effect of wetting and drying on dtpa‐extractable fe, zn, mn, and cu in soils 1

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This article was downloaded by: [UQ Library] On: 15 November 2014, At: 00:43 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Communications in Soil Science and Plant Analysis Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lcss20 Effect of wetting and drying on DTPAextractable Fe, Zn, Mn, and Cu in soils A. Khan a & P. N. Soltanpour a a Department of Agronomy , Colorado State University , Fort Collins, Colorado, 80523 Published online: 11 Nov 2008. To cite this article: A. Khan & P. N. Soltanpour (1978) Effect of wetting and drying on DTPAextractable Fe, Zn, Mn, and Cu in soils , Communications in Soil Science and Plant Analysis, 9:3, 193-202, DOI: 10.1080/00103627809366800 To link to this article: http://dx.doi.org/10.1080/00103627809366800 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.

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Page 1: Effect of wetting and drying on DTPA‐extractable Fe, Zn, Mn, and Cu in soils               1

This article was downloaded by: [UQ Library]On: 15 November 2014, At: 00:43Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number:1072954 Registered office: Mortimer House, 37-41 Mortimer Street,London W1T 3JH, UK

Communications in SoilScience and Plant AnalysisPublication details, including instructions forauthors and subscription information:http://www.tandfonline.com/loi/lcss20

Effect of wetting and dryingon DTPA‐extractable Fe, Zn,Mn, and Cu in soilsA. Khan a & P. N. Soltanpour aa Department of Agronomy , Colorado StateUniversity , Fort Collins, Colorado, 80523Published online: 11 Nov 2008.

To cite this article: A. Khan & P. N. Soltanpour (1978) Effect of wetting anddrying on DTPA‐extractable Fe, Zn, Mn, and Cu in soils , Communications in SoilScience and Plant Analysis, 9:3, 193-202, DOI: 10.1080/00103627809366800

To link to this article: http://dx.doi.org/10.1080/00103627809366800

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of allthe information (the “Content”) contained in the publications on ourplatform. However, Taylor & Francis, our agents, and our licensorsmake no representations or warranties whatsoever as to the accuracy,completeness, or suitability for any purpose of the Content. Any opinionsand views expressed in this publication are the opinions and views ofthe authors, and are not the views of or endorsed by Taylor & Francis.The accuracy of the Content should not be relied upon and should beindependently verified with primary sources of information. Taylor andFrancis shall not be liable for any losses, actions, claims, proceedings,demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, inrelation to or arising out of the use of the Content.

Page 2: Effect of wetting and drying on DTPA‐extractable Fe, Zn, Mn, and Cu in soils               1

This article may be used for research, teaching, and private studypurposes. Any substantial or systematic reproduction, redistribution,reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of accessand use can be found at http://www.tandfonline.com/page/terms-and-conditions

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COMMUN. IN SOIL SCIENCE AND PLANT ANALYSIS, 9(3), 193-202 (1978)

EFFECT OF WETTING AND DRYING ON DTPA-EXTRACTABLE

FE, ZN, MN, AND CU IN SOILS1

KEY WORDS: Micronutrients, soil testing

A. Khan and P. N. Soltanpour2

Department of AgronomyColorado State University

Fort Collins, Colorado 80523

ABSTRACT

The study reported herein was intended to determine the ef-

fect of (i) wet-incubation and subsequent air-drying, and (ii)

oven-drying on DTPA-Fe, Zn, Mn, and Cu.

Analysis of wet-incubated soils showed significant decreases

in DTPA-Fe, Mn, and Cu at the 1% and Zn at the 10% level of proba-

bility. Air-drying of these moist-incubated soils increased the

levels of Fe, Zn, and Cu to values close to their original levels.

Levels of Mn sharply deviated from their original values after air-

drying of incubated soils. Correlation coefficients (r) between

the amounts of extractable nutrients in original air-dry soils

and wet-incubated soils were 0.54, 0.87, 0.91, and 0.13 for Fe,

Zn, Cu, and Mn, respectively. Oven-drying increased the levels of

DTPA-extractable micronutrients from 2 to 6 fold.

193

Copyright © 1978 by Marcel Dekker, Inc. All Rights Reserved. Neither this work nor any partmay be reproduced or transmitted in any form or by any means, electronic or mechanical, includingphotocopying, microfilming, and recording, or by any information storage and retrieval system,without permission in writing from the publisher.

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194 KHAN AND SOLTANPOUR

INTRODUCTION

Many soil testing laboratories in the Western USA use the DTPA

test to assess the availability of Zn and Fe and to a limited ex-

tent Cu and Mn. With respect to sample handling, it is generally

recommended that soil samples be air-dried as soon as possible,

after they are obtained from a field. However, moist samples are

sometimes submitted to the soil testing laboratories, and a week

or more may pass before these samples are air-dried for analyses.

The effect of wet-incubation and air-drying after wet-incubation

on DTPA-extractable micronutrients in the soil is unknown.A

Elgala and Maier reported a decrease in EDTA-extractable Fe

in soils kept at high moisture levels compared to low. The de-

crease in Fe was attributed to a relative increase in Ca under

the most moist condition. Increase in the amount of exchangeable

Mn following air-drying has been reported, and it was proposed

that available Mn should be determined in moist soil samples .

The objectives of the study reported herein were to determine

the effect of (i) wet-incubation and subsequent air-drying, and

(ii) oven-drying on DTPA extractable Fe, Zn, Mn, and Cu.

MATERIALS AND METHODS

Twenty-four soils from Colorado farms, with a wide range in

texture and relatively low levels of Fe and Zn (soils 5 to 28),

were used for the 1st part of this study (Table 1). These soils

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DTPA-EXTRACTABLE Fe, Zn, Mn, AND Cu 195

TABLE 1

Some Properties of Soils Used In This Study

Soil No.

12345678910111213141516171819202122232425262728

Texture

Sandy loamClay loamSilty clay loamLoamLoamy sandSandy loamLoamy sandSilty clay loamSilty clay loamClay loamLoamy sandClay loamSandy clay loamSandy clay loamSilty clay loamSilty clay loamSilty clay loamLoamy sandSandy loamSilty clay loamSilty clay loamLoamy sandClay loamSandy loamSandy clay loamSandy clay loamLoamy sandLoamy sand

Organic matter

%

0.81.41.61.20.70.60.60.91.03.00.61.41.11.01.81.61.80.71.71.21.70.52.01.01.71.40.30.4

PH

7.88.07.28.47.67.37.48.17.97.88.17.88.07.97.87.57.48.47.87.79.28.78.18.08.17.78.98.4

were analyzed for DTPA-extractable Fe, Zn, Mn, and Cu after air-

drying, grinding with a wooden roller, and passing through a 2-mm

stainless steel sieve ' . Fifty gram soil samples were placed

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196 KHAN AND SOLTANPOUR

in 250 ml Erlenmeyer flasks and then brought to 1/3 bar moisture

tension with demineralized water. The flasks were covered with

parafilm, and kept for one week at room temperature. Subse-

quently Fe, Zn, Mn, and Cu were determined in moist soil samples.

A subsample obtained from each moist soil sample was air-dried

and ground with a wooden roller to pass through a 2-mm stainless

steel sieve before determination of micronutrients.

The effect of oven-drying was evaluated using soils 1, 2,

3, and 4 (Table 1). The soils were analyzed before and after

oven-drying at 110°C for 48 hours.

RESULTS AND DISCUSSION

Incubation of moist soils caused a decrease in Fe, Mn, and

Cu levels in 23 out of 24 soils (Table 2). Using each soil as

a replicate, the mean decrease was statistically significant at

the 1% level for these three elements. The levels of zinc de-

creased as a result of incubation in 20 out of 24 soils. The

mean decrease for Zn was statistically significant at the 10%

level. Air-drying of incubated soils increased the levels of Fe,

Zn, and Cu to values close to their original levels; however, Mn

levels on the average were lower than the original levels. The

decrease in micronutrient availability associated with high mois-

ture levels has been observed through chlorosis of plants in

calcareous soils at different parts of the world4' 7) 8> 9> 10.

The incidence of chlorosis was associated with the production of

high levels of bicarbonate ions under wet conditions11' 12. The

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DTPA-EXTRACTABLE Fe, Zn, Mn, AND Cu 197

TABLE 2

Effect Of Wetting And Drying On DTPA-ExtractableMicronutrients

a.

SampleNn

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

X

Iron and

1

5.2

6.0

4.7

3.0

2.9

3.7

5.9

4.0

3.3

3.7

7.3

8.7

6.7

4.3

6.6

3.5

4.5

2.7

3.6

5.9

3.4

5.3

5.2

6.0

4.9a

Zn

Fe2

2.13.8

2.2

1.0

0.8

1.7

2.7

1.4

1.2

1.2

2.5

2.9

1.9

2.4

2.1

1.0

2.4

1.5

4.2

2.7

1.3

1.7

3.0

3.0

2.1b

3

5.

5.

4.

3.

2.

3.

5.

3.

2.

3.

7.

8.

5.

4.

7.

5.

7.

2.

3.

6.

4.

5.

5.

6.

5.

. . • HI-"08

1

4

8

6

4

6

9

0

6

6

9

9

40

9

9

8

2

5

4,8

.3

,1a

1

3.360.130.390.130.25

0.441.37

6.920.60

0.350.450.16

4.440.450.370.77

0.320.140.34

0.380.410.320.260.961.01a

Zn2

2.400.200.420.200.220.53

0.66

2.150.40

0.28

0.240.11

1.010.310.220.30

0.260.100.25

0.230.240.24

0.260.550.49a

3

2.980.180.410.22

0.330.55

1.15

3.500.71

0.430.540.38

2.070.640.54

0.911.570.230.40

0.480.520.390.35

0.830.85a

1 Original air-dry2 Soil incubated for 7 days at 1/3 bar moisture tension and

analyzed wet.3 Soil air-dried after 7 days of incubation

(continued...)

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198 KHAN AND SOLTANPOUR

TABLE 2. CONTINUED

b. Manganese and Cu

SampleNo.

5

6

7

8

9

10

1112131415161718192021

2223

2425262728

X

19.9

10.6

10.0

9.711.7

9.9

2.65.54.04.55.2

8.8

7.7

2.9

3.9

5.8

3.0

2.6

3.3

3.6

4.74.97.12.2

6.0a

Mn11.9

2.91.9

1.3

1.3

1.4

0.9

1.11.31.11.02.31.32.41.61.22.6

1.5

0.9

2.0

2.0

2.0

7.11.61.9b

. —.. .ppm.3i7 ^4.13.7

2.3

2.5

3.2

2.3

2.8

2.8

2.7

2.75.13.6

4.24.77.5

5.0

3.5

3.0

4.78.15.210.8

3.24.4c

10.66

0.54

0.26

1.00

0.92

0.81

0.31

0.45

0.33

0.33

0.78

1.41

1.80

0.27

0.88

0.80

0.88

0.47

0.62

1.11

0.74

1.12

0.51

0.49

0.73a

Cu2.0.42

0.41

0.21

0.71

0.58

0.55

0.18

0.49

0.29

0.22

0.43

0.72

0.78

0.24

0.51

0.41

0.41

0.35

0.35

0.66

0.41

0.66

0.41

0.33

0.45b

3.

6.610.47

0.24

0.95

0.84

0.68

0.37

0.55

0.35

0.34

0.79

1.35

1.35

0.35

0.93

0.89

0.83

0.51

0.65

1.15

0.81

1.23

0.65

0.59

0.73a1 Original air-dry2 Soil incubated for 7 days at 1/3 bar moisture tension and

analyzed wet.3 Soil air-dried after 7 days of incubation

*Figures under the same element followed by the same letter are notsignificantly different at the 1% level.

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DTPA-EXTRACTABLE Fe, Zn, Mn, AND Cu 199

data reported here, however, suggests that high moisture lowers

the micronutrient availability in the soil and this may be the

reason for chlorosis observed under these conditions.

Correlation coefficients for these 4 elements among values

obtained from (1) original air-dry soils, (2) soils incubated

at 1/3 bar moisture tension, and (3) those air-dried following

incubation, are given in Table 3.

The correlation co-efficients (r) for Fe, Zn, and Cu were

significant at the \% level, and those for Mn were not significant.

Analysis of dry soil did not reflect Mn status of these soils at

1/3 bar moisture tension. Sherman and Harmer proposed that soils

should be analyzed for Mn in their field moist conditions. The

correlation coefficient for Fe between original air-dry soils and

TABLE 3

Correlation Matrices for Fe, Zn, Mn, and Cu.

Fe Zn Mn Cu

2

3

1

0.54**

0.86**

1

0.87**

0.92**

1

0.13

-0.04

1

0.91**

0.95**

1) Original Air-dry

2) Soil incubated for 7 days at 1/3 bar moisture tension andanalyzed wet.

3) Soil air-dried after 7 days of incubation.**

Values were significant at the 1% level.

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Page 10: Effect of wetting and drying on DTPA‐extractable Fe, Zn, Mn, and Cu in soils               1

200 KHAN AND S0LTANP0UR

those incubated at 1/3 bar tension was significant, but small.

However, more research is needed to determine effect of different

moisture levels and drying and wetting cycles on extractable

levels of Mn and Fe.

The superiority of one method of extraction over the other

for Mn and Fe should be established by further research. Zinc

and Cu levels in moist and dry soils are highly correlated and the

soils could be analyzed wet or dry for determining availability

indices of these elements.

Pven-drying increased the DTPA-extractable levels of Fe, Zn,

Mn, and Cu from 2 to 6 fold (Table 4). This may be due to re-

lease of these elements from organic matter.

TABLE 4

The Effect Of Pven-Drying On PTPA-Extractable Fe, Zn, Mn and Cu.

SoilNo.

1

3

4

5

X

Air-dry

4.1

2.8

3.1

2.9

3.2a*

FeOven-dry

16.3

15.3

19.5

15.1

15.8b

A.P.

0.60

0.20

0.30

0.50

0.40a

Zn0.0.

ppm - -

0.97

0.58

0.86

1.03

0.86b

MnA.O.

5.0

11.4

14.0

6.2

9.2a

O.P.

17.1

21.1

32.6

27.9

24.7b

CuA.P.

0.38

0.34

0.37

0.37

0.37a

O.P.

0.73

0.88

0.93

0.87

0.85b

*

Figures under the same element followed by different letters are

significantly different at the 1% level.

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DTPA-EXTRACTABLE Fe, Zn, Mn, AND Cu 201

SUMMARY AND CONCLUSIONS

The results and conclusions based on the work reported here

are:

(1) Soils may be analyzed in wet or dry conditions for Zn

and Cu. However, critical levels used should reflect

the moisture condition of the soil.

(2) Manganese availability index of wet soils is not corre-

lated with that of respective dry soils. For Fe there

is significant correlation between wet and dry availa-

bility indices; however, the correlation coefficient

value is small (0.54). Superiority of one method over

another for these elements should be established.

(3) Solubility of micronutrients decreases upon incubation

of moist soils. This phenomenon may explain the fre-

quent occurrence of chlorosis under conditions of in-

creased moisture levels.

(4) Oven-drying increases the DTPA-extractable levels of

Fe, Zn, Mn, and Cu to a large extent.

REFERENCES

1. Published as scientific series paper No. 2283.

2. Graduate Assistant and Associate Professor, Department ofAgronomy, Colorado State University, Fort Collins, Colorado.

3. Lindsay, W. L. and W. A. Norvell. 1969. Development of aDTPA micronutrient test. Agron. Abstr. p. 84.

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202 KHAN AND SOLTANPOUU

4. Elgaia, A.M., and R.H. Maier. 1964. Chemical forms of plantand soil Fe as influenced by soil moisture. Plant Soil.21:201-212.

5. Sherman, G.D. and P.M. Harmer. 1942. The manganese-manganicequilibrium of soils. Soil Sci. Soc. Amer. Proc. 7: 398-405.

6. Soltanpour, P.N., A. Khan, and W. L. Lindsay. 1976. Factorsaffecting DTPA-extractable Fe, Zn, Mn, and Cu from soils.Comm. Soil Sci. Plant Anal. 7(9): 797-821.

7. Olomn, M.O. and G.J. Racz. 1974. Effect of soil water andaeration on Fe and Mn utilization by flax. Agron. J. 66:523-526.

8. Ryan, P., J. Lee, and T.F. Peebles. 1967. Trace elementsproblem in relation to soil units in Europe. Food, and Agri-culture Organization of United Nations. World Soil Resourcesreport #31.

9. Tarania, L.F. 1973. Changes in the redox potential andavailable Fe content during the flooding and subsequent dry-ing of grey forest soil. Abstracted in Soils Fert. 37:(791), 1974.

10. Wallace, A., E.M. Romney, and G.W. Alexander. 1976. Limeinduced chlorosis caused by excess irrigation water. Commun.Soil Sci. Plant Anal. 7 (1): 47-49.

11. Boxama, R. 1972. Bicarbonate as the most important soilfactor in lime induced chlorosis in Netherlands. Plant Soil.37: 233-243.

12. Lindsay, W.L. and D.W. Thorne. 1954. Bicarbonate ion andoxygen level as related to chlorosis. Soil Sci. 77:271-279.

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