Group Title: Research report (North Florida Research and Education Center (Quincy, Fla.))
Title: Response of southern runner peanuts to lime, gympsum, and zinc
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 Material Information
Title: Response of southern runner peanuts to lime, gympsum, and zinc
Series Title: Research report (North Florida Research and Education Center (Quincy, Fla.))
Physical Description: 8 p. : ill. ; 28 cm.
Language: English
Creator: Rhoads, Fred ( Frederick Milton )
Shokes, Frederick M ( Frederick Milton ), 1943-
Gorbet, Daniel W ( Daniel Wayne ), 1942-
North Florida Research and Education Center (Quincy, Fla.)
Publisher: North Florida Research and Education Center
Place of Publication: Quincy Fla
Publication Date: 1991
Subject: Peanuts -- Effect of soil acidity on   ( lcsh )
Fertilizers   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (p. 8).
Statement of Responsibility: F.M. Rhoads, F.M. Stokes, and D.W. Gorbet.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00066094
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71171668

Full Text

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Research Report: NF-91-7


OF SN RS 931



F. M. Rhoads, F. M. Shokes, and D. W. Gorbet

North Florida Research and Education Center

University of Florida

C L Florida Agricultural Experiment Station
IFAS Institute of Food and Agricultural Sciences
University of Florida, Gainesville
[L, lv4 .m;p ,-1 i i-dl. t d i .i p.

Response of Southern Runner Peanuts to Lime,

Gypsum, and Zinc

F. M. Rhoads, F. M. Shokes, and D. W. Gorbet

Phytotoxicity occurs in peanuts growing on acidic soils with

high levels of zinc (Zn) (Johnson, 1987). Peanut leaf Zn

concentration has been shown to decrease when soil pH was increased

(Cox, 1990 and Parker et al., 1990). Zinc toxicity was observed in

peanuts having youngest mature leaf concentrations of Calcium (Ca)

and Zn to give a Ca/Zn ratio .of 50 or less (Parker et al., 1990).

Therefore, liming the soil can reduce the toxic effects of Zn by

reducing Zn concentration in plants and increasing Ca


Gypsum is recommended to supply calcium to the pegging zone of

peanuts in order to prevent the occurrence of low quality nuts.

However, the effect of gypsum on Zn uptake and the Ca/Zn ratio in

peanuts has not been extensively reported.

The objective of this research was to compare Ca and Zn

concentration in peanut plants grown in soil treated with different

levels of calcite, gypsum and Zn.


Soil was collected in plastic containers from the Ap horizon

of Norfolk loamy sand (fine-loamy, siliceous, thermic, Typic

Kandiudults) from an unfertilized area on the North Florida

Research and Education Center, Quincy. The soil was dried,

screened (with a non-metal screen) and weighed into plastic pots

(2.0 kg per pot). Each pot of soil was mixed with 0.26 g of 46%

triple superphosphate, 0.54 g of potassium sulfate, and 0.50 g of

magnesium sulfate in addition to Zn, calcite, and gypsum levels

shown in table 1. Soil and fertilizer mix was moistened with 300

mL of water and allowed to incubate in plastic bags for two weeks.

Peanuts (Southern Runner) were grown in the pots inside a

glasshouse for nine weeks.

At the end of the growing period tops and roots of all plants

were harvested, dried, and weighed. Only the data from the tops

are included in this report. After weighing, plant samples were

ground, ashed in a muffle furnace at 5000C and taken up in dilute

acid'(HC1). Solution Zn was determined with atomic absorption (AA)

spectroscopy and Ca was determined with flame emission (FE)


Soil samples were also collected from pots at the end of the

growth period and extracted with Mehlich-I and Mehlich-III soil

extractants. Soil pH was measured in a 1:1 v/v soil-water


The experimental design was a randomized complete block with

three levels of Zn, three levels of calcite, and one level of

gypsum applied to the soil for a total of twelve treatments. Level

of Zn was varied for each calcium source and rate. Analysis of

variance procedures were used to evaluate treatment effects on

peanut dry-weight (Steel and Torrie, 1960). Regression analyses

were used to evaluate soil-test Zn and Ca/Zn ratio in peanut


Table 1. Extractable soil calcium, soil-pH, dry-weight of peanuts, calcium and

zinc concentration of peanut tissue, and Ca/Zn ratio in peanut tissue

with different levels of zinc, calcite, and gypsum applied to the


Applied Calcium source Soil Dry-weight Tissue

Zinc and rate Calcium Soil-pH of peanuts Calcium Zinc Ca/Zn

ppm g/kg ppm g/pot % ppm


0 0 73 5.3 7.86at 0.62 31 198

5 0 80 5.3 7.96a 0.65 47 138

25 0 75 4.9 4.91b 0.46 114 41


0 1 355 5.4 7.96a 0.76 17 470

5 1 308 5.5 7.65a 0.70 22 327

25 1 360 5.6 6.47b 0.72 51 141

0 2 735 5.9 8.05a 0.80 12 685

5 2 858 5.9 7.77a 0.89 13 682

25 2 780 5.9 7.12a 0.88 28 316


0 2 453 5.3 7.09a 0.71 32 224

5 2 390 5.2 8.06a 0.68 54 126

25 2 460 5.0 3.78b 0.62 157 40

tValues within each calcium treatment followed by the

same letter are not

significantly different (P

significantly different (P

significantly different (P

significantly different (P <

> 0.05).

> 0.05).

> 0.05).

0.01) froi

Control and gypsum treatments are

The two levels of calcite are

Control and gypsum treatments

m calcite treatments.





Extractable soil calcium levels ranged from 73 to 858 ppm

(Table 1). Soil pH ranged from 4.9 to 5.9 and was reduced by high

Zn without calcite. The highest rate of Zn reduced peanut yield

with gypsum, 0 and 1 g/kg calcite (Tables 1 and 2). Calcite at 2

g/kg prevented Zn toxicity in Southern Runner peanuts with 50 lb

Zn/acre but gypsum had no effect (Table 1).

Tissue calcium increased with the addition of calcite and

gypsum but was not affected by Zn rate or Zn x Ca interaction

(Table 2).

Concentration of tissue Zn was influenced by Zn rate, Ca

treatment and interaction of Zn with Ca (Table 2). Soil pH

appeared to be more important for reducing Zn concentration and

toxicity in peanuts than extractable soil Ca.

Table 2. Analysis of variance for peanut dry-matter yield, tissue

zinc and tissue calcium.

Source df Yield Tissue Zn Tissue Cat

Zinc Rate 2 ** ** N.S.

Calcium Rate 3 ** **

ZnRxCaR 6 ** N.S.

tCalcium sources were calcite and gypsum. **,* indicate

significance at P = 0.01 and 0.05, respectively. N.S. = not


Although, tissue Zn decreased with increased soil pH, soil-

test Zn was highly correlated with rate of Zn applied to the soil

(Fig. 1). Rate of soil applied Zn accounted for more than 97% of

the variation in soil-test Zn. Mehlich-I extractant removed just

over 14% of applied Zn while Mehlich-III recovered about 20%. Both

extractants were highly correlated with applied Zn and should serve

equally well for estimating soil Zn status.

The critical Ca/Zn ratio for this test was 78 (Fig. 2). Only

two treatments showed Zn toxicity symptoms and both had a Ca/Zn

ratio below 50. Gypsum did not increase the Ca/Zn ratio or reduce

toxicity in Southern Runner peanuts (Table 1). Calcite at 2g/kg

counteracted the effect of high Zn rate on yield of peanuts and

increased the Ca/Zn ratio from 41 to 316. At Ig/kg applied

calcite, high Zn (25 mg/kg) reduced yield of peanuts but Ca/Zn was

above 140. Therefore, peanut plants showing toxicity symptoms had

Ca/Zn ratios below 50 but incipient toxicity occurred above the

critical Ca/Zn level.

Two tons of calcite per acre (2g/kg) raised soil pH to 5.9 and

prevented Zn toxicity in peanuts with 50 lb of applied Zn/acre.

Gypsum increased Zn concentration in peanuts and did not reduce Zn

toxicity. The critical Ca/Zn ratio in this test was 78 but

incipient Zn toxicity was observed at a Ca/Zn ratio of 141. Toxic

levels of soil-test Zn were 9.6 and 13.7 lb/acre for Mehlich-I and

Mehlich-III extractants, respectively.

Soil-Test Zn Vs Zn Rate
Mehlich 1 and Mehlich 3

Soil-Test Zn (ppm)

CD 0.987

CD 0.978


o Mehlich 1 Means
x Mehlich 3 Means
-- M1 1.22 + 0.144X

-s- M3 1.68 + 0.206X

0 5 10 15 20 25 30
Zinc Rate (ppm)

Figure 1. Regression analysis of soil-test zinc on rate of Zn
applied to the soil. CD = coefficient of determination.


Yield (g/pot)

x x

CD 0.608

Y 7.6; X or

- Y 0.783 + 0.0(

of Peanut vs Ca/Zn


x Trt Means

-t- L-P Model


374X; X < 78

0 100 200 300 400 500 600 700
Peanut Tissue Ca/Zn

Figure 2.

Relationship between peanut plant dry-weight and Ca/Zn
ratio in plant tissue. Data points are treatment means.
A linear-plateau (L-P) model is shown as determined from
regression analysis.



1. Cox, F. R. 1990. A note on the effect of soil reaction and

zinc concentration on peanut tissue zinc. Peanut Science


2. Johnson, W. C. 1987. Soil fertility. Chap. 3. In W. C.

Johnson (ed.) Georgia peanut production guide. Cooperative

Extension Service, Univ. of Georgia, and U.S.D.A. Athens,


3. Parker, M. B., T. P. Gaines, M. E. Walker, C. O. Plank, and J.

G. Davis-Carter. 1990. Soil zincand pH effects on leaf zinc

and the interaction of leaf calcium and zinc on zinc toxicity

of peanuts. Commun. In Soil Sci. Plant Anal., 21 (19 &


4. Steel, R. G. D., and J. H. Torrie. 1960. Principles and

procedures of statistics. McGraw-Hill, New York.

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