Calcium in the nutrient solution around the fruit (top) made the difference.
Calcium and Boron Effects on
HENRY C. HARRIS
BULLETIN 723 (TECHNICAL) APRIL 1968
Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
J. W. Sites, Dean for Research
Introduction---------- ------------------- 3
Literature Review ........ .------- ---------- 3
Calcium --------------------------------------- 3
Boron ...---------...-----------------------. 5
Methods ...--------.....--------..--------. 8
Nutrient Solution ....------.-.---------. --------.--. ---.--- 8
Soil ....--- -----------........... 8
Results and Discussion --------- --.-------- ----------------9 9
Solution Studies with Calcium and Boron 9
Soil Studies with Boron ---.....--...- -----------------------. 12
Summary ---...---.... -----.----- ------ ----- 15
Literature Cited ..... ---.-----------------.. -------- 18
Photographs showing that calcium in the nutrient solution around the
young fruit was necessary for normal seed development (1,3). Solution
contained 80 ppm of calcium.
Calcium and Boron Effects on Florida Peanuts
Henry C. Harris'
It has been known for years that calcium, especially in the
fruiting zone, is of great importance in the production of the
peanut, Arachis hypogaea L. The value of boron for quality
yields has become evident more recently. These nutrients in-
fluence foliage, flower, root and fruit yields, as well as the
characteristics of the plant, and the quality of the seed produced.
The purpose of this bulletin is to review the more important
Florida findings with both nutrient solutions and soil experi-
ments and to present additional results with both boron and
calcium but especially compares the effect of boron on different
varieties of peanuts.
The primary effect of calcium deficiency has been to decrease
the yield and quality of fruit, but the deficiency has not notice-
ably affected the foliage. However, the results have varied with
different conditions. Withholding calcium from the nutrient so-
lution from the middle of the growing season to harvest time
(1, 3)2 appreciably decreased shoot, flower, root and fruit pro-
duction. Where calcium was not applied to the fruiting zone, the
amount of fruit produced was negligible (see photographs on
cover), apparently due to inadequate movement of calcium (2)
through the "peg" for normal seed development. Thus an ex-
ternal supply of available calcium in the nutrient solution around
the growing fruit is necessary for good seed production.
An application of calcium in pot cultures to soils low in this
element increased the yield and quality of the peanuts produced
(4, 7 and Figure 1), as well as affected the growth of foliage.
Without the addition of calcium the pods usually had a low shell-
ing percentage of seed (or conversely, a high percentage of
hulls). Other results (9, 10) showed that a low level of available
calcium in the soil had no noticeable effect on the nature of the
foliage or flower production of peanuts, but it decreased the yield
and quality of fruit. The pods also had low shelling percentages
of seed, and many of the seed had dark plumules (Figure 1).
1Agronomist, Florida Agricultural Experiment Station, Gainesville, Florida.
2 Numbers in parentheses refer to Literature Cited.
Figure 1.-Top, normal Florigiant peanuts; bottom, seed with dark plumule
caused by calcium deficiency (some mechanical damage to end and edge of coty-
ledons caused by opening seed). Other photographs of dark plumule of peanuts
caused by calcium deficiency have been published (5, 7, 10).
Field experiments (13, 15) have also shown that lime in-
creased yields of peanuts, while more recent field experiments
(14) substantiate previous findings that lime improves the qual-
ity of the seed.
Experiments in Florida on the effect of boron on peanuts
have all been with soil cultures. Usually boron deficiency mark-
edly decreased the yield and quality of seed, and sometimes
caused striking foliar symptoms. Different soils gave somewhat
different results. For example, Early Runner peanuts grown
without an application of boron to Blanton fine sand (11)
scarcely developed visible foliar deficiency symptoms for this
element, and the symptoms were not observed until late in the
Figure 2.-Early Runner and Spanish with "hollow-heart defect" (7, 11)
caused by boron deficiency. Normal Early Runner seed in top line.
Figure 3.-Branch of 12-week-old Florigiant plant grown on Lakeland fine
sand shows boron deficiency symptoms on the base of the shoots. Boron applied
to the soil at 0.02 ppm as H3BO: in water around the plants three weeks before
this picture was taken resulted in new top growth free of the symptoms.
growing season. Even so, seed yields were greatly reduced and
many of the seed had the "hollow-heart defect" (Figure 2). This
defect, first attributed to boron deficiency in 1957 (11), is a
knurled, hollow, tan or brown area between the cotyledons.
In contrast, boron deficiency in other experiments (5, 9, 10)
with Florigiant peanuts on Lakeland fine sand caused striking
foliar symptoms. Shoots were stubby; leaves frequently were
mottled, and sometimes wilted and abscissed. Dark areas ap-
peared in the internodes of the branches, and the stems some-
times developed long cracks. After the plants developed the foliar
symptoms, 0.02 ppm of boron as H3B03 in water around the
plants resulted in new shoot growth free of the symptoms (Fig-
ure 3); thus mid-season correction was easily made. Contrary to
appearance, roots and shoots of plants grown without an applica-
tion of boron frequently weighed more than those where boron
was applied to the soil. Boron deficiency did not decrease the total
number of flowers produced, but changed the flowering pattern.
With deficiency, flowering was moderate and continued later into
the season. The deficiency greatly decreased the yield of seed,
Figure 4.-"Hollow-heart defect" of Florigiant peanuts caused by boron de-
ficiency (5, 7, 10) when grown on Lakeland fine sand. Boron at the rate of 0.2
ppm as HaBO. applied to the soil before seeding prevented the abnormality.
and many of the seed produced had "hollow-heart defect"
Recent data (5, 8) indicate that peanuts grown with com-
plete fertilization, except boron, developed striking foliar de-
ficiency symptoms, while plants did not exhibit the symptoms
when grown on the same soil without treatments of any kind.
Thus these soil experiments suggest that visual boron deficiency
symptoms of foliage do or do not develop depending possibly on
imbalance between boron and other nutrients. Furthermore, im-
balanced fertilization produced fewer peanuts than no treatment
Varietal comparisons have been made only with Early Run-
ner and Dixie Runner (11); Early Runner gave a larger in-
crease in yield from an application of boron.
Additional research comparisons were made of the effect of
calcium and boron on 'Starr Spanish', 'Early Runner', 'Line
F416' and 'Florigiant' varieties. Both solution and soil cultural
experiments were conducted, but the soil cultures were used only
in boron evaluations.
Plants of the solution experiments were grown in a growth
chamber using the complete nutrient solution No. 2 of Hoagland
and Arnon (12), except that the major nutrient elements were
at half concentration. The complete solution contained 80 and
0.5 ppm of calcium and boron, respectively. In all experiments
the boron was from H3BOa. Modifications of the complete nutri-
ent solution were made for growing plants without boron, with-
out calcium, and with a low level of calcium (5.0 ppm of calcium
from calcium sulfate). A trace of calcium and boron probably
was in the nutrient solution even where none was purposely
added. Aeration of the culture solutions was done by a device
previously described (6). These were short period experiments
(ten weeks), and flowers were counted five days of the week,
after flowering began. At the termination of the experiment,
shoot and root weighing were made.
Lakeland fine sand in large glass containers was utilized in
the soil experiments. After the peanuts were grown to maturity,
foliage, roots, and mature pods were weighed. The mature pods
were shelled and the seed graded. Flowers were counted as pre-
viously indicated for 15 weeks after the flowering began. Details
of the treatments and manner of conducting the experiments
were the same as published (9) for 1964.
RESULTS AND DISCUSSION
Solution Studies with Calcium and Boron
Peanuts grown without calcium in the nutrient solution (con-
tained a trace of calcium as impurities) did not progress beyond
the seedling state (Figure 5) and soon died. All four varieties
gave about the same response. Obviously flowers could not be
produced by these plants.
A low level of calcium (5 ppm) in the nutrient solution
(Table 1) greatly decreased foliage, root and flower production
of all varieties. However, the low level of calcium was sufficient
for the development of some flowers. The Florigiant grown with
complete nutrient solution (high calcium) was much smaller
than the other varieties grown with the same treatment. Presum-
ably the Florigiant grows slowly early in the season, but later
catches up rapidly with other varieties. Thus the low level of
calcium attainable in nutrient solution will decrease foliage,
flower, and root production; but under soil conditions the level of
Figure 5.-Photograph showing the effect of calcium deficiency on Early Run-
ner peanut grown in nutrient solution. Peanuts in left jar did not receive calcium
and did not get beyond this stage before dying. Plants in right jar grew well with
80 ppm of calcium in the nutrient solution.
Table 1.-Effect of boron and calcium deficiencies on foliage, root, and flower
production of peanut varieties grown in solution culture for 10 weeks.'
Dry Yield per Culture Total
Nutrient Foliage Roots Culture
g g No.
Starr Spanish, Complete 127.6 11.9 437
Starr Spanish, Without boron 10.2 2.2 2
Starr Spanish, Low calcium 20.6 4.2 97
Starr Spanish, Without boron and 9.2 2.4 21
with low calcium
Early Runner Complete 139.6 9.8 372
Early Runner Without boron 4.0 1.6 1
Early Runner Low calcium 12.7 3.1 28
Early Runner Without boron and 7.2 1.4 3
with low calcium
Line F 416 Complete 142.1 20.0 164
Line F 416 Without boron 6.0 1.9 0
Line F416 Low calcium 21.7 8.0 43
Line F 416 Without boron and 7.1 3.3 0
with low calcium
Florigiant Complete 38.7 5.0 57
Florigiant Without boron 15.7 2.6 21
Florigiant Low calcium 15.9 3.3 41
Florigiant Without boron and 9.5 1.9 22
with low calcium
LSD 5% 10.8 1.5
LSD 1% 14.8 2.0
'Peanuts planted 5/5/64 and harvested 7/14/64. Flowers were counted during last five
2 The complete nutrient solution contained 80 and 5 ppm of calcium respectively, for com-
plete and low calcium nutrition. The complete nutrient solution contained 0.5 ppm of boron
calcium would not likely be similarly deficient. However, low soil
calcium most likely will affect yield and quality of seed (9).
Starr Spanish, Early Runner, Line F 416, and Florigiant va-
rieties of peanuts, when grown without boron but otherwise with
a complete nutrient solution, began to develop foliar deficiency
symptoms in about 4 weeks. The early stages of the deficiency
symptoms for Starr Spanish is shown in Figure 6. The longer the
plants were without boron, the more severe the symptoms
became, and gradually plants of all varieties died. An occasional
flower developed before deterioration became excessive. The de-
ficiency symptoms, previously described, were similar for all
varieties, but Starr Spanish, and Early Runner developed them
slightly earlier than the other varieties. Boron addition to the
nutrient solution soon after the symptoms appeared caused all
varieties to recover quickly.
Figure 6.-Containers of Starr Spanish peanuts grown with (right, 0.5 ppm of
boron as H3B0s) and without (left) boron in the nutrient solution. Plants in left
container have just begun to develop boron deficiency symptoms.
Figure 7.-Early Runner (left) and Florigiant (right) plants, 13 weeks of age,
recovering from boron deficiency. Seedlings of both varieties were grown for seven
weeks with an incomplete nutrient solution with respect to boron, then changed
to complete nutrient solution containing 0.5 ppm of boron from H3BOs. Each seed
of this test was selected to weigh 0.7 gram.
The recovery of Early Runner and Florigiant peanuts from an
extended period of boron deficiency is shown in Figure 7. The
Florigiant variety tolerated the extended boron deficiency stress
much better than Early Runner, which suggests a varietal differ-
ence in tolerance to boron deficiency. However, no analyses were
made to compare the boron content of the seeds, and the two va-
rieties could have had a different amount present.
An absence of boron in the nutrient solution markedly de-
creased yields of foliage and roots (Table 1) of peanuts har-
vested 10 weeks after planting. Flower counts for this period
usually were negligible.
Soil Studies with Boron
Results of the soil experiments in which the varieties of pea-
nuts were compared are shown in Figures 8 and 9 and Table 2.
Without an application of boron the weight of foliage and roots
in most cases was higher, but the yield of peanuts in all cases
was decidedly lower. The lack of boron greatly decreased the
shelling percentage of good seed for all varieties. Furthermore,
this deficiency in all cases increased the percentage of hulls and
of one-compartment pods. The cause of the high percentage of
one-compartment pods is not clear. However, conditions such as
failure of pollen tube growth, viability of pollen, abortion after
Figure 8.-Line F 416 peanuts grown on Lakeland fine sand with complete
fertilization and lime, except ones at right were without boron. The boron appli-
cation to the soil was at the rate of 0.2 ppm from H3BOs.
Figure 9.-Effect of boron on the yield of different varieties of peanuts when
grown on Lakeland fine sand. From top, varieties are Starr Spanish, Early Run-
ner, Line F 416, and Florigiant. Boron was applied to the soil at the rate of 0.2
ppm from H:;BO,. Right column, complete fertilization and lime, including boron;
left column, same except without boron.
Table 2.-Effect of boron1 applied to Lakeland fine sands in 1964 on flowering and average dry yield per culture of foliage, root, and
fruit and on grade of peanuts of four varieties.
Foliage Roots Mature Normal! Hulls' One Average
Variety Lime and Unshelled Plump Compart- Flowers'
Fertilizer Peanuts Seed ment per Culture
Pods8 in 15 Weeks
g g g % % % No.
Starr Spanish Complete 65 21 70 59 24 9 321
Starr Spanish Complete
except boron 100 33 6 13 56 57 843
Early Runner Complete 100 22 62 60 30 13 420
Early Runner Complete
except boron 98 32 1 0 55 100 284
Line F 416 Complete 98 26 63 54 35 3 324
Line F 416 Complete
except boron 95 40 3 7 59 66 362
LSD 5% 18 7 14 8 18 18
LSD 1% 24 9 19 11 24 25
Florigiant5 Complete 115 43 105 69 27 10 398
except boron 164 70 5 13 54 71 458
LSD 5% 25 9 25 14 9 11
LSD 1% 34 12 34 19 12 16
1 Boron was applied to the soil at the rate of 0.2 ppm from HBO,.
SWeight percentage based on mature unshelled peanuts.
3 Percentage based on number of pods.
SFlowers not counted holidays and weekends.
SIn another experiment grown with the same treatments, conditions, and soil and at the same time.
fertilization, or interference in some other stage of fruit develop-
ment could be involved. Total flower production (Table 2) fre-
quently was greater where boron was not applied. Thus no clear
relation was evident between number of flowers and seed produc-
tion in these tests.
Visual boron deficiency symptoms of the foliage were similar
for the varieties, though long cracks were not observed on the
branches of Starr Spanish.
This summary is based on both previous work in Florida and
the results presented in this publication.
Peanuts did not survive the seedling stage when grown with-
out calcium in the nutrient solution. Apparently seed of peanuts
do not contain enough calcium to support the seedling very long.
A low level of calcium (5 ppm as compared to 80) in the nutrient
solution greatly reduced seedling growth, but even with this low
level a few flowers were produced. Withholding calcium from the
nutrient solution during the last half of the growing season ap-
preciably decreased foliage, flower, root, and fruit production;
and without an external supply of calcium around the growing
fruit, seed production was negligible. This appeared to be due to
inadequate internal movement of calcium through the peg. Thus
by rigidly controlling calcium at a low level in the nutrient solu-
tion all phases of peanut growth have been adversely affected.
In contrast, a low level of calcium in the soil has no noticeable
affect on foliage, flower, and root development. Presumably the
difference in the results from the two types of experiments was
due to a lower level of calcium attainable in nutrient solution.
However, the low level of calcium in the soil did greatly decrease
the yield and quality of the fruit. Many of the peanuts thus pro-
duced had seed with dark plumules, and the peanuts had high
percentages of hulls.
Little information has been obtained concerning the compara-
tive effect of calcium on varieties grown in the state, but presum-
ably the large-seeded varieties require more calcium than the
All four varieties of peanuts grown in nutrient solution with-
out boron began to develop deficiency symptoms in about four
weeks, after which they gradually deteriorated and slowly died.
The plants made some growth with an occasional flower develop-
ing before deterioration became excessive. Visual symptoms of
boron deficiency symptoms were similar among varieties, but
Starr Spanish and Early Runner developed them slightly earlier
than the others. When boron was added to the nutrient solution
soon after the symptoms first appeared all varieties rapidly re-
covered. However, Florigiant recovered more rapidly from a pro-
longed period of boron deficiency than Early Runner. Presum-
ably this was a varietal difference, but analysis for boron content
of the seed was not made.
A low level of boron in the soil often increased foliage and root
weight (contrary to appearance) but invariably decreased seed
production. The deficiency usually did not decrease total flower
production, but the distribution pattern was changed. Striking
deficiency symptoms frequently were observed. Shoots were
stubby and leaves often became mottled, and at times wilted
and abscissed. Dark areas developed in the internodes and some-
times long cracks developed in the stems. Many of the seed had
"hollow-heart defect," while the percentage of hulls and per-
centage of one-compartment pods greatly increased.
A lack of available soil boron, which caused poor seed yields,
did not always cause visual foliar symptoms of boron deficiency
or they appeared to a slight degree, late in the season. The se-
verity of foliar deficiency symptoms seemed to be related to
imbalance between boron and other nutrients. In one experiment,
plants grown with complete fertilization except boron, developed
striking foliar deficiency symptoms and produced few peanuts.
In contrast, plants grown on the same soil without fertilization
of any kind were small. These did not develop foliar symptoms,
and yielded more peanuts than the ones grown with fertilizer
The effect of boron on the four varieties compared was simi-
lar. However, in earlier experiments boron increased the yield of
Early Runner more than Dixie Runner. There are varietal differ-
ences in response, but more research is needed to define the dif-
A moderate application of calcium to the soil for peanut pro-
duction has been beneficial in several cases. Whether calcium
should be applied and the rate and manner of application depend
on a number of factors. Among them are degree of soil acidity,
soil type, previous treatment, facilities available, and local con-
A low level of boron in the soil did not always cause foliar de-
ficiency symptoms, but the symptom seem to develop rapidly
when there was an imbalance between boron and other nutrients.
After the plants developed deficiency symptoms, 0.02 ppm of bo-
ron applied around the plants caused the new growth to be free of
the symptoms. In most of these experiments, an application of 0.2
ppm of boron to the soil before seeding had a decided beneficial
effect on the peanuts. This is equivalent to 2.3 pounds of boric
acid or 3.5 pounds of borax per acre. Thus, the amount required
is small. Little research has been conducted on peanuts as to the
rate when boron becomes toxic. A large amount is toxic to other
plants. Where boron application for peanuts is desirable, possibly
a safe rate would be the same, or not much larger than used in
1. Bledsoe, R. W., and Henry C. Harris. 1950. The influence of mineral de-
ficiency on vegetative growth, flower and fruit production, and mineral
composition of the peanut plant. Plant Physiol. 25:63-77.
2. Bledsoe, R. W., C. L. Comar, and H. C. Harris. 1949. Absorption of ra-
dioactive calcium by the peanut fruit. Science 109:329-330.
3. Harris, Henry C. 1949. The effect on the growth of peanuts of nutrient
deficiencies in the root and pegging zone. Plant Physiol. 24:150-161.
4. Harris, Henry C. 1959. Research on peanuts during the last twenty
years. Soil and Crop Science Soc. of Fla. Proc. 19:208-226.
5. Harris, Henry C. 1963. Symptoms of nutritional deficiencies in plants.
Soil and Crop Science Soc. of Fla. Proc. 23:139-152.
6. Harris, Henry C. 1966. Aeration device for nutrient solutions. Crop
7. Harris, Henry C., and John B. Brolmann. 1963. Dark plumule of peanut
seed due to calcium deficiency and farther studies on boron deficiency of
the peanut. In Peanut Improvement Working Group Proc. p. 190-205.
July 29-31, 1963. Oklahoma State University, Stillwater, Oklahoma.
8. Harris, Henry C., and John B. Brolmann. 1966. Effect of imbalance of
boron nutrition on the peanut. Agronomy J. 58:97-99.
9. Harris, Henry C., and John B. Brolmann. 1966. Comparison of calcium
and boron deficiency of the peanut. I. Physiological and yield difference.
Agronomy J. 58:575-578.
10. Harris, Henry C., and John B. Brolmann. 1966. Comparison of calcium
and boron deficiencies of the peanut. II. Seed quality in relation to
histology and viability. Agronomy J. 58:578-582.
11. Harris, Henry C., and R. L. Gilman. 1957. Effect of boron on peanuts.
Soil Sci. 84:233-242.
12. Hoagland, D. R. and D. I. Arnon. 1950. The water-culture method for
growing plants without soil. Calif. Agri. Expt. Sta. Cir. 347. 32p.
13. Robertson, W. K., Curtis E. Hutton, H. W. Lundy, L. G. Thompson, and
R. W. Lipscomb. 1957. Effect of lime on some North Florida soils. Soil
and Crop Sci. Soc. Fla. Proc. 17:72-85.
14. Robertson, W. K., H. W. Lundy and L. G. Thompson. 1965. Peanut
responses to calcium sources and micronutrients. Soil and Crop Sci. Soc.
Fla. Proc. 25:335-343.
15. Thompson, L. G., Jr., and W. K. Robertson. 1959. Effect of rotations,
fertilizers, lime and green manure crops on crop yields and on soil fer-
tility, 1947-1957. Fla. Agr. Expt. Sta. Bull. 614. 60 p.