EFFECT OF COPPER LEVELS ON COPPER CONTENT IN SOIL NUTRIENT UPTAKE AND YIELD OF SOYBEAN (GLYCINE MAX) VARIETIES

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1 Legume Res., 29 (4) : , 2006 EFFECT OF COPPER LEVELS ON COPPER CONTENT IN SOIL NUTRIENT UPTAKE AND YIELD OF SOYBEAN (GLYCINE MAX) VARIETIES K.C. Barik- and A.S. Chandel Department of Agronomy, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar , India ABSTRACT Experiments were conducted during 1997 and 1998 to study the effect of different levels of copper on soil copper content and Its nutritional effect on the uptake of nitrogen, phosphorus and potassium by different varieties ofsoybean (Glycine max L.MerriU). Results revealed that application of copperconsistently Increased thedifferent forms of copper In soil viz., M DTPA-ilXtractabie copper, fixed copper and total copper and were positively and significantly correlated with each other. Soybean varieties differed significantly In their copper requirement for grain yield, grain nitrogen, phosphors and potassium uptake. Variety PK 416 at 5kg Cu/ha showed a trend of increased grain yield nutrient uptake, whereas yielded lowest could be grown on copper defldent soils while or PK 262 gave Intermediate response at 2.5 kg Cu/ha. INTRODUCTION having ph 7.2,. contained organic carbon Soybean (Glycine max L. Merrill) has per cent, available mineralizable already emerged as one of the major rainy nitrogen 325 kg N/ha, phosphorus (Olsen's season cash crop in India and its cultivation is P) 10.5 kg P/ha, potassium, 132 kg K/haand fast spreading. Since, the discovery of the 0.87 mg/kg soil 0.005M DTPA-extractable essentiality of copper for nutrition of higher copper' respectively. Sixteen treatments plants, significant advances in our combinations comprising 4 varieties (, understanding of the behaviour of copper in PK 262, PK 416 and ) as main plot soil and plants have been made. Barik and treatments and 4 copper levels (0,2.5,5 and Chandel (2001) reported that soybean varieties 10 kg Cu/ha) as sub-plot treatments were differed in their copper requirement for tested in split-plot design with 3 replications. growth, grain yield and copper uptake. $oybean varieties were inoculated at the rate However, there is paucity of information on of 2.5 g of fresh Bradyrhizobium japonicum the effect of cropperapplication on the status culture per kg of seeds. Copper was applied of available (0.005 MDTPA-extractable), fixed as CuSO4' 5 H 2 0 before sowing and and total copper in soil at different growth thoroughly mixed in 0-15cm soil layer. To study stages of soybean and their nutritional effect the change of applied copper in soil, soil on I the uptake of nitrogen, phosphorus and samples at 30,60,90 days after sowing and at potassium by different varieties of soybean. harvest of soybean were analysed for different Therefore, the present field experimentation forms of copper viz., M DTPA was conducted to elucidate information on extractable copper, total copper and fixed these aspect. copper (refer to amount of copper which is MATERIAL AND METHODS non-extractable by M DTPA-extractable The field experiment was conducted copper). The nitrogen, phosphorus and during the rainy season of 1997 and 1998at potassium content in soybean grain at harvest Crop Research Centre, Pantnagar. The were determined and the uptake of the experimental soil is fertile belongs to mollisols, nutrients were calculated by multiplying the Department of Agronomy, OUAT, Bhubaneswar ,lndia.

2 Vol. 29, No.4, percentage of nutrient with grain yield and dividing by 100. RESULTS AND DISCUSSION Effect on soil copper content Varietal differences and effects of applied copper levels on available copper (0.005 M DTPA extractable) in soil was found significant at all growth stages of soybean (Table 1). The maximum extractable copper was available where was grown which was significantly higher than other varieties and minimum was found with. Thus, depleted minimum and maximum available copper and caused significant changes in the available copper content in the soil. Because soybean varieties dependent upon atmospheric fixed nitrogen and probably H+ -ion activity in their rhizospheric microenvironment resulted substantial changesin bi~avaiiabiuty ofcopper in soil. Summer et aj. (1992) in soybean also reported similar variations in available copper in soil due to varietal rhizosphere sensitivity. Application of copper resulted consistent increase in available copper and maximum value was recorded with 10 kg Culha and compared to control an increase of 100, 309 and 439 percent of Cuwasavailable with the application of 2.5, 5 and 10 kg Culhas at 30 days after sowing and it progressively decreased to 51.8,249.3 and per cent at harvest respectively. This general trend of greateravailability of copper in 0-15 em depth of surface soil layer is due to higher rate of copper application and the decrease in available copper with time increased with the amount of copperapplied at sowing. The fixed copper content increases with crop age and it was always higher where wasgrown. Application of copper also caused consistent increase in fixed copper content in soil and compared to control it increase 3.11, 6.20 and per cent with the application of 2.5, 5 and 10 kg Culha, respectively. Thus, maximum amount of fixed copper was found with 10 kg Culha at all growth stages which were significantly higherthan 'control, 2.5 and 5 kg Cu/ha. The experimental soil have iilitic minerals and were relatively rich in organic matter and therefore, much of copper applied might have complexed with organic matter contributing to fixed copper fraction. The differences in total copper content insoil due to varieties were non-significant. Application of copper resulted significant increase in total copper content of soil and it increased with increasing rates of copper application. Application of 10 kg Culha resulted highest total copper content in soil at all growth stages which was significantly higher than that of its lower doses. The correlation studies (Table 2) among different forms of copper revealed that there was positive and highly significant (P~O.OI) correlation exists between available copper, fixed copper and total copper in soil. Higher order of this positive significant correlation between these forms of copper showed the dynamic interchangeable relationship between these fractions of copper in soil. Effect on nutrient content and uptake The differences due to varieties, copper level and their interactioneffect (Table 3) were significant for nitrogen, phosphorus and potassium uptake in grain. accumulated significantly less nitrogen in grain. Copper application at the rate of 2.5 kg Cui ha significantly increased grain nitrogen content over control and 2.5 kg Cu/ha respectively. Variety PK 416 and PK 262 both had significantly higher nitrogen in grain than either or. Nitrogen uptake in grain was significantly highest in variety PK 416 compared to other varieties. Nitrogen uptake in grain showed a significant increase upto 5 kg Cu/ha resulting 16.4 per cent increase over the control but the difference between 2.5 and 5 kg Cu/ha was non-

3 254 LEGUME RESEARCH Table 1. Effect of copper application on different forms of copper In soil (pooled data of 1997 and 1998) at different growth stages of soybean varieties Treatments M DTPA extractable copper Total copper (ppm) Axed copper (ppm) 30 DAS 60 DAS 90 DAS Harvest 30DAS 60DAS 90DAS tfajwst 30DAS 60DAS 90DAS Harvest PK PKI co (P-0.05) NS NS NS NS NS NS Copper levels (kg CuIha) co (P-0.05) NS= non-signlficant; DASa Days after sowing. Crop growth stage Table 2. interrelationship between different forms of copper In soil Correlation coefficient (r) among different forms of copper In soil Between 0.005M Between M Between total and DTPA-extractable DTPA-extractable fixed copper copper and total copper copper and fixed copper 30 DAS 0.979** 0.945" 60 DAS DAS At harvest 0.985" Significant at one per cent probability. significant. The interaction effect showed that PK 416 at 5 kg Cu/ha gave higher grain nitrogen uptake than the remaining other varieties compared at same ordifferent copper levels. The results showed that copper application increased the nitrogen content in soybean grain which might be due to the effect of copper on increased nodulation and the increase in nitrogen uptake was mainly due to increase in nitrogen content and grain yield confirming the findings of Seliga (1993) in Lupinus Juteus L. The differences due to varieties and copper levels were significant for phosphorus content and uptake in grain, whereas, their interaction effect was significant only for phosphorus uptake. PK 416 and PK 262 contained significantly highest and lowest in. Application of 2.5 kg Cu/ha 0.989" significantly increased 15.9 per cent phosphorus content over control, thereafter it decreased significantly with increasing copper levels ranging from 12 per cent to more than 25 per cent. Variety PK 416 gave highest phosphorus uptake. which was significantly more than that of remaining varieties. However, the differences in phosphorus uptake between or PK 262 was nonsignificant. Minimum uptake was obtained in. The phosphorus uptake was significantly increased with 2.5 kg Culha resulting 15.9 per ~nt increase over control. Interaction effect betweenvarieties and copper levels for phosphorus' uptake revealed that variety PK 416 at 5 kg Cu/ha gave maximum uptake which was significantly higher than other varieties at same or different copper levels. This confirms the earlier results of

4 Vol. 29, No.4, Table 3. Interaction effect of copper application on grain nitrogen, phosphorus and potassium uptake in different varieties of soybean (pooled data of ) o Copper levels (kg Cu/ha) GraIn Nitrogen uptake (k9/fiil) (6.17) (6.32) (6.67) (6.94) 69.21(6.26) (6.64) (6.95) (6.72) (6.40) (6.79) (6.94) (6.63) (6.11) (6.26) (6.78) (5.96) (6.24) (6.50) (6.84) (6.56) COl (p=0.05) = (0.12), CO 2 (p=0.05)=4.37 (0.07), (P=0.05)=8.75 (0.15), C0 4 (P=0.05)=12.89 (0.18) Grain Phosphorus uptake (kg/ha) 3.91 (0.36) 3.79 (0.43) 3.03 (0.32) 2.58 (0.28) 4.98 (0.45) 6.79 (0.49) 5.02 (0.42) 9.04 (0.37) 6.88 (0.42) 7.65 (0.46) 8.03 (0.44) 6.42 (0.39) 5.25 (0.41) 6.16 (0.45) 6.04 (0.43) 5.43 (0.37) (0.41) 6.10 (0.46) 5.53 (0.40) 4.62 (0.35) COl (p=0.05) = 0.72 (0.01), CO 2 (P=0.05)=0.33 (0.02), CD 3 (p=0.05)=0.67 (NS). C0 4 (P=0.05)=0.93 (NS) GraIn potassium uptake (kg/ha) (1.09) (1.18) (1.17) 98.20(1.08) (1.13) (1.18) (1.1'.i (1.21) (1.13) (1.16) (1.19) (1.13) (1.29) (1.51) (1.45) (1.36) (1.16) (1.25) (1.25) (1.19) COl (p=0.05) = 4.61 (NS), CO 2 (p=0.05)=0.% (0.51), (P=0.05)=1.92 (NS), C0 4 (p=0.05)=4.89 (NS) Figures in parenthesis indicate respective nutrient contents in per cent; COl' for comparing varieties; CO 2, for comparing copper levels;, for comparing two copper levels at same variety; C0 4, for comparing two varieties at same or different copper levels. Table 4. Effect of interaction between varieties and copper levels on grain yield (kg/ha) of soybean (pooled data oftwo yeas) (6~53) (6.64) (6.61) (6.28) 3.33 (0.35) 5.21 (0.43) 7.24 (0.43) 5.72 (0.42) (1.13) (1.18) (1.15) (1.40) Variety Grc.in yield (kg/ha) Copper levels (kg Cu/ha) o PK PK Copper levels For comparing copper levels at same variety For comparing two varieties at same or different copper levels C.O. (P=0.05) Not significant

5 256 LEGUME RESEARCH Greenwood and Hallsworth (1960) with forage legumes with direct enhancement of phosphorus content and uptake by an increased copper supply. Higher copper levels significantly decreased the phosphorus content and their uptake which might have been due to the inability of the soybean plants to utilise available phosphorus at higher copper levels. The varietal differences for potassium content was non-significant, whereas, the effects of copper levels were significant. Application of 2.5kg Cu/ha significantly increased the potassium content by 8.2 per cent over control and remained at par with 5 kg Culha. Variety PK 416 recorded maximum potassium uptake followed by and both were significantly higher than eith~ or PK 262. Application of 2.5 and 5 kg Cui ha showed a significant increase of 11.1 and 14.9 per cent grain potassium uptake over control, whereas, the differences in uptake between them was non-significant. The interaction effect showed that variety PK 416 at 5 kg Culha gave highest potassium uptake which was significantly more than that of other varieties at same or different copper levels. Antil et al., (1988) similarly obtained an increase in potassium content and uptake with the field application of copper which might be due to the stimulated effect of copper on potassium uptake. Effect on yield The soybean varieties were significantly different in grain yield (Table 4). REFERENCES Antil, R.S. et al. (1988). Indian Soc. Soil Sci., 36: Barik, K.C. and Chandel, A.S. (2001). Indian J. Agric. Sci., 71: Gartrell, J.w. (1981). Copper in Soils and Plants, pp Greenwood, E.A.N and Ha1Jsworth, E.G. (1960). Plant Soil, 12: Oplinger, E.S. and Ohlorgge, A.J. (1974). Agron. J., 66: Seliga, H. (1993). Plant Soil, 155/156: Summer, M.E. et al. (1992). J. Plant Nutrition, 2: Highest grain yield was recorded in PK 416 which was significantly greater than that of other varieties followed by. The differences in grain yield between and PK 262 are also significant. The minimum yield was recorded in. The differences is grain yield due to copper levels were nonsignificant. However, interaction effects between varieties and copper levels were significant. The pooled results showed that PK 416 produced consistently at paratall Cu levels and recorded highest grain yield at 5 kg Cui ha which was significantly higher than that of other varieties at same or different copper levels. Again, the grain yield of PK 262 at 2.5 kg Culha interestingly at par with that of PK 1042atall copper levels and were significantly higher than that of. Minimum grain yield was recorded in at all copper levels, which was significantly lower than all the varieties. The results further revealed that the experimental soil which contained about 0.87 ppm available copper may not be sufficient for varieties like PK 416 for their nutrition or their requirements might have been increased due to regular application of nitrogenous or super phosphatic fertilizers to the soil (Gartell 1981). Again, increase in grain yield in PK 416 with copper application presumably associated with higher uptake of nitrogen phosphorous and potassium (Table 3) in this study. Oplinger and Ohlrogge (1979) also reported similar increase in grain yield of soybean due to copper application in soil.