YIELD
W
IJ

Z 1949 1950 1951 1952 1953 1954 1955 1956 1957
YEAR
Fig. 3.-Relationship between rainfall and average yield of corn from
the rotation of peanuts, lupine, corn, oats for grain, crotalaria and oats,
1949 through 1957.

Yields of peanuts are given in Table 2. For the first 5 years
the average yield of peanuts was about 200 pounds higher on
the rotation than on the continuous peanut plots; yields were
about the same in the 2- and 3-year rotations. For the last 6
years the average yield of peanuts was 500 pounds higher on
the 2-year rotations and 730 pounds higher on the 3-year rota-
tions than on the continuous plots (Figures 4 and 5).
Average yield of peanuts for the last 6 years was 80 pounds
higher for the 3-year rotation of peanuts, lupine, corn, oats for
grain, soybeans, oats, than for the 3-year rotation of peanuts,
lupine, corn, lupine, corn, oats. However, it may not be the best
rotation, because there is only 1 instead of 2 corn crops for the
3 years. But, if the soybeans were used for seed instead of green
manure, they might compensate for the corn crop.
During the last 6 years there was more disease in the con-
tinuous peanuts than in the peanuts grown in the 2-year rotation,








Effect of Fertilizers, Lime and Green Manure 9


TABLE 3.-ANNUAL YIELDS OF CROTALARIA AND VELVET BEANS, 1947
THROUGH 1952, WHEN PLANTED IN VARIOUS ROTATIONS.

Green Wt. of Crotalaria-1,000 Lbs. per Acre
Rotation I 5
_____Ron 1947 1948 1949 1950 1951 1952 Average

Continuous corn:
With crotalaria*, oats* 13.6 23.6 10.7 5.6 1.5 8.6 10.6
With crotalaria* ........ 12.7 22.3 10.0 2.5 1.2 6.7 9.2

2-year:
Peanuts, lupine* 12.8 17.9 11.3 8.3 5.1 4.7 10.0
Corn with crotalaria

3-year:
Peanuts, lupine* 22.6 34.2 28.0 11.7 6.6 13.7 19.5
Corn, oats for grain
Crotalaria*, oats*

L. S. D. (.05) 1.6 3.0 2.8 3.3 4.1 2.6 I
L. S. D. (.01) 2.3 4.3 4.0 4.8 N.S. 3.8 ]

Dry Shelled Velvet Beans-Lbs. per Acre

2-year:
Peanuts, lupine*
Corn with velvet beans 941 420 1 304 1,472 859 438 739
Crops plowed under as green manure. In 1952, crotalaria was replaced by soybeans.


Fig. 4.-Peanut crop in 1953 after 7 years of continuous cropping. Stand
and vegetative growth were poor. Average yield was 600 pounds per acre.





















""L
**.' 4;ii:








10 Florida Agricultural Experiment Stations

and no disease was observed in the peanuts grown in a 3-year
rotation. Because of diseases common to peanuts and lupine,
such as Rhizoctonia spp. and Sclerotium rolfsii Sacc., the average
yield of peanuts for the last 6 years was lower following cover
crops of lupine than following no cover crop.
Crotalaria and velvet beans were broadcast in the corn just
before last cultivation. Green weights of crotalaria and weights
of dry shelled velvet beans are shown in Table 3. Crotalaria
yields were highest the second year, probably because of resid-
ual fertilizer from the first 2 crops and no competition from
weeds. Crotalaria made very poor growth in 1951 and soybeans
were planted instead in 1952. They made poor growth because
of weeds and shade from the corn for that year and later years.
When planted in rows and cultivated, soybeans after oats for
grain produced 11,000 to 17,000 pounds per acre of green forage.
For the first 6 years velvet beans were planted with the
corn. The stand of corn was not reduced, but the corn yield
was reduced 3 to 9 bushels. Velvet beans yielded 304 to 1,472
pounds of dry shelled beans per acre. Consequently total yield
of both crops averaged much larger than corn alone.
Yields of lupine are given in Table 4. Lupine made poor
growth in 1952, 1953 and 1954, but the growth was better in
1955 and 1956. For the last 5 years lupine following continuous
peanuts made the lowest yield, probably because of diseases
common to both crops, such as Rhizoctonia spp. and Sclerotium
rolfsii Sacc. Many of the lupine plants died and those that lived
made a poor growth (Figure 6). When lupine was grown only
once in a 3-year rotation, the increase in yield over continuous
cropping was highly significant (Figure 7). Lupine following
continuous corn yielded as much or more than lupine grown in

Fig. 5.-Peanut crop in 1953 after 7 years of a 3-year rotation of peanuts,
lupine for green manure, corn, oats for grain, crotalaria and oats for green
manure. Yield averaged 1,560 pounds per acre.








TABLE 4.-YIELDS OF LUPINE FROM 1948 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATIONS.

Green Weight of Lupine-1,000 Pound per Acre** Avg. Last
Rotation 5 Years
1948 1949 1950 1952 1953 1954 1955 1956 _

Continuous:
Peanuts, lupine* 11.7 2.7 15.8 2.2 0.5 0.6 4.3 5.9 2.7
Corn, lupine* 11.6 5.6 17.6 7.0 1.7 6.2 10.6 12.5 7.6


2-year:
Peanuts, lupine* 12.0 8.8 15.0 3.6 2.1 2.1 10.5 10.2 5.7
Corn
Peanuts, lupine* 11.4 9.2 15.7 3.5 2.0 2.6 9.3 9.8 5.4
Corn and velvet beans
Peanuts, lupine* 11.6 9.2 14.9 2.6 2.4 1.8 10.8 9.3 5.4
Corn with crotalaria*


3-year:
Peanuts, lupine* 12.1 10.0 18.3 5.0 2.3 3.5 10.5 11.0 6.5
Corn, lupine* 14.5 2.9 16.3 7.3 1.8 5.5 10.6 10.6 7.2
Corn, oats*
Peanuts, lupine* 10.2 10.2 19.0 8.4 2.0 6.4 10.3 12.3 7.9
Corn, oats for grain
Crotalaria*, oats*


L. S. D. (.05) 2.5 2.5 2.8 2.2 0.8 2.9 3.1 2.1
L. S. D. (.01) 3.4 3.4 3.8 2.8 1.1 3.9 4.2 2.7
Crops plowed under as green manure.
** Severe freezes in February completely killed the lupine in 1951 and 1957.











TABLE 5.-ANNUAL YIELD OF OATS, 1948 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATIONS.

Green Weight of Oats-1,000 Pounds per Acre
Rotation
_1948 1949 1950 1951** 1952 1953 1954 1955 1956 1957 Average

Continuous corn:
With crotalaria*, oats* 8.9 18.0 14.8 5.6 5.0 2.3 3.5 5.4 4.6 7.6


3-year:
Peanuts, lupine*
Corn, lupine*
Corn, oats* 7.0 11.2 10.7 5.8 4.8 2.8 4.1 8.7 5.6 6.7

Peanuts, lupine*
Corn, oats for grain
Crotalaria*, oats* 10.6 21.0 17.4 5.1 5.1 8.4 8.1 15.0 7.1 10.9
Average


L. S. D. (.05) 1.0 3.4 4.4 N.S. N.S. 1.4 1.6 4.0 1.4
L. S. D. (.01) 1.5 5.2 6.7 2.1 2.4 6.1 2.1
Oats for Grain-Bushels per Acre

3-year: 2
Peanuts, lupine*
Corn, oats for grain 26 21 43 83 66 52 23 19 lost 33 41
Crotalaria*, oats*

Crop plowed under as green manure. Beginning in 1952, crotalaria was replaced by soybeans.
** A severe freeze in February killed the top growth, making harvest impractical in 1951.








Effect of Fertilizers, Lime and Green Manure 13

rotation. In 1950, 1952, 1954 and 1956 lupine grown in a 3-year
rotation yielded significantly more than lupine in a 2-year ro-
tation. These results indicate that lupine does better following
peanuts if grown in a 3-year rotation.
Yields of oats for green manure are shown in Table 5. In
the 3-year rotation where soybeans were grown as a cash crop
they improved yields of oats, probably due to the nitrogen left
after the soybeans were harvested. But when oats followed
soybeans grown as an intercrop in continuous corn, yields were
low. In the latter case soybean growth was poor due to weed and
shade by the corn and hence contributed very little residual
nitrogen for the oat crop that followed. Crown rust reduced
the yield of Southland oats for grain in 1954 and 1955.

FERTILIZER EXPERIMENT
The treatments for the fertilizer experiment consisted of
3 general levels of fertility and 3 levels each of nitrogen (N),
phosphoric acid (P2O,) and potash (K,O) arranged in a random-
ized block design with 4 replications. Treatments were made to
all crops in a 3-year rotation consisting of peanuts, lupine under,
the first year; corn, oats for grain, the second year; and crota-
laria under, oats under the third year. This was done by having
3 sets of plots for each treatment and rotating the crops among
them. Since a different crop was planted on each set of plots

Fig. 6.-Lupine in 1952 after continuous peanuts for 5 years. Yield
averaged 2,200 pounds green weight per acre.














o-
9~? ~~~

.I p~c. W


A ,I~=








14 Florida Agricultural Experiment Stations

the first year, all crops received all treatments every year. All
plots received 2 tons of calcic lime. This was given in 1 appli-
cation to all crops except peanuts in 1957. Peanuts received
the 2 tons of lime in a split application, half in 1956 and half
in 1957.
The rates of fertilizer applied to each crop are shown with
the yield data in Tables 6 to 11.
Yields of corn with various rates of fertilizer are given in
Table 6. Increasing nitrogen, phosphate and potash from the
low to the medium rate increased yield of corn 9 bushels per
acre for an 11-year average. Increasing these 3 fertilizers to
the high rate increased corn yield an additional 5 bushels per
acre. With phosphate and potash at the high rate, increasing
nitrogen from the low to the medium rate increased the yield
of corn only 2 bushels per acre; and a further increase of nitrogen
to the high rate increased the yield of corn only 1 bushel per
acre for an 11-year average. Since all the green manure crops
in this rotation were fertilized, they produced relatively good
growth and added considerable nitrogen to the soil. Therefore,
only a small amount of extra nitrogen was needed to produce
a high yield of corn.
With nitrogen and potash at the high rate, increasing phos-
phate from the low to the medium rate increased yield of corn
6 bushels per acre, and a further increase to the high rate in-
creased the yield 3 bushels per acre.

Fig. 7.-Lupine in 1952 after 5 years in a 3-year rotation. Yield averaged
8,400 pounds green weight per acre.















-.- --











TABLE 6.-CORN YIELDS FROM 1947 THROUGH 1957 WITH VARIOUS ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Yield of Corn-Bushels per Acre

N P2Os KgO 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average

21 25 20 29 38 60 80 64 32 61 34 52 60 68 53
42 50 40 42 48 75 97 67 33 76 45 57 69 76 62
63 75 60 50 50 84 100 68 36 86 44 62 74 82 67

21 75 60 41 44 78 96 71 38 81 44 60 72 74 64
42 75 60 47 50 82 102 68 34 83 44 61 77 79 66
63 75 60 50 50 84 100 68 36 86 44 62 74 82 67

63 25 60 33 41 73 88 66 32 74 38 54 66 69 58
63 50 60 43 47 82 95 69 33 78 43 60 69 80 64
63 75 60 50 50 84 100 68 36 86 44 62 74 82 67

63 75 20 47 47 79 90 69 29 74 42 60 70 82 62
63 75 40 47 48 84 98 70 34 87 45 59 76 80 66
63 75 60 50 50 84 100 68 36 86 44 62 74 82 67


L. S. D. (.05) 5 6 5 8 6 4 7 4 4 4 6
L. S. D. (.01) 7 8 7 11 N.S. N.S. 10 6 5 5 8
__



1-*







16 Florida Agricultural Experiment Stations

Where nitrogen and phosphate were high, increasing potash
from the low to the medium rate increased the yield of corn 4
bushels per acre, and a further increase to the high rate increased
the yield of corn an average of only 1 bushel per acre for 11 years.
Since lupine which was plowed under for corn was well ferti-
lized and returned to the soil considerable phosphate and potash,
there was not a large response to phosphate and potash above
the medium rate.
Under the conditions of this experiment, when corn was
grown in a 3-year rotation with all the crops fertilized, the high
rate of the 3 major nutrients, nitrogen (63 pounds per acre),
phosphate (75 pounds per acre) and potash (60 pounds per acre)
are required for good corn.



/ I 90

I s
/ ,

\ 0\ 80

_J 18\

IE



I -0 RAINFALL 40 0
0 14 \i')






X---X YIELD
W 12 W
< 50





Fig. 8.-Relationship between rainfall and yield of corn from the highest
Fig 8 s te 0--0u RAINFALL a40 co
y f X--Xr YIELD

Z 1949 1950 1951 1952 1953 1954 1955 1956 1957

YEAR
Fig. 8.-Relationship between rainfall and yield of corn from the highest
rate of fertility in the fertilizer experiment, 1949 through 1957.

Figure 8 shows the relationship between rainfall and corn
yields from the highest rate of fertility in the fertilizer experi-
ment for 1949 through 1957. The correlation coefficient was
0.87, which was significant at the 5 percent level. These results
indicate that rainfall distribution is a very important factor











TABLE 7.-PEANUT YIELDS FROM 1947 THROUGH 1957 WITH VARIOUS ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Yield of Unshelled Peanuts-Pounds per Acre

N P205 K20 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average

4 20 8 1,660 1,920 1,420 1,670 2,620 1,740 1,560 1,750 2,100 1,570 1,090 1.740
8 40 16 2,140 2,240 1,210 1,640 2,370 1,560 1,430 1,720 1,810 1,420 980 1,680
12 60 24 2,250 2,100 1,150 1,520 2,340 1,530 1,220 1,570 1,640 1,320 900 1,590

4 60 24 2,440 1,990 1,280 1,530 2,350 1,670 1,320 1,620 1,810 1,350 940 1,660
8 60 24 2,450 2,000 1,190 1,530 2,300 1,470 1,300 1,560 1,800 1,320 940 1,620
12 60 24 2,250 2,100 1,150 1,520 2,340 1,530 1,220 1,570 1,640 1,320 900 1,590

12 20 24 1,740 2.030 1,290 1,490 2,110 1,450 1,240 1,350 1,880 1,330 1,000 1,540
12 40 24 2,160 2,030 1,270 1,540 2,260 1,460 1,280 1,460 1,800 1,400 860 1,590
12 60 24 2,250 2,100 1,150 1,520 2,340 1,530 1,220 1,570 1,640 1,320 900 1,590

12 60 8 2,300 2,130 1,260 1,680 2,250 1,440 1,420 1,540 1,850 1,350 1,050 1,660
12 60 16 2,400 2,060 1,190 1,700 2,390 1,500 1,360 1,620 1,840 1,320 950 1,670
12 60 24 2,250 2,100 1,150 1,520 2,340 1,530 1,220 1,570 1,640 1,320 900 1,590


L. S. D. (.05) 170 250 N.S. N.S. N.S. N.S. 150 170 190 N.S. 60
L. S. D. (.01) 230 N.S. 200 230 260 N.S.
kbl


I.l








18 Florida Agricultural Experiment Stations


TABLE 8.-CROTALARIA YIELDS FROM 1947 THROUGH 1951 WITH VARIOUS
ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Green Weight of Crotalaria-1,000 Pounds per Acre

PMO, K2O 1947 1948 1949 1950 1951 Average

21 15 10.5 27.0 25.0 4.7 5.7 14.6
42 30 15.1 38.6 27.8 8.2 10.4 20.0
63 45 22.5 38.9 29.5 11.1 10.7 22.5

21 45 11.2 31.9 26.9 7.2 8.7 17.2
42 45 22.9 37.7 28.7 9.1 9.5 21.6
63 45 22.5 38.9 29.5 11.1 10.7 22.5

63 15 22.0 39.6 26.8 11.6 11.4 22.3
63 30 22.2 37.8 29.2 9.4 10.4 21.8
63 45 22.5 38.9 29.5 11.1 10.7 22.5


L. S. D. (.05) 1.8 4.5 2.0 3.0 3.8
L. S. D. (.01) 2.5 6.2 2.7 4.1 N.S.





TABLE 9.-SOYBEAN YIELDS FROM 1952 THROUGH 1957 WITH VARIOUS
ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Green Weight of Soybeans-1,000 Pounds per Acre

N PsOs KrO 1952 1953 1954 1955 1956 1957 Average

16 21 15 9.0 16.2 9.6 10.4 10.2 17.0 12.1
32 42 30 12.0 21.4 13.6 14.2 13.2 20.1 15.8
48 63 45 17.5 23.7 15.8 18.6 17.0 20.3 18.8

16 63 45 12.2 22.1 12.8 16.8 15.4 17.2 16.1
32 63 45 13.9 20.8 15.3 16.0 15.8 17.7 16.6
48 63 45 17.5 23.7 15.8 18.6 17.0 20.3 18.8

48 21 45 11.5 17.5 12.2 14.2 10.2 18.0 13.9
48 42 45 15.1 20.3 13.5 17.1 12.9 19.3 16.4
48 63 45 17.5 23.7 15.8 18.6 17.0 20.3 18.8

48 63 15 14.0 17.7 14.9 16.3 12.7 18.8 15.7
48 63 30 15.1 20.9 15.3 17.0 14.2 19.6 17.0
48 63 45 17.5 23.7 15.8 18.6 17.0 20.3 18.8


L. S. D. (.05) 4.6 2.7 2.1 2.9 2.1 1.8
L. S. D. (.01) N.S. 3.6 2.8 3.9 2.8 2.4










TABLE 10.-OAT YIELDS FROM 1948 THROUGH 1957 WITH VARIOUS ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Green Weight of Oats-1,000 Pounds per Acre*__

N P205 K20 1948 1949 1950 1952 1953 1954 1955 1956 1957 Average '

5 25 20 5.3 7.9 9.8 4.1 5.7 5.5 3.4 13.1 4.5 6.6
10 50 40 6.9 14.2 15.9 5.6 8.9 7.9 7.5 21.8 6.5 10.6
15 75 60 10.6 22.5 19.9 10.4 12.5 11.0 12.2 29.7 10.8 15.5
5 75 60 8.6 15.4 16.1 5.3 5.5 9.4 7.2 29.4 9.5 11.8
10 75 60 9.1 19.2 17.2 8.8 10.4 10.1 11.6 27.8 9.3 13.7
15 75 60 10.6 22.5 19.9 10.4 12.5 11.0 12.2 29.7 10.8 15.5
15 25 60 6.7 12.1 11.9 7.9 6.1 6.0 4.8 17.6 4.8 8.6
15 50 60 9.3 17.4 19.7 9.6 9.9 8.0 9.3 23.0 6.9 12.6
15 75 60 10.6 22.5 19.9 10.4 12.5 11.0 12.2 29.7 10.8 15.5
15 75 20 10.5 17.0 15.4 9.2 9.8 8.7 11.3 22.2 6.7 12.3
15 75 40 9.9 19.3 17.9 9.3 10.5 10.3 11.0 23.7 8.6 13.4
15 75 60 10.6 22.5 19.9 10.4 12.5 11.0 12.2 29.7 10.8 15.5

L. S. D. (.05) 0.7 3.4 3.8 2.8 2.2 2.3 2.0 2.0 2.0
L. S. D. (.01) 1.0 4.6 5.1 3.8 3.0 3.1 2.7 2.7 2.8

A severe frost in February killed the top growth, making harvest impractical in li51l.








20 Florida Agricultural Experiment Stations

in corn production in North Florida. They also indicate that
there is more response to fertilizer when moisture is favorable
than in dry years.
Peanut yields from the fertility experiment are shown in
Table 7. When grown in a 3-year rotation where all the crops
are well fertilized, peanuts did not respond consistently to ferti-
lizer. After the first 2 years the yield decreased with increased
rates of fertilizer. This might have been due to application in
the row which affected germination or growth. Negative re-
sponses to potash have been found elsewhere (7). The decline
in yield was usually larger for the last increment than the
second.
Yields of crotalaria with various rates of fertilizer are given
in Table 8. Phosphate gave a significant increase in yield of
crotalaria for each year except the last. The results show that
when crotalaria was grown in rotation where the other crops
were well fertilized, there was probably enough residual ferti-
lizer, except for phosphate, to produce good growth.
The effect of fertility rates on soybean yields appear in Table
9. Phosphate gave significant increase in the yield of soybean
forage for 6 years, potash for 2 years and nitrogen for 3 years.
The nitrogen was applied in February, but it increased the yield
of soybeans planted in June. For the years when nitrogen gave
yield increases it is possible that inoculation might not have
been fully effective.
Yields of oats for green manure with various rates of fer-
tilizer are presented in Table 10. Nitrogen gave a significant
increase in yield of oats for 6 years out of 10, phosphate for
9 years and potash for 6 years. It is apparent that rates of fer-
tilizer application were insufficient to give maximum yields.
Yield data to show the effects of rates of fertility on yields
of blue lupine are shown in Table 11. In 4 years out of 8, in-
creasing 0-14-10 fertilizer from 150 to 300 pounds per acre
doubled the green weight yield of lupine. Increasing this fer-
tilizer from 300 to 450 pounds per acre gave a further significant
increase in yield of lupine. Phosphate gave a significant increase
in yield of lupine for all 8 years, potash for 4 years.
Oat yields with various rates of fertilizer are given in Table
12. Complete fertilizer significantly increased the yield of oats
for grain for 8 years out of 10. Rates of nitrogen increased
oat yields for 2 years, phosphate gave a significant increase
in yield for 8 years and potash for the last 7 years.










TABLE 11.-BLUE LUPINE YIELDS FROM 1948 THROUGH 1957 WITH VARIOUS ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Green Weight-1000 Pounds per Acre *

I I I i
P20z KO 1948 1949 1950 1952 1953 1954 1955 1956 Average

21 15 6.7 2.8 11.2 7.5 2.5 4.1 7.3 9.6 6.5
42 30 11.2 7.1 17.0 10.9 4.9 9.5 14.7 18.6 11.7
63 45 12.4 7.0 19.1 12.5 5.9 13.5 17.3 20.3 13.5
21 45 7.4 4.8 12.8 8.7 3.2 5.9 10.8 12.3 8.2
42 45 12.3 6.9 17.3 12.0 4.7 9.7 17.1 17.4 12.2
63 45 12.4 7.0 19.1 12.5 5.9 13.5 17.3 20.3 13.5
63 15 11.6 6.6 17.0 11.7 4.9 9.4 14.3 19.4 11.9
63 30 11.7 8.4 18.4 11.7 5.3 10.1 17.5 18.2 12.7
63 45 12.4 7.0 19.1 12.5 5.9 13.5 17.3 20.3 13.5

L.S.D. (.05) 2.2 2.5 2.0 2.1 .8 2.8 1.5 3.0
L.S.D. (.01) 3.0 3.4 2.7 2.8 1.1 3.9 2.0 4.2

SSevere freezes in February completely killed the lupine in 1951 and 1957.












TABLE 12.-OAT YIELDS FROM 1948 THROUGH 1957 WITH VARIOUS ANNUAL RATES OF FERTILIZER APPLICATION.

Pounds per Acre Yield of Oats for Grain-Bushels per Acre

I I I I I I I I I
N P205 KO 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average

21 25 20 15 11 8 48 52 52 23 18 17 21 27
42 50 40 25 15 23 73 63 58 28 22 20 31 36
63 75 60 26 14 26 89 62 61 30 27 26 39 40
21 75 60 26 19 26 71 62 54 32 27 21 33 37
42 75 60 25 16 22 72 62 53 28 29 22 33 36
63 75 60 26 14 26 89 62 61 30 27 26 39 40
63 25 60 17 10 16 60 61 45 20 17 15 20 28
63 50 60 24 14 21 72 65 49 27 22 20 30 34
63 75 60 26 14 26 89 62 61 30 27 26 39 40
63 75 20 20 10 22 67 47 41 17 17 18 25 28
63 75 40 20 15 23 81 59 43 28 22 19 33 34
63 75 60 26 14 26 89 62 61 30 27 26 39 40
______ ____________________________ ___________ _I _____ ______________________
L.S.D. (.05) 7 N.S. 10 13 8 11 7 4 3 9
L.S.D. (.01) 10 14 17 11 14 10 5 4 12








Effect of Fertilizers, Lime and Green Manure 23

LIME EXPERIMENT
The lime experiment consisted of 4 treatments arranged
in randomized block design with 4 replications on a 3-year rota-
tion. Rates of applications were 0, 2,000, 4,000, and 6,000 pounds
of dolomitic lime per acre, applied in 1947, reapplied as dolomite
in 1954 and reapplied as calcic lime in 1957. The 3-year rotation
used was as follows: Peanuts, lupine under, corn, oats for grain,
soybeans under, oats under. The experiment was laid out in
triplicate, similar to the fertility experiment, so that all crops
received the treatments every year.
At planting time corn and oats for grain received 500 pounds
per acre of 2-10-8 fertilizer. For the first 5 years corn was top-
dressed with 32 pounds of nitrogen from Uramon and oats with
32 pounds from nitrate of soda. Corn for the last 6 years and
oats for grain for the last 5 years were top-dressed with 32
pounds per acre of nitrogen from ammonium nitrate. Oats
turned under received annual applications of 500 pounds of 2-10-8
per acre. Peanuts were fertilized with 400 pounds of 2-10-4 per
acre the first 3 years and 500 pounds per acre of 2-10-8 fertilizer
the last 8 years. Blue lupine, Crotalaria spectabilis and soy-
beans received annually 300 pounds per acre of 0-14-10 fertilizer.
Yields of corn with various rates of lime are shown in
Table 13. Lime at 2,000 pounds per acre gave a 3-bushel per
acre average increase in yield of corn over no lime. Higher
rates gave only 1 bushel additional. The response to lime in-
creased after the second application of lime in 1954, which sug-
gested that the soil calcium had decreased to a point where it
limited corn yields or that previous applications were too low.
These results indicate that lime is probably needed for optimum
corn growth on Norfolk loamy fine sand.
Peanut yield responses to lime are shown in Table 14. One
ton of lime gave a significant increase in yield of peanuts for 3
years and a slight increase for 4 years. Peanuts were dusted
with 3 or 4 20-pound applications of elemental sufur-DDT mix-
ture per acre each year to control leaf spot, army worms and
velvet bean caterpillars. The sulfur made the soil more acid.
Twenty-seven months after 1 ton of lime had been applied, the
soil had reached about the same pH level as before liming (Table
15). This would indicate that lime should be applied every 3
years to maintain the initial reaction in the soil, but less fre-
quently if no sulfur is applied.










TABLE 13.-YIELDS OF CORN FROM 1947 THROUGH 1957 WITH VARIOUS RATES OF LIME.
Lime *
Pounds ____Yield of Corn-Bushels per Acre
per Acre 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average

0 39 41 78 98 69 36 76 43 50 67 61 60
2,000 41 45 82 101 74 38 82 43 50 72 69 63
4,000 42 42 82 105 69 39 81 43 50 70 70 63
6,000 40 44 85 103 71 38 83 40 54 71 71 64

L.S.D. (.05) N.S. 4 6 4 5 N.S. 6 N.S. N.S. N.S. 5
L.S.D. (.01) N.S. N.S. N.S. N.S. N.S.__ I 8__
The amount indicated was applied in 1947 as dolomite and reapplied in 1954 as dolomite and in 1957 as high calcic lime.


TABLE 14.-YIELD OF PEANUTS FROM 1947 THROUGH 1957 WITH VARIOUS RATES OF LIME.
Lime *
Pounds Yield of Unshelled Peanuts-Pounds per Acre
per Acre 1947 1948 1949 1950 1951 1952 1953 1954 I 1955 1956 I 1957 Average

0 1,630 1,760 1,100 1,650 1,910 1,370 1,450 1,580 1,560 1,360 910 1,480
2,000 1,890 1,660 1,130 1,630 2,350 1,780 1,550 1,910 1,450 1,250 1,030 1,600
4,000 1,910 1,530 1,000 1,610 2,120 1,290 1,560 1,970 1,590 1,250 1,080 1,540
6,000 1,990 1,520 1,100 1,640 2,020 1,520 1,370 1,930 1,680 1,290 1,140 1,560

L.S.D. (.05) 210 160 N.S. N.S. N.S. 330 N.S. 280 N.S. N.S. 190
L.S.D. (.01) 300 N.S. I I N.S. I N.S.| N.S. _
The amount indicated was applied in 1947 as dolomite and reapplied in 1954 as dolomite and in 1957 as high calcic lime.








Effect of Fertilizers, Lime and Green Manure 25

TABLE 15.-THE PH OF THE SOIL OF PEANUT PLOTS WITH
VARIOUS RATES OF LIME.

Dolomitic Lime pH Before pH of Soil Months After Treatment
Pounds per Acre Treatment with Lime
1947 15 21 27
0 5.5 5.6 5.5 5.1
2,000 5.6 6.1 6.0 5.7
4,000 5.6 6.5 6.6 6.1
6,000 5.5 6.7 6.9 6.5


Crotalaria and soybean yield response to lime appears in
Table 16. In 1947 lime produced a significant increase in yield
of crotalaria. This was probably associated with inoculation.
Bacteria reproduced better on the limed soil. However, after
a year the unlimed soils had sufficient numbers so that lime did
not affect yields. Lime gave a significant increase in the forage
yield of soybeans for 3 years. The yield increase followed the
second application of lime in 1954 and meant that possibly the
first application was not sufficient for optimum growth.
Yields of oats with various rates of lime are shown in Table
17. Lime gave a significant increase in yield of oats for 2 years,
and a slight increase for 5 years.
The effects of lime on lupine yields are presented in Table 18.
Lime gave a significant increase in yield of lupine for only 1
year out of 8. However, for many of the years where no re-
sponse was obtained, yields were low due to factors other than
treatments.
Yields of oats for grain with various rates of lime are shown
in Table 19. There was no significant positive response to lime
for any of the years, and 1 year the response was negative.

EFFECT OF LIME ON ROTATIONS
In 1954 and 1957 half of each plot in the rotation experiment
was treated with 1 ton per acre of calcic lime, making a random-
ized split plot design with 4 replications.
The effect of lime on yield of corn grown in various rotations
is shown in Table 20. For 3 years out of 4 lime gave a signifi-
cant increase in yield of corn in a continuous crop and a 2-year
rotation plot. Figure 9 shows the effect of lime on growth of
corn in 1957. Lime increased yield of corn an average of 16









TABLE 16.-YIELDS OF CROTALARIA AND SOYBEANS FROM 1947 THROUGH 1957 WITH VARIOUS RATES OF LIME.

Lime* Green Weight of Crotalaria- Green Weight of Soybeans-
Pounds per -1,000 Pounds per Acre 1,000 Pounds per Acre
Acre 1947 1948 1949 1950 1951 Ave. 1952 1953 1954 1955 1956 1957 I Ave.

0 18.2 34.6 25.5 15.3 13.6 21.4 13.2 20.4 12.6 14.4 14.4 15.1 15.0 1
2,000 24.4 30.6 25.5 14.5 14.0 21.8 13.1 23.4 14.7 15.3 22.4 19.0 18.0
4,000 22.8 31.4 24.3 12.3 14.7 21.1 14.6 24.2 14.1 15.2 22.4 19.1 18.3
6,000 22.6 32.1 24.4 14.0 13.6 21.3 14.5 24.3 14.7 16.7 24.0 20.4 19.1

L.S.D. (.05) 3.6 N.S. N.S. N.S. N.S. N.S. N.S. N.S. 1.4 2.1 3.7
L.S.D. (.01) 5.2 __N.S. 3.0 N.S.
The amount indicated was applied in 1947 as dolomite and reapplied in 1954 as dolomite and in 1957 as high calcic lime.

TABLE 17.-YIELDS OF OATS FOR GREEN MANURE FROM 1947 THROUGH 1957 WITH VARIOUS RATES OF LIME.
Lime n
Pounds per __Green Weight of Oats-1,000 Pounds per Acre 2.
Acre 1948 1949 1950 1951** 1952 1953 1954 1955 1956 1957 Average

0 7.6 16.0 14.2 9.1 7.0 9.3 8.2 18.4 10.6 11.2
2,000 9.1 18.9 15.5 11.6 9.2 10.3 8.0 21.9 9.5 12.7
4,000 8.7 15.7 17.0 11.5 11.9 9.3 8.2 24.0 9.9 12.9

6,000 9.7 14.2 13.9 11.0 7.9 8.7 8.0 I 21.8 11.8 11.9

L. S. D. (.05) 1.5 N.S. 2.5 N.S. N.S. N.S. N.S. I N.S. N.S.
L. S. D. (.01) N.S. I N.S._
The amount indicated was applied in 1947 as dolomite and reapplied in 1954 as dolomite and in 1957 as high calcic lime.
** A severe freeze in February killed the top growth, making harvest impractical.






TABLE 18.-YIELDS OF LUPINE FROM 1948 THROUGH 1957 WITH VARIOUS RATES OF LIME.
Lime *
Pounds per Green Weight-1,000 Pounds per Acre**
Acre 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average

0 9.6 7.8 17.4 10.2 4.3 9.9 16.1 18.9 11.8 s
(O
2,000 12.1 7.3 18.5 12.7 4.7 12.0 17.4 18.8 12.9

4,000 12.5 8.1 20.9 13.9 4.2 13.1 16.5 18.1 13.4

6,000 11.6 5.7 19.2 11.7 4.6 13.4 16.6 19.1 12.7

L. S. D. (.05) 1.7 N.S. N.S. N.S. N.S. N.S. I N.S. N.S.
L. S. D. (.01) 2.4 __ __ _
SThe amount indicated was applied in 1947 as dolomite and reapplied in 1954 as dolomite and in 1957 as high calcic lime.
"** Severe freezes destroyed the lupine crop in 1951 and 1957.


TABLE 19.-YIELDS OF OATS FOR GRAIN WITH VARIOUS RATES OF LIME.

Lime* Dry Oats for Grain-Bushels per Acre
Pounds per Acre 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Average qZ

0 21 17 39 79 64 50 26 24 22 39 38

2,000 25 17 30 77 59 50 27 24 22 32 36

4,000 23 18 28 88 53 46 32 20 30 31 37

6,000 23 25 24 76 46 45 28 21 30 26 34

L. S. D. (.05) N.S. N.S. N.S. N.S. 12 N.S. N.S. N.S. | N.S. N.S.
L. S. D. (.01) N.S.
The amount indicated was applied in 1947 as dolomite and reapplied in 1954 as dolomite and in 1957 as high calcic lime. --1









TABLE 20.-EFFECT OF LIME* ON THE YIELDS OF CORN, 1954 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATIONS.

SYield of Corn-Bushels per Acre
SAve. Increase
Rotation 1954 1955 1956 Ave. Increase 1957 from
INo No No No from No Lime for
SLime Lime LLim e me Lime Lime Lime Lime Lime Lime Lime 1957
Continuous corn: I
Corn only ................... 35 31 50 46 48 48 44 42 2 64 57 7
With soybeans, oats** 38 33 51 46 53 47 47 42 5 61 56 5
With soybeans .......... 38 39 51 50 57 53 49 48 1 67 67 0
With lupine ** .......... 40 39 52 51 65 62 52 51 1 64 61 3
Average ..................... 38 36 51 48 56 52 48 46 2 64 60 4
2-year:
Peanuts, lupine**
Corn .----------. ... 42 40 53 51 61 54 52 49 3 68 48 20
Peanuts, lupine**
Corn with
velvet beans .......... 40 41 52 51 60 54 51 49 2 66 50 16
Peanuts, lupine**
Corn with soybeans** 42 40 52 50 58 49 51 46 5 64 51 13
Average ...................... 41 40 52 51 60 52 51 48 3 66 | 50 16
3-year:
Peanuts, lupine**
Corn, lupine** ............ 40 40 53 54 65 62 52 52 0 64 50 14
Corn, oats** ............... 42 42 53 53 58 58 51 51 0 74 62 12
Peanuts, lupine**
Corn, oats for grain
Soybeans**, oats** 41 39 54 56 64 63 53 52 1 69 48 21
Average ...................... 41 40 53 54 | 62 61 52 52 0 69 53 16
Significance lime N.S. ** **
Lime x treatment.. N.S. N.S. N.S. **
One ton of calcic lime applied in 1954 and reapplied in 1957. ** Crops plowed under as green manure, t One and two asterisks signify significance at 5% and 1%
level. N.S. signifies non-significance.








Effect of Fertilizers, Lime and Green Manure 29

bushels per acre in the rotations and 4 bushels per acre for con-
tinuous cropping. Since the vines, roots and nuts were removed
from the land, rotations with harvested peanuts depleted the
soil of lime more rapidly than continuous corn where only the
ears of corn were removed.
Peanut yield response to lime for the various rotations are
presented in Table 21. The first year calcic lime increased the
yield of peanuts 250 to 580 pounds per acre. The second year
after lime was applied, the yield of peanuts was increased 50 to
380 pounds per acre, and the third year 80 to 420 pounds per
acre. This is evidence the 1 ton of calcic lime is not sufficient to
bring the calcium level to an optimum level. The response to
lime is much larger the first year than the second or third year
after application. In 1957 a second ton of lime was applied,
which increased peanut yields 180 to 323 pounds per acre.

Fig. 9.-Corn in a 3-year rotation of peanuts, lupine, corn, oats for
grain, soybeans, oats. Left: Corn in 1957 which received 2 tons of calcic
lime, with 1 ton applied in 1954 and the second in 1957. Right: Corn with
no lime.




























0









TABLE 21.-EFFECT OF LIME* ON THE YIELDS OF PEANUTS FROM 1954 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATIONS.

Peanut Yields-Pounds per Acre Ave.
I I Increase
Rotation 1954 1955 1 1956 1957 Average from
SNo No No No No Lime
Lime Lime Lime Lime Lime Lime Lime Lime Lime Lime me e
Continuous peanuts: 3
Peanuts only .......... 730 260 930 640 620 540 810 490 770 480 290
With lupine** ........ 530 280 980 660 730 560 580 350 710 460 240
Average .................. 630 270 955 650 680 550 700 420 740 470 270
2-year: -.
Peanuts, lupine** .. 1,050 760 1,430 1,110 1,010 840 1,170 950 1,170 920 250
Corn
Peanuts, lupine** .. 1,160 720 1,460 1,300 1,320 900 1,000 780 1,240 930 310
Corn with
velvet beans
Peanuts, lupine** .. 1,300 720 1,540 1,160 1,140 950 1,160 980 1,280 950 330
Corn with soybeans _
Average ................. 1,170 730 1,480 1,190 1,160 900 1,110 900 1,230 930 300
3-year:
Peanuts, lupine** .. 1,370 1,080 1,660 1,590 1,230 920 1,110 900 1,340 1,120 220
Corn, lupine**
Corn, oats**
Peanuts, lupine** .. 1,470 1,130 1,910 1,860 1,280 1,100 1,040 820 1,430 1,230 200
Corn, oats for grain
Soybeans,** oats**___
Average .................. 1,420 1,100 1,790 1,720 1,260 1,010 1,080 860 1,380 1,180 210

Significance Lime .... ** ** ** **
One ton of calcic lime applied in 1954 and reapplied in 1957.
** Crops plowed under as green manure.
t Two asterisks signify significance at the 1% level of probability.







TABLE 22.-EFFECT OF LIME* ON YIELD OF SOYBEANS, 1954 THROUGH 1957, WHEN PLANTED IN ROTATION.

S__Green Weight of Soybeans-1,000 Pounds per Acre Ave.
II I Increase h
Rotation 1954 1955 1956 1957 Average Infromee
I No No i No | No INo I Lime
Lime Lime Lime Lime Lime Lime | Lime Lime Lime Lime

3-year:
Peanuts, lupine** .. 12.7 11.2 13.9 11.6 18.9 11.1 15.2 13.7 15.2 11.9 3.3
Corn, oats for grain
Soybeans**, oats**
-------------- -_ _ _ _ __-__ _ _
Significance lime N.S.
years N.S.

One ton of high calcic lime was applied in 1954 and again in 1957.
** Crops plowed under as green manure.


TABLE 23.-EFFECT OF LIME* ON YIELD OF PEANUTS IN THE HARVESTING VERSUS HOGGING-OFF PEANUT EXPERIMENT.

Peanuts-Pounds per Acre Average
SIncrease
Continuous Peanuts 1954 1955 1956 i Average from
No No No No Lime
Lime Lime Lime Lime Lime Lime Lime Lime

Harvested, lupines** ............................. 996 644 1,249 1,159 1,117 782 1,121 862 259
Hogged-off ............................................. 808 724 1,354 1,268 1,146 943 1,103 978 125

One ton of high caleic lime was applied in 1954.
** Crops plowed under as green manure.








32 Florida Agricultural Experiment Stations

The yield response to lime for soybeans grown in a 3-year
rotation are shown in Table 22. Lime gave a slight increase
for 3 years and a large increase for 1956 (7,800 pounds per acre)
in the forage yields of soybeans.
The effect of lime on yield of hogged-off peanuts is presented
in Table 23. Lime increased the 3-year average yield of harvest-
ed peanuts 259 pounds per acre, but increased the yield of hogged-
off peanuts only 125 pounds per acre. When peanuts are har-
vested, a large amount of calcium is removed from the soil each
year in the vines and roots. When they are hogged-off, only

TABLE 24.-EFFECT OF LIME* ON THE YIELDS OF LUPINE, 1955 AND 1956,
WHEN PLANTED IN VARIOUS ROTATIONS.

Green Weight-1,000 Pounds per Acre
Rotation
1955 1956
Lime No Lime Lime No Lime

Continuous peanuts
with lupine** ............. .....-- 5.3 3.4 7.2 4.7


Continuous corn with lupine** 11.6 9.6 12.0 12.9


2-year:
Peanuts, lupine**, Corn ........ 11.5 9.6 11.4 9.0
Peanuts, lupine,**
Corn with velvet beans .......... 10.4 8.3 11.2 8.2
Peanuts, lupine,**
Corn with soybeans ................ 12.4 9.2 10.0 8.6

3-year:
Peanuts, lupine** ..................- 10.0 11.0 10.3 11.7
Corn, lupine** .-..-..-..--........ 10.6 10.7 10.1 11.1
Corn, oats**
Peanuts, lupine** .................... 10.3 10.2 13.6 11.0
Corn, oats for grain
Soybeans, oats**


Average -.......--- ......- .- ......-- 10.3 9.0 10.7 9.7


Significance of lime ............. *- **
lime x treatment ..--....----... **

*One ton of calcic lime was applied in 1954.
** Crops plowed under as green manure.
t One and 2 asterisks signify significance at 5% and 1% level of probability, re-
spectively.








Effect of Fertilizers, Lime and Green Manure 33

the nuts are removed and consequently less calcium. This prob-
ably accounts for the higher response to calcium on the harvested
peanuts.
Lupine yields showing the effect of lime are presented in
Table 24. Lime gave a highly significant increase in the yield
of lupine on both the continuous peanut plots and the 2-year
rotations, but little or none on the continuous corn plots and
3-year rotations.
The response of oats to lime in various rotations is shown in
Table 25. Lime gave a small but usually not significant increase
in the yield of oats for green manure and a 4-bushel increase
in yield of oats for grain.

HARVESTING VERSUS HOGGING-OFF PEANUTS
This experiment was a comparison of 2 systems of manage-
ment with continuous peanuts. One system was hogging-off;
the other was harvesting both nuts and hay, and following with
lupine. Peanuts were fertilized with 400 pounds of 2-10-4 fer-
tilizer the first 3 years and 500 pounds per acre of 2-10-8 ferti-
lizer the last 7 years. Yields of the hogged-off peanut plots were
determined by harvesting the peanuts from small measured
areas from each plot before they were hogged-off. Lupine re-
ceived 300 pounds of 0-14-10 per acre for each of the 10 years.
Yields of peanuts are shown in Table 26. Continuous pea-
nuts harvested and followed by lupine for green manure made
about the same 10-year average yield as continuous peanuts
hogged-off.
Hogging-off peanuts removes from the soil only the gain
in the hogs. Many of the plant nutrients are returned. In har-
vesting peanuts the vines, part of the roots and the nuts are
taken off, which reduces the soil fertility more than hogging-
off does. In this experiment the lupine plus the fertilizer it
received apparently compensated for this difference, so the yields
were the same.

APPLYING FERTILIZER TO PRESENT VERSUS
PRECEDING CROP
The experiment contained 4 treatments arranged in a ran-
domized block design with 4 replications on a 3-year rotation.
The same 3-year rotation was used as in the lime and fertility
experiment. Similar to these experiments, all crops received








Effect of Fertilizers, Lime and Green Manure 33

the nuts are removed and consequently less calcium. This prob-
ably accounts for the higher response to calcium on the harvested
peanuts.
Lupine yields showing the effect of lime are presented in
Table 24. Lime gave a highly significant increase in the yield
of lupine on both the continuous peanut plots and the 2-year
rotations, but little or none on the continuous corn plots and
3-year rotations.
The response of oats to lime in various rotations is shown in
Table 25. Lime gave a small but usually not significant increase
in the yield of oats for green manure and a 4-bushel increase
in yield of oats for grain.

HARVESTING VERSUS HOGGING-OFF PEANUTS
This experiment was a comparison of 2 systems of manage-
ment with continuous peanuts. One system was hogging-off;
the other was harvesting both nuts and hay, and following with
lupine. Peanuts were fertilized with 400 pounds of 2-10-4 fer-
tilizer the first 3 years and 500 pounds per acre of 2-10-8 ferti-
lizer the last 7 years. Yields of the hogged-off peanut plots were
determined by harvesting the peanuts from small measured
areas from each plot before they were hogged-off. Lupine re-
ceived 300 pounds of 0-14-10 per acre for each of the 10 years.
Yields of peanuts are shown in Table 26. Continuous pea-
nuts harvested and followed by lupine for green manure made
about the same 10-year average yield as continuous peanuts
hogged-off.
Hogging-off peanuts removes from the soil only the gain
in the hogs. Many of the plant nutrients are returned. In har-
vesting peanuts the vines, part of the roots and the nuts are
taken off, which reduces the soil fertility more than hogging-
off does. In this experiment the lupine plus the fertilizer it
received apparently compensated for this difference, so the yields
were the same.

APPLYING FERTILIZER TO PRESENT VERSUS
PRECEDING CROP
The experiment contained 4 treatments arranged in a ran-
domized block design with 4 replications on a 3-year rotation.
The same 3-year rotation was used as in the lime and fertility
experiment. Similar to these experiments, all crops received










TABLE 25.-EFFECT OF LIME* ON THE YIELD OF OATS, 1955 THROUGH 1957, WHEN PLANTED IN VARIOUS ROTATINOS.

Green Weight of Oats-1,000 Pounds per Acre I Ave.
Rotation I Increase
1955 1956 I 1957 ] Average from
_Lime No Lime Lime No Lime Lime No Lime I Lime No Lime Lime

Continuous corn I
with soybeans,**
oats** .............. ...... 4.2 2.7 5.6 5.2 5.3 4.0 5.0 4.0 1.0

I 3.
3-year: ]
Peanuts, lupine**
Corn, lupine**
Corn, oats** .........- 4.2 3.9 9.9 7.5 5.6 5.6 6.6 5.7 .9
Peanuts, lupine**
Corn, oats for grain
Soybeans,** oats** ...... 8.2 8.0 15.2 14.8 7.5 6.8 10.3 9.9 .4


Significance (lime)t .... N.S. N.S. *

Oats for Grain-Bushels per Acre

Peanuts, lupine**
Corn, oats for grain .... 22 19 Lost Lost 37 33 30 26 4
Soybeans,** oats**

*One ton of calcic lime was applied in 1954 and again in 1957.
** Crops plowed under as preen manure.
t N.S. means non-significant and 1 asterisk indicates significance at 5% level.
















TABLE 26.-YIELDS OF CONTINUOUS PEANUTS IN THE "HOGGED-OFF" AND HARVESTED PEANUT EXPERIMENT.

Continuous P s Peanuts-Pounds per Acre
Continuous Peanuts
1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 Ave.


Hogged-off* ............... 2,550 1,160 860 1,870 2,030 1,130 1,180 770 1,310 1,040 1,390
Harvested ...................... 2,550 1,200 960 i 1,370 2,040 1,190 1,090 820 1,200 950 1,340


L. S. D. (.05) .............. N.S. N.S. N.S. 162 N.S. N.S. N.S. N.S. N.S. N.S. N.S.
L. S. D. (.01) ............297

Yields taken from four rows 10 feet lorr.







36 Florida Agricultural Experiment Stations

these treatments every year. Applying fertilizer directly to the
crop was compared to applying fertilizer at the same rate to
the preceding crop, except that the 10 and 42 pounds of nitrogen
was applied directly to the corn and no nitrogen was applied to
the preceding crop of lupines. In 1957 2 tons per acre of calcic
lime were applied to all plots. The rates of fertilizer used are
given in Table 27, along with yield data. These data show the
following:
For 3 years the yield of corn was significantly higher when
the fertilizer was applied to the corn instead of the preceding
crop. For the other 4 years the yield was slightly higher when
the fertilizer was applied to the preceding. The 7-year average
yield was 4 to 5 bushels higher when the fertilizer was applied
to the corn crop instead of the preceding crop.
Yield of oats for grain for 6 years was significantly higher
when the fertilizer was applied directly to the oats instead of
the preceding crop.
For the 6 years the average forage yield of soybeans was
about the same whether the fertilizer was applied to the soy-
beans or the preceding crop. Since oats responded to fertilizer,
it would be better to apply the fertilizer to the oats in the ro-
tation.
For 5 years out of 6 years the forage yield of oats was sig-
nificantly higher when the fertilizer was applied to the oats
instead of the preceding soybean crop. These results indicate
that it would be best to apply the fertilizer to the oats instead
of the soybeans in the rotation.
For the 7 years the average yield of peanuts was about the
same, regardless of whether the fertilizer was applied to the
preceding crop or to the peanut crop. Since the preceding crop,
oats, responded to fertilizer, it would be better to apply the
fertilizer to the other crops in the rotation and let the peanuts
use the residual fertilizer.
For 2 years out of 5 the yield of lupine was significantly
higher when the fertilizer was applied to the lupine instead of
the peanut crop. For the remaining 3 years yields were consist-
antly higher for direct fertilization. These results indicate that
it would be better to apply the fertilizer to the lupine instead of
the peanuts in the 3-year rotation.
In a 3-year rotation consisting of corn, oats for grain; soy-
beans, oats for green manure; peanuts, lupines for green manure;
corn, oats (for grain or green manure) and lupine should be







TABLE 27.-ANNUAL YIELDS OF CROPS IN ROTATION AS AFFECTED BY DIRECT OR INDIRECT FERTILIZATION.

Pounds per acre Fertilized 1951 1952 1953 1954 1955 1956 1957* Ave.
N P P205 I K O Method Crop I _
Corn Yields in Bushels per Acre

10 50 40 Directly Corn 65 32 70 38 50 60 66 54
10 50 40 Preceding crop Lupine"** 64 33 58 41 50 50 51 49
42 50 40 Directly Corn 66 30 71 39 50 62 74 56
42 50 40 Preceding crop Lupine** 67 34 56 38 54 55 60 52

L. S. D. (.05) N.S. N.S. 6 N.S. N.S. 7 10
L. S. D. (.01) 9 10 14
____________ _____[____. .-- ---I--- ____
Oat Yields in Bushels per Acre

10 50 40 Directly Oats -59 52 34 26 20 26 36 1
10 50 40 Preceding crop Corn -49 39 20 23 16 18 28
42 50 40 Directly Oats -- 67 57 37 30 24 22 39
42 50 40 Preceding crop Corn 51 38 19 23 19 18 28 S
_____ ------------------------_____ 1 ----___ ----__-__--___ _____----____
L. S. D. (.05) 10 12 5 4 5 5
L. S. D. (.01) 15 18 7 6 8 N.S.

Green Yields of Soybeans, 1,000 Pounds per Acre

0 50 40 Directly Soybeans 24.1 20.0 10.9 14.8 9.2 16.1 15.8
42 50 40 Preceding crop Oats -21.8 24.4 11.4 13.6 9.1 16.2 16.1

Significance I N.S. N.S. N.S. N.S. N.S.
____________ ______________________ -I 1___ -.____________________









00
TABLE 27-(Continued)

Pounds per acre Fertilized 1951 1952 1953 1954 1955 1956 1957* Ave.
N I P205 K20 I Method I Crop __ __
Green Yields of Oats, 1,000 Pounds per Acre _
II i
10 50 40 Directly Oats 9.4 6.5 8.8 8.8 19.2 7.0 9.9
0 50 40 Preceding crop Soybeans 3.4 3.8 5.4 7.7 13.9 2.4 6.1

Significance ** ** ** N.S. **

Peanut Yields, Pounds per Acre of Nuts

10 50 40 Directly Peanuts 2,210 1,760 | 2,040 1,460 2,160 1,670 1,230 1,790
10 50 40 Preceding crop Oats 2,060 1,690 | 1,930 1,660 2,220 1,510 1,270 1,760

Significance N.S. IN.S. N.S. I N.S. N.S.

Green Yields of Lupines, 1,000 Pounds per Acre
II I
0 50 40 Directly Lupines -7.3 2.7 6.9 11.2 11.9 8.0
101 50 40 Preceding crop Peanuts .8 2.6 5.0 7.1 9.5 5.6

Significance ** N.S. N.S. N.S. C-

In 1957 lupines were killed by a severe freeze.
** The 10 pounds and the 42 pounds of nitrogen were applied directly to the corn and no nitrogen was applied to the preceding crop of lupines.
t N.S. indicates not significant. One and two asterisks refer to significance at the 5 and 1 percent level of probability respectively.







Effect of Fertilizers, Lime and Green Manure 39

fertilized directly. Soybeans or peanuts yield about the same
if their fertilizer is applied to the preceding crop rather than
directly to them.

CHEMICAL CONTENT OF SOILS AND PLANTS
Soil and plant samples were taken from all treatments in the
fertility experiment and selected treatments in the rotation and
lime experiments in 1949 and 1950. The object was to compare
the concentrations of some of the important nutrients in the soil
with those in the plants and to correlate both these sets of data
with crop yield.
In succeeding years, to 1957, soil samples only were selected
from the rotation, fertilizer and lime experiment for the pur-
pose of correlating with crop yield.
Soil samples were extracted with ammonium acetate buffered
at pH 4.7. Potassium, calcium and magnesium were determined
using the Beckman B flame photometer in 1949 and 1950, for
plants and soil samples (4). The remaining years, potassium and
calcium were determined on the Beckman DU and magnesium
colorimetrically using sodium polyacrylate to stabilize the color
(5). Phosphorus was extracted in 1949 and 1950 with Truog's
extractant, .002N HSO, (10) and the remaining years with
Bray's strong solution, .03N NH4F in 0.1 N HC1 using 10 parts
extractant to one part soil (1).
Treatments were sampled from the rotation, fertilizer and
lime experiments in 1949 and 1950. In 1949 the plots sampled
were planted in peanuts and in 1950 in corn. The treatments
used are shown in Tables 28 and 29.
Samples were taken from 2 replicates of the treatments listed
in Table 28. Peanuts were sampled 9 times at 2-week intervals
to a depth of 6 inches from May 5, to September 1, 1949. Plant
samples were taken August 12 and September 12 from the same
plots (6).
Analytical data are reported in Table 28. Since time of sam-
pling had no significant effect, dates and replicates are averaged.
Hence each figure for the soils analyses represents 18 samples
and each figure for the plant analyses represents 4 samples.
Yield data are added for comparison. Increasing the rate of
phosphate and potash increased the phosphorus and potassium
contents of the soil and peanut plants, but did not increase the
yield of peanuts. When the rate of dolomitic lime was increased,
phosphorus, calcium and magnesium contents of the soil and









TABLE 28.-CHEMICAL ANALYSES OF SOIL AND PLANTS FROM PEANUT PLOTS AND YIELD OF PEANUTS FOR 1949. 0

Fertilizer I ISoil Analyses Plant Analyses Peanuts
I Dolomite pH 1 Pounds
Pounds per Acre I Pounds per Acre Percent per Acre
N | PO25 K2 0 PO2s K20 Ca Mg P IK Ca Mg

12 20 24 0 5.2 9 15 460 7 0.17 2.6 1.00 0.49 1,290 .
12 40 24 0 5.1 17 162 520 8 0.20 2.5 0.95 0.52 1,270
12 60 24 0 5.1 29 142 590 9 0.22 2.1 0.95 0.50 1,150
12 60 8 0 5 .1 34 111 640 9 0.22 1.4 1.24 0.63 1,260
12 60 16 0 5.1 30 122 550 6 0.21 2.0 1.01 0.53 1,190
12 60 24 0 5 .1 29 142 590 9 0.22 2.1 0.95 0.50 1,150
8 40 16 0 5.2 23 128 470 12 0.22 2.2 0.87 0.56 1,100
8 40 16 2,000 5.8 24 125 740 81 0.22 1.8 0.79 0.69 1,130
8 40 16 4,000 6.1 41 140 1,030 139 0.25 2.0 0.79 0.73 1,000
8 40 16 6,000 6.7 51 133 1,270 227 0.30 2.0 0.93 0.85 1,100 t

Rotation
Continuous:
Peanuts only ........................... 5.0 18 79 350 1 0.22 0.9 0.74 0.58 820
2-year:
Peanuts, lupine* .....--........ 5.0 18 96 370 1 0.20 1.5 0.87 0.51 1,080 .
corn I
3-year: I
Peanuts, lupine* ....................... 5.2 21 131 510 13 0.21 2.1 0.87 0.56 1,020
corn, oats for grain
crotalaria*, oats*

Plowed under as green manure.








Effect of Fertilizers, Lime and Green Manure 41

phosphorus and magnesium contents of the peanut plants were
increased, but yield was not affected.
Potassium and calcium contents of the soil and plants and
yield of peanuts were lower where peanuts were grown con-
tinuously than where peanuts were grown every second year
in a rotation. Potassium, calcium and magnesium contents of
the soil and potassium content of the plants were lower where
peanuts were grown every second year than where peanuts were
grown every third year in rotation. Results indicate that the
levels of potassium, calcium and magnesium in the soil and plant
are indirectly correlated with the number of times peanuts are
grown in a given period.
Surface soil samples were taken from 2 replicates of the
treatments listed in Table 29 on March 28, May 18, June 26, July
13 and August 31, 1950, for chemical analyses. Plant samples
were taken from 2 replicates of the same treatments May 18,
June 26, July 13 and August 31. Since the data for time of sam-
pling were not significant, replications and dates were averaged.
Hence, the figure in Table 29 represent 10 samples for the soils
data and 8 for the plant data.
As the rate of phosphate was increased, phosphorus and cal-
cium contents of soil and corn plants and yield of corn increased.
When the rate of potash was increased, potassium contents of
soil and plants and yield of corn increased. As the potassium
content of corn plants increased, calcium content decreased.
When the rate of dolomitic lime was increased, phosphorus, cal-
cium and magnesium content of the soil and phosphorus and
magnesium content of corn plants and yield of corn increased.
Calcium and magnesium content of soil and plants and yield
of corn were lower in continuous corn than in corn in rotation.
The phosphorus content of soil growing continuous corn was
higher than that of soil growing corn in rotation. Phosphorus
content of the plant was the reverse. This discrepancy may be
correlated with the method of determine available phosphorus.
The phosphorus extracted with .002 N H2SO4 is primarily inor-
ganic phosphorus. In the continuous corn plots the phosphorus
was probably in the inorganic form, but in the rotation plots
where cover crops had been grown over winter it is possible that
considerable phosphorus was still in the organic form during
sampling time and this phosphorus was available to the plants
even though not extractable by the reagent used.










TABLE 29.-CHEMICAL ANALYSES OF SOILS AND PLANTS FROM CORN PLOTS AND YIELD OF CORN FOR 1950.

I .Yield
Soil Analyses Corn
Pounds per Acre P Plant Analyses-Percent Bus.
Pounds per Acre pH Pounds per Acre per
N P2O KO I Dolomite P,05 K20O Ca I Mg P K Ca Mg Acre

63 25 60 0 5.3 10 93 450 29 0.18 2.2 0.91 0.32 88
63 50 60 0 5.2 19 91 560 27 0.20 1.9 1.04 0.32 95 .
63 75 60 0 5.2 26 87 790 28 0.22 1.8 1.07 0.40 100

63 75 20 0 5.2 28 80 640 26 0.20 1.3 1.31 0.52 90
63 75 40 0 5.3 32 95 620 27 0.20 1.5 1.19 0.42 98
63 75 60 0 5.2 26 87 790 28 0.22 1.8 1.07 0.40 100

42 50 40 0 5.4 32 80 670 38 0.20 1.6 1.04 0.46 98 9
42 50 40 2,000 5.8 36 79 900 61 0.22 1.5 0.97 0.60 101
42 50 40 4,000 6.0 41 87 1,240 109 0.23 1.5 1.02 0.68 105
42 50 40 6,000 6.6 72 79 1,470 180 0.24 1.4 0.99 0.76 103


Rotation
Continuous: I
Corn ....-...--.-....- .... 5.5 31 70 500 25 0.14 1.5 0.58 0.35 58

2-year:
Peanuts, lupine'* ........... 5.2 20 72 520 26 0.18 1.4 0.86 0.49 84
Corn
3-year:
Peanuts, lupine* ....................- 5.2 27 80 620 27 0.18 1.4 0.98 0.46 93
Corn, oats for grain
Crotalaria*, oats*

Plowed under as green manure.








Effect of Fertilizers, Lime and Green Manure 43

In another experiment 2 soil tests showed that Norfolk loamy
fine sand fixed a very large amount of inorganic phosphorus,
which was partly made available later. This may explain why
corn shows phosphorus deficiency symptoms early in the spring
and then later recovers. Because this soil has the capacity to
fix large amounts of phosphorus, most crops need more phos-
phorus than nitrogen or potassium fertilizers.
In addition to the above mentioned soil-plant-yield correlation
in 1949 and 1950, the rotation experiment was sampled approxi-
mately every 2 years for soil-yield correlations. Data from the
1957 soil samples are recorded in Table 30. The pH, calcium,
potassium, magnesium and phosphorus were generally lower on
the continuous peanut plots than on the continuous corn plots.
Since both crops received the same amount of fertilizer, 500
pounds per acre of 2-10-8 fertilizer annually, it is evident that
peanuts deplete the soil of fertility faster than corn. The 2-
year rotation plots, while not as low in fertility as the continuous
peanut plots, were significantly lower than the continuous corn
plots. The quantity of phosphorus was about the same in the
3-year rotation plots as in the continuous corn plots. All the
other nutrients were slightly lower in the 3-year rotation plots
than in the continuous corn plots, but higher than in the 2-year
rotation plots.
These results indicate that continuous corn well fertilized did
not deplete the soil any more than a 3-year rotation. This ex-
plains why the yield of corn continued to be high, even after 10
years of continuous cropping to corn (Table 1). Since corn yields
for the rotations continued to be slightly higher than for con-
tinuous corn treatments, even though chemical analyses of soil
showed fertility in general somewhat lower on the rotation than
continuous corn treatment, possibly some other undetermined
factor-microbiological or chemical-was limiting yields when
corn was grown continuously.
Soil samples were taken from 4 replications of the fertilizer
experiment for chemical analysis, usually every 2 years as in
the rotation experiment. Results from 1955 through 1957 are
given in Table 31. Data from the surface samples show that
there was an increase in phosphate, potash and calcium in the
soil where these elements were applied, but a decrease in mag-
nesium. Lime did not increase the calcium level as much as
might have been expected possibly because of the coarseness of
the limestone. From 1947 to 1955 when no lime was applied

Pritchett, W. L. Unpublished data. Soils Dept., Univ. of Fla. 1949.









TABLE 30.-CHEMICAL ANALYSES OF SOILS IN 1957 AS AFFECTED BY CROP ROTATIONS AND LIME.*

Pounds per Acre
pH
Rotation __Ca K20 _Mg Bray P.O0
No INo 1 No No No
SLime | Lime Ave. Lime Lime Ave. Lime Lime Ave. Lime Lime Ave. Lime Lime Ave.

Continuous peanuts:
Peanuts only ............... 5.0 4.7 4.8 75 35 55 45 37 41 15 12 14 240 253 246
With lupine** ............ 5.0 4.6 4.8 85 24 55 35 29 37 18 12 15 256 272 264

Average ..................... .0 4.6 4.8 80 30 55 40 33 39 16 12 14 248 262 255

Continuous corn:
Corn only ......... ...--- 5.8 5.2 5.5 241 121 181 130 100 115 61 25 43 290 244 267
With soybeans, oats**- 5.6 5.2 5.4 275 115 195 146 135 140 70 16 43 256 341 348
With soybeans** .......... 5.6 5.3 5.4 249 127 185 132 131 132 73 29 51 304 320 312
With lupines** .............. 5.7 5.1 5.4 192 100 146 119 101 110 65 28 46 240 229 234

Average .......................... 5.7 5.2 5.4 239 116 j 177 132 117 124 67 24 46 298 284 290

2-year:
Peanuts, lupine** ......... 5.4 4.7 5.0 147 55 101 47 53 50 52 11 32 211 269 240
Corn ...............-............ 5.3 4.9 5.1 117 48 83 63 62 62 36 10 23 240 230 235
Peanuts, lupine** .......... 5.2 4.7 4.9 129 46 87 56 45 50 32 12 22 278 206 242
Corn and velvet beans 5.5 4.8 5.2 135 39 87 79 67 73 37 9 23 226 183 204
Peanuts, lupine** ....... 5.2 4.8 5.0 141 57 99 44 47 46 35 21 28 256 225 240
Corn, soybeans** ......... 5.4 4.9 5.2 145 39 92 63 56 60 49 7 28 246 267 256

Average .......................... 5.3 4.8 5.1 136 47 92 59 55 57 40 12 26 243 230 236









TABLE 30-(Continued)

Pounds per Acre
pH I
Rotation I Ca KO Mg Bray P20O
No No No No No
Lime Lime Ave. Lime ie A Lm Lime Ave. Lime Lime Ave. Lime Lime e Ave. Lime Lime Ave.

3-year:
Peanuts, lupine** .......... 5.3 4.7 5.0 148 59 103 73 51 62 49 16 32 254 247 250
Corn, lupine** ........... 5.5 5.1 5.3 224 87 155 84 83 84 60 12 36 270 284 277
Corn, oats** ................. 5.4 4.9 5.1 157 67 112 87 74 80 47 20 34 266 302 284
Peanuts, lupine** ......... 5.2 4.6 4.9 148 43 95 76 61 68 41 12 26 292 315 304
Corn, oats for grain .... 5.3 4.7 5.0 215 104 159 91 87 89 54 20 37 272 278 275
Soybeans**, oats** ...... 5.1 4.7 4.9 153 56 105 83 72 78 30 10 20 363 403 383


Average ................ 5.3 4.8 5.0 174 69 122 821 71 77 47 15 31 286 305 296


Grand Average .............. 5.4 4.9 5.1 165 68 116 81 72 76 46 16 31 270 271 270


L.S.D. (.05) treatment .17 55 26 11 68
L.S.D. (.01) treatment .23 74 35 14 89
Limet ............................. ** ** ** I ** N.S.
Lime x treatment ........ N.S. N.S. N.S. ** N.S.
One ton calci_ lie applied in 1954. Cros lowed under as green manure. t Two asterisks indicate significance at 1% level of probability.
One ton calcic lime applied in 1954. ** Crops plowed under as green manure. t Two asterisks indicate significance at 1% level of probability.









TABLE 31.-CHEMICAL ANALYSES OF PREFERTILIZATION SAMPLES FROM FERTILITY EXPERIMENT.

Average of 4 Replications
Fertilizers Depth
Pounds of 1955 1956 1957 Ave. '55, '56, '57
per Acre Sample I P
pH Pounds per Acre p Pounds per Acre pH Pounds per Acre pH Pounds per Acre
N I P2O5 | K20 I KO | Ca [ Mg P205"* KO Ca jMg IP2Os* j K20 I Ca (Mg PWO*l | K20 Ca Mg |P20O*
II I
21 25 20 0- 6" 4.9 38 64 61 237 5.0 68 104 10 268 5.1 50 90 32 320 5.0 52 86 38 238
6-12" 5.2 38 104 61 52 5.0 43 70 7 42 4.8 11 52 12 50 5.0 31 75 26 48
12-18" 5.4 47 200 141 26 5.2 40 198 22 24 5.0 21 152 18 38 5.2 36 183 22 29
18-24" 5.7 31 285 209 28 5.6 28 312 54 23 5.4 18 324 42 34 5.6 26 307 102 28
24-30" 5.6 29 179 341 32 5.5 21 252 82 23 5.3 18 348 66 28 5.4 23 260 163 28

42 50 40 0- 6" 4.8 49 51 43 412 5.0 86 105 8 467 5.1 101 121 31 513 4.9 79 92 27 464
6-12" 5.0 44 29 44 41 5.0 48 78 7 62 4.6 13 90 12 42 4.9 35 66 21 48
12-18" 5.2 65 139 116 27 5.0 60 180 17 32 4.8 28 204 12 42 5.0 51 174 48 34
18-24" 5.8 37 315 196 28 5.5 41 353 48 24 5.1 26 366 18 28 5.5 35 345 90 28
24-30" 5.4 31 179 453 33 5.3 28 332 96 26 5.2 18 420 40 42 5.3 26 310 196 34

63 75 60 0- 6" 4.8 83 112 30 761 5.0 90 150 8 680 4.8 125 103 27 885 4.8 99 122 22 775
6-12" 5.0 52 19 55 78 5.0 72 42 8 99 4.5 18 62 12 156 4.8 47 41 25 111
12-18" 4.9 102 109 69 26 5.0 96 134 12 34 4.6 42 62 18 38 4.8 80 102 33 33
18-24" 5.4 72 357 127 37 5.4 57 256 20 23 4.9 115 272 24 34 5.3 81 295 57 31
24-30" 5.6 27 320 317 39 5.4 32 437 68 26 5.4 27 486 36 39 5.4 29 414 140 35

21 75 60 0-6" 4.8 38 120 52 720 5.1 109 185 8 759 5.0 120 120 33 834 5.0 89 142 28 771
42 75 60 0-6" 4.8 37 78 44 690 5.1 107 153 10 745 5.0 135 121 29 912 5.0 93 117 28 782
63 75 60 0-6" 4.8 68 112 64 761 5.0 90 150 10 680 4.8 125 103 27 885 4.8 94 122 34 775

Average 4.8 48 103 53 724 5.0 102 163 9 728 4.9 127 115 30 877 4.9 92 127 30 776
_________________________ _____ I__-_____________ __________ -__-__ I ________ __









TABLE 31-(Continued)

Average of 4 Replications
Fertilizers Depth
Pounds of 1955 1956 1957 Ave. '55, '56, '57
per Acre Sample I I ]
pH i Pounds per Acre I pH Pounds per Acre pI Pounds per Acre pH Pounds per Acre
N PO | KO K,O Ca Mg |PO,*| KsO| Ca |Mg |PO,*j I K.O Ca |Mg PMO*| I K2O I Ca Mg PzO6*

63 25 60 0-6" 4.7 72 32 50 243 5.0 108 64 10 277 4.9 166 90 30 342 4.8 115 62 30 287
63 50 60 0-6" 4.8 36 54 38 478 5.0 107 90 21 488 4.9 119 102 38 572 4.9 87 82 32 513
63 75 60 0-6" 4.8 68 112 66 761 5.0 90 150 10 680 4.8 125 103 27 885 4.8 94 122 34 775

Average 4.7 59 66 51 494 5.0 102 101 14 484 4.8 137 98 32 600 4.8 99 89 32 525

63 75 20 0-6" 4.7 46 80 52 727 5.0 56 126 20 749 4.9 51 112 40 846 4.8 51 106 37 774
63 75 40 0-6" 4.7 50 102 62 692 5.0 73 124 19 715 4.9 80 112 28 807 4.8 68 113 36 738
63 75 60 0-6" 4.8 68 112 64 761 5.0 90 150 10 680 4.8 125 103 27 885 4.8 94 122 34 775

Average 4.7 55 98 59 727 5.0 73 133 16 715 4.8 85 109 32 846 4.8 71 114 36 762

AVERAGE** 4.8 45 80 50 572 5.0 89 110 12 583 4.9 107 107 32 692 4.9 83 104 31 611

Extracted with .03 N NH,F in .1 N HC1.
** Averages are of the 0-6" samples.








48 Florida Agricultural Experiment Stations

to the fertilizer experiment, the calcium content decreased from
636 to 80 pounds per acre and the pH from 5.6 to 4.8. For this
period there was an increase of phosphate and potash in the soil.
These results indicate that soil in a 3-year rotation should re-
ceive 1 ton of lime per acre approximately every 5 years to main-
tain a calcium level high enough for good growth of legume crops.
In a study of the soil profile it was found that the calcium
and magnesium decreased in the surface soil and some moved
into the subsoil. Some of the potassium tended to move into
the layer below 12 inches, but the largest concentration was in
the top 6 inches. Most of the phosphorus remained in the top
6 inches of soil, with a slight movement into the second 6-inch
layer. The latter is probably due to plowing deeper than 6
inches.
Soils data from 4 replications of the lime experiment for
1956, and 1957 are present in Table 32. These and unreported
data indicate that 1 ton of lime applied approximately every 5
years would be required to maintain the original pH of 5.6.
There was an increase in the phosphate, potash and calcium con-
tent of the limed plots, but in the plots without lime there was
a loss of calcium. Two tons of lime applied approximately every
5 years would be required to maintain a pH of 6.3 in Norfolk
loamy fine sand.
The effect of dolomitic lime on pH and the movement of phos-
phorus, calcium, magnesium and potassium in the soil is shown
in Table 33. With 1 ton of lime applied to the soil there was very
little movement of calcium into the second 6-inch layer of soil.
With 2 tons of lime applied to the soil there was some movement
of calcium into the 6- to 12-inch layer, but no movement into the
12- to 18-inch layer of soil. When 3 tons of lime were applied
to the soil, calcium moved into the 12- to 18-inch layer of soil,
but there was no movement of calcium below 18 inches.
There was a large movement of magnesium from the sur-
face layer into the 18- to 24-inch and 24- to 30-inch layers. As
most of the magnesium had moved into the 24- to 30-inch layer,
deeper samples of the soil profile no doubt would have shown that
large quantities of magnesium had moved into the layers of soil
below 30 inches, and possibly a large quantity had been lost from
the soil in the drainage water. Since magnesium moved down
the soil profile much faster than calcium, magnesium deficiency
was found on many more soils than calcium deficiency, and es-
pecially on old land that had never received dolomitic lime.








Effect of Fertilizers, Lime and Green Manure 49

When 1 ton of lime was added, the potassium tended to re-
main in the top 6 inches of soil, with only a slight movement
into the 6- to 12-inch layer of soil. As more lime was applied,
there was a little more movement of potassium into the 6- to
12-inch and 12- to 18-inch layers of soil, but no movement into
the 18- to 24-inch and 24- to 30-inch layers of soil.

TABLE 32.-CHEMICAL ANALYSES OF PREFERTILIZATION
SOIL SAMPLES FROM LIME EXPERIMENT.

1956 1957
Lime*
Pounds I Pounds per Acre Pounds per Acre
per Acre Bray I I Bray
pH K2O Ca IMg PO, IpH KsO Ca I Mg PO.,
0 5.4 82 150 30 450 4.8 101 137 67 550
2,000 6.2 92 410 101 560 5.5 110 290 109 570
4,000 6.3 93 580 134 490 5.9 126 370 140 560
6,000 1 6.6 114 | 770 i 188 460 6.2 130 480 221 520

Received the indicated rates of dolomitic lime in 1947 and again in 1954. An addi-
tional application of high calcic lime was made in 1957 after sampling.

There was only a slight movement of phosphorus into the
6- to 12-inch layer of soil and no movement below that depth.
These results indicated that there was only a small loss of
calcium and potassium, a large loss of magnesium and no loss
of phosphorus from the surface soil.
The organic matter of the soil as determined by the Walkley
Method (11) for the first, fifth and tenth years of the rotation
experiment are shown in Table 34. The loss of the first 4 years
on plot and rotation basis is compared with that for the last 6
years. For the first 4 years the loss in organic matter was high-
ly significant for all the plots. For the last 6 years there was a
slight loss for the continuous peanut plots and a slight gain
for the continuous corn plots. There was practically no change
in the 2-year rotation plots, but the 3-year rotation plots gained
about twice as much organic matter as the continuous corn plots.
These results indicate that the 3-year rotation was the best sys-
tem for maintaining the organic matter in the soil. They also
showed that the poorest system of soil management was con-
tinuous peanuts with or without lupine. Since the lupine after
continuous peanuts was almost a complete failure, it added prac-
tically no organic matter to the soil.
The organic matter content of soil from plots of the fertilizer
experiment is shown in Table 35. For the first 4 years there was








50 Florida Agricultural Experiment Stations

TABLE 33.-EFFECT OF LIME ON PH AND THE MOVEMENT OF PHOSPHORUS,
CALCIUM, MAGNESIUM AND POTASSIUM IN THE SOIL.

Depth in _Rates of Lime (Pounds per Acre)*
Inches 0 1 2,000 4,000 1 6,000
pH

0-6 5.0 5.8 6.0 6.5
6-12 5.0 5.5 5.7 6.5
12-18 5.0 5.2 5.3 6.0
18-24 5.3 5.4 5.7 5.9
24-30 5.4 5.5 5.5 5.8

Bray P** pounds per acre Ps20

0-6 593 462 494 472
6-12 68 38 44 34
12-18 14 14 20 16
18-24 14 14 14 14
24-30 14 24 14 14

Total 703 552 582 550

Ca pounds per acre

0-6 68 318 560 848
6-12 28 42 112 324
12-18 50 64 50 228
18-24 292 262 280 228
24-30 312 288 254 200

Total 750 974 1,256 1,828

Mg pounds per acre

0-6 16 30 104 184
6-12 5 15 46 111
12-18 12 28 40 118
18-24 30 76 87 208
24-30 71 109 183 256

Total _134 258 460 877

K pounds per acre of KsO

0-6 146 130 105 102
6-12 28 32 60 80
12-18 68 70 80 62
18-24 56 51 47 14
24-30 13 15 12 8

Total 311 298 304 266
The amounts indicated were applied as dolomitic lime in 1947 and reapplied in 1954
as dolomitic lime. The soil samples were taken in the spring of 1957 prior to another applica-
tion of high calcic lime.
** Phosphorus was extracted with .03 N NHaF in .1 N HC1.








Effect of Fertilizers, Lime and Green Manure 51


TABLE 34.-EFFECT OF CROPPING ON ORGANIC MATTER.

Difference** from
Rotation 1947 1951 1957 1947 1951
to to
1951 1957

Continuous peanuts
Peanuts only ... ....... 2.1 1.4 1.2 -0.7 -0.2
With lupine* ...........--.. 2.1 1.3 1.2 -0.8 -0.1


Average cont. peanuts.. -0.8 -0.1


Continuous corn
Corn only .....................- 2.1 1.5 1.4 -0.6 -0.1
With crotalaria*, oats* 2.0 1.6 1.7 -0.4 0.1
With crotalaria* .....--.... 2.1 1.5 1.6 -0.6 0.1
With lupine* ................ 2.0 1.6 1.7 -0.4 0.1


Average cont. corn ... -0.5 0.1


2-year rotations
Peanuts, lupine* ........... 2.1 1.5 1.5 -0.6 0.0
Corn ............................... 2.0 1.4 1.5 0.6 0.1

Peanuts lupine* ............ 2.1 1.5 1.5 -0.6 0.0
Corn with velvet beans 2.0 1.4 1.5 -0.6 0.1

Peanuts, lupine* .......... 2.1 1.5 1.5 -0.6 0.0
Corn with crotalaria* .. 2.1 1.6 1.5 -0.5 -0.1


Ave. 2-year rotation ...... -0.6 0.0


3-year rotation
Peanuts, lupine* ......... 1.9 1.5 1.4 -0.4 -0.1
Corn, lupine* ..........-..... 2.1 1.3 1.7 -0.8 0.4
Corn, oats* ................... 2.2 1.5 1.6 -0.7 0.1

Peanuts, lupine* ........... 2.0 1.7 1.6 -0.3 -0.1
Corn, oats for grain .... 2.1 1.5 1.8 -0.6 0.3
Crotalaria*, oats* ........ 2.2 1.7 1.8 -0.5 0.1


Ave. 3-year ............. .... | 0.6 0.1


L. S. D. (.05) .....-..- .......... N.S. 0.2 0.2
L. S. D. (.01) ............. .. 0.3 0.3

Crops plowed under as green manure.
** Minus sign indicates a decrease in organic matter while no sign indicates an increase.








52 Florida Agricultural Experiment Stations

a large loss of organic matter. For the next 6 years the results
ranged from no loss to a slight gain for low rates of fertilizer,
but considerable gain of organic matter for high rates of ferti-
lizer. High rates of fertilizer produced high yields of vegeta-
tion which, when plowed under, added more organic matter to
the soil.

TABLE 35.-ORGANIC MATTER AS AFFECTED BY RATES OF
FERTILIZER ELEMENTS.

Percent
Pounds per Acre Organic Matter Difference* from
S1947 1951
_to to
N P,,O I K20O 1947 1951 1957 1951 1957

21 25 20 2.5 1.8 1.8 -0.7 0.0
42 50 40 2.1 1.8 2.0 -0.3 0.2
63 75 60 2.4 1.8 2.0 -0.6 0.2
21 75 60 2.2 2.0 1.9 -0.2 -0.1
42 75 60 2.3 1.8 2.0 -0.5 0.2
63 75 60 2.4 1.8 2.0 -0.6 0.2
63 25 60 2.4 1.8 1.9 -0.6 0.1
63 50 60 2.5 1.8 1.9 -0.7 0.1
63 75 160 2.4 1.8 2.0 -0.6 0.2
63 75 20 2.4 1.9 1.9 -0.5 0.0
63 I 75 40 2.4 1.8 2.0 -0.6 0.2
63 75 60 2.4 1.8 2.0 -0.6 0.2

Average ............................. 0.5 0.2

Minus sign indicates loss of organic matter.

The moisture equivalents (2) of the soils from the plots of
the rotation and continuous crop experiment for the first, fourth
and tenth years of the test are given in Table 36. The gain or
loss is compared for 4 and 6 years consecutively. For the first
4 years there was a large decrease in the moisture equivalent
for all systems of cropping. For the next 6 years the loss was
less and in the case of continuous corn there was a gain.
The moisture equivalents of the soils from the plots of the
fertilizer experiment for the first, fourth and tenth years are
presented in Table 37. There was a large loss in moisture equiv-
alent for the first 4 years, but little or no loss for the next 6
years.
The effect of rotation systems and fertilizer on percent
moisture equivalent is correlated with the loss of organic matter









Effect of Fertilizers, Lime and Green Manure 53


TABLE 36.-EFFECT OF CROPPING ON MOISTURE EQUIVALENT IN PERCENT.

Difference from**
Rotation 1947 1951 1957 1947 1951 1947
to to to
1951 1957 1957

Continuous peanuts
Peanuts only ...... 8.6 6.4 6.0 -2.2 -0.4
With lupine* ...... 8.6 6.1 5.8 -2.5 -0.3

Average
cont. peanuts .. -2.4 -0.4 -2.8

Continuous corn
Corn only ......... -- 8.6 6.5 6.5 i -2.1 0.0
With crotalaria*,
oats ............... 8.6 6.6 7.0 2.0 0.4
oats ----------- 8. .14
With crotalaria* 8.6 6.5 6.8 -2.1 0.3
With lupine* ...-. 8.6 6.6 6.9 -2.0 0.3

Average
cont. corn ........ -2.0 0.2 -1.8

2-year rotations
Peanuts, lupine* 8.6 6.6 6.0 -2.0 -0.6
Corn ................ 8.6 6.1 6.3 2.5 0.2

Peanuts, lupine* 8.6 6.4 5.9 -2.2 -0.5
Corn with
velvet beans .... 8.6 6.0 6.3 -2.6 0.3

Peanuts, lupine* 8.6 6.5 6.2 -2.1 -0.3
Corn with
crotalaria* ..... 8.6 6.4 6.1 -2.2 -0.3

Ave. 2-year
rotation ....-...-... I_ -2.3 -0.2 -2.5

3-year rotations ....
Peanuts, lupine*.- 8.6 6.6 5.7 -2.0 -0.9
Corn, lupine* -.... 8.6 6.1 6.6 -2.5 0.5
Corn, oats* ........ 8.6 6.6 6.5 -2.0 -0.1

Peanuts, lupine* 8.6 6.7 6.1 -1.9 -0.6
Corn, oats
for grain ..-..... 8.6 6.3 7.0 -2.3 0.7
Crotalaria*, oats* 8.6 6.9 6.6 -1.7 -0.3

Ave. 3-year
rotation ........... -2.1 --0.1 -2.2

L. S. D. 5% ........ N.S. 0.2 0.5
L. S. D. 1% .... .. 0.3 0.7

Crops plowed under as green manure.
"** Negative sign indicates decrease in moisture equivalent and no sign indicates an
increase.








54 Florida Agricultural Experiment Stations

(Tables 34 and 35). This is probably because variations in mois-
ture equivalent would be due to organic matter. The other
major factor contributing to moisture equivalent was clay.
However, it was not affected by treatment.
It is clear from these data that even with good soil manage-
ment it was not possible to maintain the organic matter content
of virgin Norfolk loamy fine sand. The loss of organic matter,
however, was largest during the first 4 years and the extent
it declined was related to the cropping system and fertilizer
practice. The luss was largest for continuous peanuts and less
for 3-year rotations and continuous corn. Two-year rotations
fell between these 2 systems.

TABLE 37.-MOISTURE EQUIVALENT AS AFFECTED BY RATES OF FERTILIZER
ELEMENTS.

Percent
Pounds per Acre Moisture equivalent Difference* from
1947 1951
to to
N P20 KO 1 1947 1 1951 | 1957 1951 1957
21 25 20 8.1 6.5 6.3 -1.6 -0.2
42 50 40 8.0 6.4 6.4 -1.6 0.0
63 75 60 8.1 6.5 6.6 -1.6 0.1
21 75 60 8.0 6.6 6.4 -1.4 -0.2
42 75 60 7.7 6.4 6.5 -1.3 0.1
63 75 60 8.1 6.5 6.6 -1.6 0.1
63 25 60 7.9 6.5 6.3 -1.4 -0.2
63 50 60 7.7 6.2 6.5 -1.5 0.3
63 75 60 8.1 6.5 6.6 -1.6 0.1
63 75 20 7.6 6.5 6.5 -1.1 0.0
63 75 40 8.0 6.5 6.4 -1.5 -0.1
63 75 60 8.1 6.5 6.6 -1.6 0.1

Average .................. I... _ __ -1.5 0.0
Minus sign indicates decrease in moisture equivalent, no sign indicates increase: the
values for the highest level are repeated but not used more than once in the average.

When high rates of fertilizer were applied to 3-year rota-
tions, organic matter loss was less than when the fertility level
was low. Since most soils in Florida are very low in clay content,
the humus or decomposed organic matter constitutes the main
part of the cation-exchange capacity of these soils (9). Since
cation-exchange is a valuable soil property from the standpoint
of moisture and fertilizer retention, it is important that prac-
tices be used that will keep organic matter at a high level.










TABLE 38.-NEMATODE POPULATION AS AFFECTED BY ROTATIONS AND LIME AFTER 10 YEARS. .

Nematode Count by Species per 150 ml. of Moist Soil
Cricon-
Rotation Trichodorus emoides Pratylenchus Xiphinema Others Total
christiei spp. brachyurus spp. Average
L | UL L UL L UL L UL L UL L UL

Continuous
Peanuts only ... 3 0 6 3 8 5 2 0 269 13 288 21 104
Continuous
Corn only ..-.... 73 19 1 1 7 10 5 73 444 171 530 274 402


2-year:
Peanuts, lupine* 8 6 2 2 35 41 0 5 568 205 613 259 436
Corn ..............-- .... 59 19 6 7 6 4 5 26 192 129 268 185 226


3-year:
Corn, oats* ...... 216 49 3 5 6 7 7 33 517 149 749 243 496
Peanuts, lupine* 15 4 2 1 23 6 22 107 700 120 762 238 500
Corn, lupine* .... 100 55 15 1 11 0 0 0 313 80 439 136 288


Total ......---- 474 152 35 20 96 73 41 244 3,003 867 3,649 1,356 2,502

Crops plowed down as green manure.


Wn










CA






TABLE 39.-MONTHLY AND ANNUAL RAINFALL IN INCHES AT THE EXPERIMENTAL SITES. -

Month 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 Ave.


January ...... 6.2 5.0 1.9 0.7 1.6 1.5 3.0 2.4 4.0 4.9 0.8 2.9 0
February ........... 3.3 1.0 4.9 1.2 1.6 8.3 5.0 2.3 1.8 5.2 1.6 3.3
March ...................... 6.1 13.6 5.5 5.4 10.3 5.2 1.7 2.3 0.9 2.7 4.5 5.3
April ......-......-......... 9.2 14.2 7.6 5.3 2.1 4.1 6.7 2.2 8.3 2.2 4.8 6.1
May .....- ............ 7.8 2.4 1.5 5.2 8.0 2.8 1.6 2.0 2.2 3.7 6.2 3.9
June .......................... 5.9 4.7 6.8 6.4 3.9 3.8 6.9 2.3 1.1 6.8 6.2 5.0
July ........................ 5.0 11.2 8.0 5.8 4.2 2.5 8.3 4.1 11.3 8.2 3.4 6.5
August ............. 4.9 6.6 9.4 4.7 4.8 6.6 1.8 3.2 4.1 1.8 2.4 4.6
September .............. 5.0 6.3 1.4 2.8 3.5 5.8 7.1 3.4 1.3 6.1 15.3 5.3
October .................... 3.7 3.3 5.0 1.5 1.7 .5 1.6 1.5 3.1 4.3 1.3 2.5
November ................ 12.3 4.6 1.9 0.4 6.6 1.2 3.2 2.4 0.8 0.2 5.7 3.6
December ................ 5.6 4.4 3.8 3.5 7.8 2.2 10.1 1.9 2.0 1.9 1.5 4.1


Total ........... 75.0 77.3 57.7 42.9 56.1 44.5 57.0 30.0 40.9 48.0 53.7 53.0
C.







Effect of Fertilizers, Lime and Green Manure 57

NEMATODE STUDIES
Soil samples were collected in May, October and December
1956 from the plots of the rotation experiment and the nema-
tode population was determined by the modified Baermann fun-
nel method (3).
The nematode populations in the rotation and continuous
crop experiment for 1956 are shown in Table 38. The important
plant parasitic nematodes found were Pratylenchus brachyurus,
Trichodorus christiei, Criconemoides spp. and Xiphinema spp.
Only a few specimens of Hoplolaimus were found, although it
had been common in former years. Xiphinema spp. appeared
more numerous than in 1954-1955, while Pratylenchus was con-
siderably less. At the May sampling there were significantly
higher populations of Trichodorus christiei on the corn plots
than on the peanut plots.

SUMMARY AND CONCLUSIONS
A series of experiments was conducted on Norfolk loamy fine
sand over an 11-year period to determine 1) management prac-
tices which result in highest yields of certain cash crops (corn,
peanuts and oats), and 2) effects of these practices on the soil.
Since there are more than 200,000 acres of this soil type in North
Florida, there is a great potential value to the farmers of the
area in sound information on this subject.
The management practices studied were 1) crop rotation,
2) fertilizer level, 3) liming requirement and 4) green manure
crops lupiness, soybeans, Crotalaria spectabilis, and in some
cases oats).

I. Superior Management Practices for Best Yields of Cash Crops
1. Peanuts should be grown in rotation for best yields. A
3-year rotation found satisfactory was: peanuts, lupine
under the first year; corn, oats for grain the second year;
and soybeans followed by oats the third year.
2. Corn yields do not decline as rapidly as peanuts when
grown continuously. Yields of continuous corn can be in-
creased by growing a green manure crop in winter and
plowing it under at least 2 weeks before corn planting
time.
3. Lupines do not grow well after peanuts. However, if they







Effect of Fertilizers, Lime and Green Manure 57

NEMATODE STUDIES
Soil samples were collected in May, October and December
1956 from the plots of the rotation experiment and the nema-
tode population was determined by the modified Baermann fun-
nel method (3).
The nematode populations in the rotation and continuous
crop experiment for 1956 are shown in Table 38. The important
plant parasitic nematodes found were Pratylenchus brachyurus,
Trichodorus christiei, Criconemoides spp. and Xiphinema spp.
Only a few specimens of Hoplolaimus were found, although it
had been common in former years. Xiphinema spp. appeared
more numerous than in 1954-1955, while Pratylenchus was con-
siderably less. At the May sampling there were significantly
higher populations of Trichodorus christiei on the corn plots
than on the peanut plots.

SUMMARY AND CONCLUSIONS
A series of experiments was conducted on Norfolk loamy fine
sand over an 11-year period to determine 1) management prac-
tices which result in highest yields of certain cash crops (corn,
peanuts and oats), and 2) effects of these practices on the soil.
Since there are more than 200,000 acres of this soil type in North
Florida, there is a great potential value to the farmers of the
area in sound information on this subject.
The management practices studied were 1) crop rotation,
2) fertilizer level, 3) liming requirement and 4) green manure
crops lupiness, soybeans, Crotalaria spectabilis, and in some
cases oats).

I. Superior Management Practices for Best Yields of Cash Crops
1. Peanuts should be grown in rotation for best yields. A
3-year rotation found satisfactory was: peanuts, lupine
under the first year; corn, oats for grain the second year;
and soybeans followed by oats the third year.
2. Corn yields do not decline as rapidly as peanuts when
grown continuously. Yields of continuous corn can be in-
creased by growing a green manure crop in winter and
plowing it under at least 2 weeks before corn planting
time.
3. Lupines do not grow well after peanuts. However, if they







58 Florida Agricultural Experiment Stations
are grown after peanuts they should not be grown more
than once in 3 years.
4. When peanuts or soybeans are grown in a 3-year rotation
such as that referred to in 1 above they make about the
same yields if part of or all of the fertilizer is applied to
the preceding crop (oats for green manure and oats for
grain) than when fertilized directly.
5. Corn and oats grown in a 3-year rotation should be fer-
tilized directly, since this soil does not retain fertilizer
in adequate amounts to produce good yields of these crops.
6. Corn, peanuts, soybeans, oats and lupine need supple-
mental fertilizer. When grown in the 3-year rotation
mentioned in 1 above, a good rate of fertilization for corn
and oats is 600 pounds per acre of 4-12-12 at planting
with 60 to 100 pounds per acre of nitrogen as a side-dress-
ing and a top-dressing. The nitrogen may be reduced to
half the rate where the crop follows a legume cover crop
making good growth. Soybeans, crotalaria and lupine
should receive 450 pounds per acre of 0-14-14 and peanuts
200 pounds per acre of 0-14-14.
7. When peanuts are hogged-off and followed by native cov-
er, yields decline about the same as continuous peanuts
harvested and followed by lupine plowed under for green
manure. This indicates that continuous peanuts, even
when they are hogged-off, still have a detrimental effect
on the soil.
8. Lime is required to produce good yields. After 11 years
adequate lime increased peanut yields 250 to 580 pounds
per acre, corn yields up to 26 bushels and soybean yields
as much as 7 bushels.

II. Effect of Cash Cropping and Management Practices on the
Soil
1. Norfolk loamy fine sand had approximately 400 pounds
per acre of exchangeable calcium in the virgin state.
When cropped for 7 years to a 3-year rotation, the level
was reduced to approximately 100 pounds per acre. At
this point a ton of lime improved yields of peanuts, corn
and soybeans, but did not raise the pH above 5.7. It
would require approximately a ton of lime every 5 years
to maintain the pH of soil cropped to a 3-year rotation







Effect of Fertilizers, Lime and Green Manure 59

with corn, peanuts, oats and soybeans. Unless the pH
is maintained at or near pH 6.0, yields of general farm
crops are usually reduced due to the lack of lime.
2. The soil organic matter and moisture equivalent decreased
when a virgin soil was cropped, regardless of the soil man-
agement practices. The decrease was larger when continu-
ous peanuts were grown and the vines and nuts removed
than for continuous corn where only the ears of corn were
harvested. Growing corn and peanuts in rotation gave
values between those obtained for continuous peanuts
and continuous corn. For rotational cropping the de-
crease was less, depending on the magnitude of the ratio
of corn to peanuts in the rotation.
The levels of exchangeable calcium, potassium and
magnesium were correlated with the organic matter. In
sandy soils of this type where the clay content is low,
organic matter is important, since it is the major source
of the exchange capacity. The detrimental effect of pea-
nuts on the level of soil organic matter as compared to
corn is probably part of the reason why yields decrease
more rapidly when peanuts are grown continuously than
when corn is grown continuously. Organic matter in the
high fertilized corn plots was higher than in the low fer-
tilized plots.
3. Applied phosphorus remained in the surface 6" layer of
soil. Calcium and potassium moved down the profile, but
not below the root zone of most crops.
4. Magnesium moved down the profile to 30 inches and deep-
er and probably part of it leached out of the soil. This
means that on old land which has never been limed before,
dolomitic instead of calcic lime should be applied. After
an application of dolomite, calcic lime may be used alter-
nately.
ACKNOWLEDGMENTS
The authors are indebted to Dr. F. B. Smith for his constructive criti-
cism through the experiment; Dr. G. M. Volk for his assistance in the
initial planning of the experiment; Dr. J. R. Neller and Dr. Nathan Gam-
mon, Jr., for their participation on the project in 1947 and 1948; Dr. W. L.
Pritchett for his assistance in 1949; Mr. R. W. Prevatt for chemical analyses
of 1949 and 1950 samples; and to Mr. W. H. Thames, Jr., for nematode
studies. Professor W. D. Hanson was consulted relative to the statistical
analysis. Criticisms and suggestions by the late Mr. J. D. Warner are
gratefully acknowledged.








60 Florida Agricultural Experiment Stations

LITERATURE CITED

1. BRAY, R. H., and L. T. DURTZ. Determination of total organic, and
available forms of phosphorus on soils. Soil Sci. 59: 39. 1945.
2. BRIGGS, L. J., and J. W. McLANE. The moisture equivalent of soils.
USDA Bur. of Soils, Bul. 45. 1907.
3. CHRISTIE, J. R., and V. G. PERRY. Removing nematodes from the soil.
Proc. of Helminthology Soc. of Wash. 18: (2): 106-108. 1951.
4. GAMMON, NATHAN, JR. Determination of total potassium and sodium
in sandy soils by flame photometer. Soil Sci. 71: 211. 1951.
5. MEHLICH, A. Improvements in colometric magnesium and ammonium
methods with polyacrylate. Jour. A. O. A. C., 39: 518-523. 1956.
6. PREVATT, R. W. Unpublished Master's Thesis. Soils Department Univ.
of Fla. 1951.
7. ROBERTSON, W. K., C. E. HUTTON, and W. D. HANSON. Crop response
to different soil fertility levels in a 5 by 5 by 2 factorial experi-
ment: II Peanuts. Soil Sci. Soc. of Amer. Proc. 20: 537-543. 1956.
8. THOMPSON, L. G., JR., and W. K. ROBERTSON. Effect of rotations, fer-
tilizers, lime and green manure crops on crop yield and on soil
fertility. Fla. Agr. Exp. Sta. Bul. 522. 1953.
9. THOMPSON, L. G., JR., and F. B. SMITH. Organic matter in Florida
soils. Fla. Agr. Exp. Sta. Bul. 433. 1947.
10. TRUOG, E. The determination of readily available phosphorus of soils.
Jour. Am. Soc. Agron. 22: 974-982. 1930.
11. WALKLEY, ALLEN. A critical examination of a rapid method for deter-
mining organic carbon in soils. Effect of variations in digestion
conditions, and of inorganic constituents. Soil Sci. 63: 251-264.
1947.





University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs