COMMUN. SOIL SCI. PLANT ANAL., 31(9&10), 1121-1127 (2000)

Redistribution of Copper in Alfisols UnderSubmergence. II. Applied Copper

J. K. Sahaa,1 and Biswapati Mandalb

aIndian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal, M.P. Pin-462038, IndiabDepartment of Agricultural Chemistry and Soil Science, Bidhan ChandraKrishi Viswavidyalaya, P.O. Kalyani, Dist. Nadia, West Bengal Pin-741235,India

ABSTRACT

Soil submergence for growing wet land rice creates typical chemicalenvironment which is likely to affect availability of applied fertilizer copper(Cu) to the crop by transforming it into various soil fractions. An experimentwas undertaken to study the effect of organic matter (as starch) applicationon the transformation of applied Cu in Alfisols under submergence. Copperwas applied either at the beginning or after 15 days of submergence(presubmergence). Results show that more than 85% of the applied Cu wasdistributed in water soluble plus exchangeable (WSEX), organicallycomplexed (OC), and amorphous iron oxides bound (AMOX) fractions atthe beginning of incubation. Submergence caused decrease in WSEX, andOC [in Purulia district (S,) soil only] fractions and increase in AMOX andresidual Cu fractions of applied Cu. About 15% of the applied Cu wastransformed into inactive residual fraction at the end of 60 days of

1Corresponding author.

1121

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1122 SAHA AND MANUAL

submergence. Copper applied in 15 days presubmerged soils transformed toa lesser extent into residual fraction than that applied in 0 day presubmerged(i.e., no presubmergence) soils. Application of organic matter in S, soilmobilized applied Cu from OC to AMOX fraction and reduced nettransformation into residual fraction. Lower net transformation into residualfraction suggests that Cu may be applied in 15 days presubmerged soil for itshigher use efficiency in rice crop grown in Cu deficient Alfisol.

INTRODUCTION

Copper, an essential plant nutrient when applied to soil undergoes variousreactions with soil components leading to decrease in its plant availability. Suchreactions which include sorption, complexation, precipitation and occlusion differin their magnitude in different soils in modifying the availability of appliednutrients. Submerging soil creates typical chemical environment where changesin pH and redox potential control the solubility as well as affinity of elementswith soil components. Such modified chemical environment is likely to causetransformation of applied Cu into various fractions leading to its very low useefficiency to rice crops. Knowledge on such transformation is helpful inunderstanding availability of the applied Cu as well as formulating strategy for itsmanagement towards increasing availability. Rice farmers often keep their fieldsunder puddled condition for a week or so before transplanting the seedlingspresumably to ensure the decomposition of weeds. They also use bulky organicmanure such as farmyard manure which is thoroughly mixed with soil at the timeof puddling (an operation involving tilling of puddled soil before transplanting ofrice seedlings). These practices viz., presubmergence of soil before transplantingand use of organic manures are likely to modify the transformation of appliedmicronutrients and thus their availability to rice plants. Mandai and Mandai (1990)studied transformation of applied Zn in a rice growing soil. Very little informationis however, available with respect to the transformation of applied Cu inwaterlogged soil.

The following experiment was conducted to study (1) the transformation ofapplied Cu in Alfisols under submergence and (2) effect of presubmergence andorganic matter on such transformation.

MATERIALS AND METHODS

Details of the soils used in this experiment and organic matter treatment imposed,and submergence-incubation procedure were described in the part I of this paper(Saha and Mandai, 2000). Copper was applied in the soils at 5 ug g 1 asCuSCy5H2O. Copper treatments were imposed either at 0 day of incubation(i.e., no presubmergence) or at 15 days after incubation (i.e., presubmergence).

REDISTRIBUTION OF COPPER IN ALFISOLS. II 1123

Treated soils were incubated in the laboratory at submergence following theprocedure described in Saha and Mandai (1998). The soil samples were analyzedfor different fractions of Cu at periodic intervals of incubation following the methodas described in Saha and Mandai (1998). Content of applied Cu in each fractionwas determined as the difference between value in Cu treated and no Cu treatedsamples.

RESULTS AND DISCUSSION

Results of this study are presented in Table 1. Content of applied Cu hi afraction is expressed as percent of applied amount recovered in that fraction. Eachfraction of Cu content was discussed separately for their changes duringsubmergence.

Water Soluble Plus Exchangeable Fraction (WSEX)

With the progress of incubation, the mean recovery decreased to a minimum at15th day after incubation. Such decrease in recovery of applied Cu in WSEXfraction might be due to its precipitation as hydroxides, hydroxycarbonates, orsulphides (Papadopoulos and Rowell, 1989; Katyal, 1977) or to its transformationinto some other fractions. It increased marginally thereafter with the progress ofincubation.

Fifteen days presubmergence caused a decrease in the percent recovery ofapplied Cu in both the soils, the magnitude being maximum at 1st day afterincubation. Presubmergence caused about 62 and 24% increase in amorphousiron (Fe)-oxides and 1.66 and 2.3 unit rise in pH in S, and S2 soils, respectively.Increase in both amorphous Fe-oxides and pH increased the adsorptive capacityand strength of adsorption of Cu by soils which might have removed most of theCu from solution and exchangeable fraction. Such effect of presubmergence,however, disappeared after 15 days of incubation. Application of organic matterdid not cause significant change in the recovery of applied Cu in WSEX fractionthroughout the period of incubation.

Organically Complexed Fraction (OC)

With the progress of incubation, the recovery of applied Cu in this fractiondecreased marginally in S, soil, but remained almost unchanged in S2 soil.Recovery of applied Cu was higher in presubmergence treatment particularly inS2 soil throughout the period of incubation as compared to no presubmergencecontrols. Incomplete oxidation of soil organic matter during presubmergencemight have caused production of acidic functional groups having chelatingproperties (Stevenson, 1967). Also, an increase in pH during presubmergencemight have also favored complexation of Cu with organic matter (Schnitzer and

TABLE 1. Effect of presubmergence and organic matter application on the recovery of applied Cu in different fractionsduring submergence.

Presub-mergence

S, soilOday

15 days

S7 soilOday

15 days

S, soilOday

15 days

S7 SoilOday

15 days

Starch

0%0.5%0%0.5%

0%0.5%0%0.5%

0%0.5%0%0.5%

0%0.5%0%0.5%

Davs of incubation1 15 30 60

% Recoverv in WSEX8.8"7.4"1*0.8*

22.6"21.8"

1.4*1*

2*0.6*0.2'Tr.'

0.8*0.2'0.4'1.6*

1*2.8'2'3*

0.4*0.2*2.4*2.2*

2.6*2.6*3*2.8'

2.2'2"4.6*4.8*

% Recoverv in CRYOX Cu2.2*Tr*5.6*5.2*

10.8*10.8'9.4*7.4*

5.4*5*2.8*2*

7.2*5.8*6.2*2.6*

4"3.4*2'1.8'

7'2.2*4.4'3'

2*1*3'2.4*

4.8*1.4*3.2'1'

Davs of incubation1

%59.6"58"53.2*52.6*

36.2*37.8*42.2b

40.4*

15 30 60i Recoverv in OC-Cu

52.8b

40.4'55"52b

35.6*34.2*44b

41.6b

% Recoverv i2.8*0.6*3*1.6*

1.6*1.4'5'3*

9.4*10.4b

4.4'4.4'

6.8'8.6*9.2*6'

50*»45.8*52.2b

51.6*

32.6'37.2*41.6b

41.2b

46.2*49*48*49.6*

31.2*36*41b

43.8b

n RESID Cu15.2b

6'8'6'

14.8*16.6b

8.4'6.6*

18"10.4*9.8*7.2'

15.8b

16.6*13.2*8.4'

1Davs of incubatior

15% Recoverv i

26.6'34b

37.21*39.8C

28.8'28.2'42"48.2C

30.4*43.6C

37.6b

41.6C

49.6b

51.2b

40.2*48.2b

30i

60in AMOX-Cu

29.8*42C

35.8b

37.61*

45.2*43.8*43.2*47*

31.2*37b

36.2b

38b

46b

44»38*42*

I

REDISTRIBUTION OF COPPER IN ALFISOLS. II 1125

Skinner, 1966). Such increasing effect of presubmergence on recovery of appliedCu attained maximum at 15th day of incubation. No significant change wasobserved on the recovery of applied Cu in both the soils due to application oforganic matter.

Amorphous Oxides Bound Fraction (AMOX)

Recovery of applied Cu in AMOX fraction was maximum at 15th day ofincubation in both the soils and thereafter, showed a declining trend. Increasedrecovery after 15 days was due to increase in amorphous Fe-oxides content in thesoils (Saha and Mandai, 2000).

Presubmergence caused, on an average, an increase in the recovery of appliedCu in this fractions. This was probably related to the increased pH and amorphousFe-oxides content which might have retained higher amount of Cu through surfacecomplexation. Such increasing effect of presubmergence continued throughoutthe period of incubation in S, soil, but only at 1st day in S2 soil. Recovery ofapplied Cu in this fraction in general increased due to organic matter applicationin both soils. Such effect was related to increase in amorphous Fe-oxides content.

Crystalline Oxides Bound Fraction (CRYOX)

Recovery recorded gradual decrease with the progress of incubation period,particularly in S2 soil. This may be attributed to the dissolution of crystalline Fe-oxides resulting in reduced surface area for adsorption of applied Cu onto them(Saha and Mandai, 2000). Presubmergence and organic matter application didnot cause any significant change in this fraction of Cu content.

Residual Fraction (RESID)

Recovery of applied Cu in residual fraction increased gradually with the periodof submergence in both soils. Such increase was probably due to its precipitationas hydroxides, hydroxy-carbonates or sulphides.

Presubmergence in general resulted lower transformation of applied Cu in thisfraction during the period of incubation (except at 1 st day). When Cu was appliedin presubmerged soil, much of it immediately got transformed into OC and AMOXfractions leaving a very small amount in WSEX fraction available fortransformation into residual fraction. Application of organic matter did not haveany significant effect on the transformation of applied Cu into RESID fraction.

SUMMARY AND CONCLUSIONS

Overall results show that initially (at 1st day) 8.8, 59.6,26.6,2.2, and 2.8% ofapplied Cu in S, soil and 22.6,36.2,28.8,10.8, and 1.6% of applied Cu in S2 soilwere distributed respectively in WSEX, OC, AMOX, CRYOX, and RESID

1126 S AHA AND MANUAL

fractions. During submergence, applied Cu was mobilized mainly from WSEXand OC (in S, only) to AMOX and RESID fractions indicating its transformationinto less available pool.

When Cu was applied in 15 days presubmerged soils, more of it was distributedin OC (in S2 only) and AMOX fractions and less in WSEX fraction at 1st dayperiod. In contrast to no presubmergence treatment, Cu mobilization from/toWSEX, OC, and AMOX fractions were either slow or insignificant during periodsof submergence and net mobilization into RESID fraction was less. Rapid chemicalchanges due to imposition of anaerobic environment were almost complete during15 days period of presubmergence. Hence, Cu applied in presubmerged soil wasless subjected to the transformation processes.

Organic matter application in S, soil mobilized Cu from OC to AMOX fractionsand reduced transformation into RESID fraction during periods of incubation. InS2 soil, however, organic matter application had very little influence on thetransformation of applied Cu among different fractions. When Cu was applied inpresubmerged soils, the effect of organic matter application on the course of Cutransformation was also not significant. The study, therefore indicates that useefficiency of Cu in rice crop may be higher if applied in 15 days presubmergedsoil.

ACKNOWLEDGMENTS

Authors are grateful to Dr. L.N. Mandai for his constant interest and guidanceduring the experiment as well as providing necessary facilities for conductingexperiments.

REFERENCES

Katyal, J.C. 1977. Influence of organic matter on the chemical and electrochemicalproperties of some flooded soils. Soil Biol. Biochem. 9:259-266.

Mandai, B. and L.N. Mandai. 1990. Effect of phosphorus application on transformationof zinc fraction in soil and on the zinc nutrition of lowland rice. Plant Soil 121:115-123.

Papadopoulos, P. and D.L. Rowell. 1989. The reactions of copper and zinc with calciumcarbonate surfaces. J. Soil Sci. 40:39-48.

Saha, J.K. and B. Mandai. 1998. Effect of submergence on copper fractions in Alfisols. J.Indian Soc. Soil Sci. 46:32-36.

Saha, J.K. and B. Mandai. 2000. Redistribution of copper in Alfisols under submergence.I. Native Copper. Commun. Soil Sci. Plant Anal. 31(9&10):1111-1119.

REDISTRIBUTION OF COPPER IN ALFISOLS. II 1127

Schnitzer, M. and S.I.M. Skinner. 1966. Organometallic interactions in soils. 5. Stabilityconstants of Cu++-, Fe++-, and Zn++-fulvic acid complexes. Soil Sci. 102:361-365.

Stevenson, F.J. 1967. Organic acids in soil. pp. 119-146. In: A.D. McLaren and G.H.Paterson (eds.), Soil Biochemistry. Marcel Dekker, Inc., New York, NY.