Group Title: Research report (North Florida Research and Educaiton Center (Quincy, Fla.))
Title: Copper and management toxicity of peanuts
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00066122/00001
 Material Information
Title: Copper and management toxicity of peanuts
Series Title: Research report (North Florida Research and Educaiton Center (Quincy, Fla.))
Physical Description: 6 leaves : ill. ; 28 cm.
Language: English
Creator: Rhoads, Fred ( Frederick Milton )
North Florida Research and Educaiton Center (Quincy, Fla.)
Publisher: North Florida Research and Education Center
Place of Publication: Quincy Fla
Publication Date: 1994
 Subjects
Subject: Peanuts -- Toxicology   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: F.M. Rhoads.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00066122
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71187784

Full Text


NFREC Res. Rpt. 94-6




COPPER AND MANGANESE

TOXICITY OF PEANUT ITS

rIdrston Science
JAN 1 4 1994
University of Florida
F. M. Rhoads



NORTH FLORIDA RESEARCH AND
ED UCA TION CENTER, 0 UINC Y


Florida Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville


UNIVERSITY OF

SFLORIDA

institute of Food and Agricultural Sciences









COPPER AND MANGANESE TOXICITY OF PEANUTS


F. M. Rhoads

Several pesticides used on peanuts contain copper (Cu) and
manganese (Mn) and their continued use may create high
concentrations of Cu and Mn in the soil. Disposal of poultry
manure on soils used to produce peanuts may also increase Cu and
Mn levels in the soil. These metals have been shown to be toxic to
plants when present in the soil in high concentrations. Toxic
concentrations vary with plant species and cultivar as well as with
soil pH.
A relationship between soil-test Cu and/or Mn and potential
toxicity in peanuts would allow growers to identify fields where Cu
and Mn could potentially be toxic before committing seed and other
inputs to each field. Toxicity in peanuts due to Cu and Mn can be
verified by tissue analysis if critical toxicity concentrations
(CTC) are known.
The objectives of this report were to determine (1) Mehlich-1
extractable levels of soil Cu and Mn that cause toxicity in peanuts
at two soil pH levels, and (2) critical toxicity concentrations of
Cu and Mn in peanut tissue.

METHODS AND MATERIALS
SAn experiment was conducted in a greenhouse in the spring of
1993. Seed of 'Florunner' cultivar were planted in pots containing
2 kg of soil each. Soil received Cu additions as copper sulfate in
amounts of 0, 100, 200, 400, and 800 mg kg"1 Cu, and Mn additions
as manganese sulfate in amounts of 0, 100, 200, 300, and 400 mg kg''
Mn. Each level of Cu and Mn received two levels (0 and 3 g per
pot) of calcium oxide as a liming material giving a total of 18
treatments. Each treatment was replicated four times. The
following determinations were made: soil pH, Mehlich-1 extractable
soil Cu and Mn plus dry-weight of shoots and roots and their Cu and
Mn concentrations. Regression analyses were used to determine the
relationship between soil-test Cu or Mn and potential toxicity in
peanuts.

RESULTS AND DISCUSSION

Lime application did not influence Mehlich-1 extractable soil-
test copper because about 2/3 of the applied Cu was recovered with
or without lime (Figure 1.). Regression analysis showed a
different relationship between plant growth and soil-test Cu in
limed soil compared to unlimed soil (Figure 2.). Plant dry-matter
yield with no lime, Cu or Mn was 20.25 g pot'. Analysis of
variance showed that the least significant difference (LSD.0 )
between treatments was 3.79 g pot"'. Using regression analysis
results shown in figure 2, the soil-test Cu level with no lime that
is expected to cause a significant growth reduction can be
* calculated as follows: [(20.25-3.79)-20.65]+(-0.061)=69 ppm. Since
plant dry-weight with lime but no Cu or Mn was 22.05 g pot"1, the
soil-test Cu level with lime that is expected to cause a









Soil-test vs Applied Cu

Soil-test Cu (ppm)
700
r = 0.971
600 ..-....... --. .....-- .........- .......

600
500 -- -- -----

400 -

300- -
3 0 0 . ...... -.. ... .. ........ ....
200 x No lime

100 x o 3 g lime/pot
---- Y-14.06+0.666X

0 200 400 600 800 1000
Applied Cu (ppm)

Figure 1. Influence of lime on soil-test copper as a function of
applied copper.

Peanut: Dry-wt vs Soil-Cu

2Dry-wt (g/pot)
25


20
\x 88 -0.881
(soil pH 6.0)
15 ...

0 x No lime

r -0.869 o 3 g lime/pot
5- Y-20.65-0.061X

(soil pH 4.7) Y-22.41-0.019X
0 x ,
0 100200300400500600700
Soil-test Cu (ppm)

Figure 2. Influence of lime on dry-weight of peanut shoots (tops)
as a function of soil-test copper.









* significant growth reduction can be calculated also as follows:
[(22.05-3.79)-22.41]-(-0.019)=218 ppm. Lime reduced peanut tissue
Cu levels and the toxicity of soil-Cu to peanuts without
influencing its extractability. Since lime reduced Cu uptake it
may decrease the rate of movement of Cu across the root membrane
or the calcium in lime may competitively interfere with Cu uptake.

Lime reduced Mehlich-1 soil-test Mn by more than 50% as shown
by an average extractable soil-Mn of about 46% of applied Mn with
no lime and 20% with lime (Figure 3.). Since soil-test calibration
is based on a relationship between availability and extractability
of nutrients, lime was expected to reduce availability of Mn to
peanuts. Soil-test Mn levels, with or without lime, expected to
cause a significant reduction in growth can be calculated in a
manner similar to that of Cu using the regression equations in
figure 4. For unlimed soil, the soil-test Mn expected to cause a
significant growth reduction of peanut was [(20.25-3.79)-21.57]+(-
0.146)=35 ppm. With lime, the soil-test Mn level expected to
significantly reduce peanut growth was [(22.05-3.79)-23.74]+(-
0.112)=49 ppm. The difference between soil-test Mn levels of 35
and 49 ppm was not significant (P>0.05) according to analysis of
variance. Thus, soil-test levels of Mn expected to reduce peanut
growth with lime were similar to those expected to reduce it
without lime.

These data suggest that there is cause for concern when peanut
fields contain soil-test Cu above 69 ppm and/or Mn above 35 ppm.

Plants showing toxicity symptoms can be analyzed to determine
if Cu and/or Mn may be the cause. Results from this test showed
that Cu levels above 40 ppm in the above ground tissue of peanut
were definitely toxic (Figure 5.) and Mn levels above 1000 ppm were
definitely toxic, also (Figure 6.). However, there was a trend
toward reduced plant growth with Cu concentrations in the range of
10 to 40 ppm and a similar trend was observed for Mn in the range
of 100 to 1000 ppm.









Soil-test vs Applied Mn


250
x
200 --- ---- ...
r 0.893
150-
x

10 0 ...........- .. .. ....... x N o lim e
x r 0o 3 g lime/pot
r 0.907
50 .... -. Y10.12+0.456X

Y-15.94+0.201X
0
0 I I I
0 100 200 300 400 500
Applied Mn (ppm)

Figure 3. Influence of lime on soil-test manganese as a function
of applied manganese.

Peanut: Dry-wt vs Soil-Mn


25Dry-wt (g/pot)
25


x No lime

o 3 g lime/pot

-- Y-21.57-0.146X

--- Y-23.74-0.112X


0 50 100 150 200 250
Soil-test Mn (ppm)


Figure 4. Influence of lime on dry-weight of peanut shoots (tops)
as a function of soil-test manganese.







Peanut: Dry-weight vs Shoot Cu


25Dry-Weight (g/pot)
25


20 -


15 -


10 -


5 -.... --


1 2 3
Copper in Shoots (log-ppm)


Figure 5.




25


Dry-weight of peanut shoots (tops) as influenced by
copper concentration of tissue. (log of 1 = 0, log of 10
= 1, log of 100 = 2, log of 1000 = 3, log of 10000 = 4).


1 2 3
Manganese in Shoots (log-ppm)


Figure 6.


Dry-weight of peanut shoots (tops) as influenced by
manganese concentration of tissue. (log of 1 = 0, log of
10 = 1, log of 100 = 2, log of 1000 = 3, log of 10000 =
4).




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