Acta agriculturae Slovenica, 87 - 2, september 2006 str. 435 - 444 
Agrovoc descriptors: groundnuts, arachis hypogaea, crop yield, trace elements, 
micronutrient fertilizers, nutrient uptake, cobalt, rhizobium 
 
Agris category code: F01, F61 
 
COBISS Code 1.01 
 
Influence of microbial culture in combination with 
micronutrient in improving the groundnut productivity 
under alluvial soil of India  
 
Manisha BASU
1
, P. B. S. BHADORIA
1
 and S. C. MAHAPATRA
2
  
 
Received: March 26, 2006; accepted: August 18, 2006. 
Prispelo: 26. marca 2006; sprejeto: 18. avgusta 2006. 
 
 
ABSTRACT 
 
A field experiment was carried out to study the effect of cobalt, Rhizobium and 
phosphobacterium inoculations on growth, yield and nutrient uptake of summer groundnut in 
an alluvial soil at three levels of cobalt viz., zero, 0.21 kg and 0.42 kg ha
-1
 with four levels of 
inoculations viz., uninoculation, inoculation with Rhizobium, inoculation with 
phosphobacterium and inoculation with both Rhizobium and phosphobacterium. Results 
indicated that combined application of Rhizobium and phosphobacterium inoculation 
promoted higher dry matter production, pod yield, oil content and nutrient uptake as 
compared to application of either of the inoculations. Cobalt @ 0.21 kg ha
-1
 proved to be 
better to other doses of cobalt. The percent increase in pod yield of different treatment 
combinations over untreated control varied from, 2.4% with no inoculation + cobalt @ 0.42 kg 
ha
-1
 to 35.6% with Rhizobium + phosphobacterium + cobalt @ 0.21 kg ha
-1
. The uptake of N, 
P and K by groundnut was significantly higher in the treatments receiving both inoculation and 
cobalt at 0.21 kg ha
-1 
than sole application of either inoculation or cobalt.  
 
Key Words: Groundnut, cobalt, Rhizobium, phosphobacterium,  nutrient uptake.  
 
 
IZVLEČEK 
 
VPLIV MIKROBNE KULTURE IN MIKROHRANIL NA IZBOLJŠANJE PRIDELOVANJA 
ZEMELJSKIH OREŠKOV NA ALUVIJALNIH TLEH V INDIJI  
 
Poljski poskus je bil izveden, da bi raziskali vpliv kobalta, Rhizobium-a in fosfornih bakterij na 
rast, pridelek in privzem hranil zemeljskih oreškov, pridelanih na aluvijalnih tleh, s tremi nivoji 
gnojenja s kobaltom (brez, 0,21 kg in 0,42 kg ha
-1
 ) in štirimi različnimi inokulacijami (kontrola, 
inokulacija z Rhizobium-om, inokulacija s fosfornimi bakterijami in kombinirana inokulacija z 
obojim). Rezultati kažejo, da kombinirana inokulacija najbolj vpliva na povečanje pridelka 
sušine, pridelek strokov, vsebnost olja in privzem hranil. Odmerek gnojenja s 0.21 kg ha
-1
 
kobalta je bil optimalen. Privzem N, P in K je bil pri zemeljskih oreških značilno večji pri 
                                                 
1
 
 
Department of Agricultural and Food Engineering,
 
Corresponding author: Tele: +91 
9732654642; Fax: +91 3222255303 E-mail: manishabckv@gmail.com 
2
 
 
Rural Development Centre, Indian Institute of Technology, Kharagpur-721 302, West 
Bengal, India 

Acta agriculturae Slovenica, 87 - 2, september 2006 
 
436 
kombinirani inokulaciji ter pri odmerku 0.21 kg ha
-1 
kobalta v primerjavi z drugimi 
kombinacijami tretiranj.  
 
Ključne besede: zemeljski oreški, kobalt, Rhizobium, fosforne bakterije, privzem hranil 
 
 
 
1 INTRODUCTION 
 
Among all the oilseed crops, groundnut (Arachis hypogaea L.) has the first place in 
India accounting for more than 28% acreage and 32% production in the country 
(Anonymous, 2004). Although the country is steadily progressing in oilseeds 
production, but the average yields of most oilseeds are still extremely low when 
compared to those prevailing in other countries of the world. This is because oilseeds 
are cultivated mostly in marginal and sub-marginal land of semi-arid areas under 
unirrigated condition, hence remain vulnerable to vagaries of nature. Beneficial 
effects of Rhizobium inoculation has been observed by several workers (Naidu, 2000) 
who reported an increase in yield and oil content of groundnut with such inoculation. 
Phosphorus deficiency is probably the major limitation to the growth of legumes in 
many soils. Phosphobacterium, an organism turning the phosphate present in the soil 
from unavailable to available form, has an indirect but definite effect on the 
nodulation and yield of groundnut. The seed and soil inoculations with 
phosphobacterium inoculants can significantly increased the pod yield of groundnut 
(Balasubramanian and Palaniappan, 1994) as compared to no inoculation. Along with 
other micronutrients like Mo, Zn, B, Co also takes an important place for nitrogen 
fixation in the legumes and in the root nodules of non-legumes. Cobalt application 
increases the formation of leghaemoglobin required for nitrogen fixation thereby 
improves the nodule number per plant and ultimately pod yield of groundnut (Yadav 
and Khanna, 1988).  Three specific cobalamine dependent enzyme systems in 
Rhizobium which may account for the influence of cobalt on nodulation and nitrogen 
fixation are: methionine synthase, ribonucleotide reductase and methylmalonyl co-
enzyme A mutase (Das, 2000).  
 
The aim of the present experiment is to evaluate the effect of Rhizobium, 
phosphobacterium and cobalt on yield, oil content and nutrient uptake of groundnut 
under field condition. 
 
 
2 MATERIALS AND METHODS 
 
Field experiment was conducted for two years (2001-2002) with groundnut (Arachis 
hypogaea Linn) variety, JL-24 in the pre-kharif season (Feb-June) in the alluvial soil of 
eastern part of West Bengal, India. The soil characteristics of the experimental site was sandy 
clay loam with neutral pH (7.2). The organic carbon, available N, P, K and Co content was 
0.66%, 109.5 ppm, 22.4 ppm, 85.3 ppm and 0.03 ppm, respectively. The weather of the 
experimental site was warm and humid with average maximum temperature of 32.7 ± 1.57
0
C, 
minimum temperature of 22.8 ± 2.54
0
C, average rainfall of 117.6 ± 96.8 mm, maximum 
relative humidity of 94.6 ± 3.08% and minimum relative humidity of 63.7 ± 14.6%.  The 
experiment was laid out with two factors, i. e., inoculation with Rhizobium (I
R
) (strain: M 10),  
inoculation with phosphobacterium (I
P
) (Bacillus polymyxa), inoculation with both Rhizobium 
and phosphobacterium and uninoculation (I
0
) and three levels of cobalt viz., no cobalt, 0.21 
kg and 0.42 kg cobalt ha
-1
 designated as C
0
, C
.21 
and C
.42 
respectively. Inoculations were 

BASU, M. et al.: Influence of microbial culture in combination with micronutrient …  
 
437
allotted to main plots and levels of cobalt to the sub plots under each main plot. Thus, 12 
treatments were arranged in a split plot design with three replications.  
 
2.1 Analysis of soil and plant 
  
Soil samples were collected from the experimental site before and after the experiment to 
know the fertility status of the soil. Processed samples were analyzed for different 
physicochemical properties of soil viz., pH, organic carbon, available nitrogen, available 
phosphorus and available potassium by following standard procedures (Jackson, 1973). 
Cobalt was estimated by DTPA extraction method (Lindsay and Norvell, 1978).  
 
Haulms of groundnut were dried at 72
o
C for 48 hours in oven, ground and subsequently used 
for its chemical analysis. The total N and P was determined by modified Kjeldahl method and 
vanado-molybdate blue color method respectively (Chapman and Pratt, 1961). K and Co was 
determined by following the wet digestion method (Jackson, 1973).  
 
2.2 Statistical analysis 
  
The data were analyzed statistically by applying analysis of variance for split plot design. 
Least significant differences (LSD) were conducted at a 5% level of probability (Gomez and 
Gomez, 1976). 
 
 
3 RESULTS AND DISCUSSION 
 
3.1 Growth parameters 
 
Table 1 and Figure 1 shows that there was a significant influence of different 
treatments of inoculation and cobalt on the plant height, number of branches per plant 
and dry matter production at harvest and leaf area index (LAI), number of nodules per 
plant at 50 days after sowing (DAS) of groundnut. Combined application of 
Rhizobium and phosphobacterium inoculation was better as compared to use of either 
of the inoculation at a given dose of cobalt. These parameters were also significantly 
influenced by different levels of cobalt. The highest dry matter production in 
application of both Rhizobium and phosphobacterium was due to the fact that it 
produced maximum shoot length, higher number of branches per plant and leaf area 
index (LAI) (Chetti et al., 1995; Naidu, 2000). The maximum values were found with 
Co @ 0.21 kg ha
-1
 followed by Co @ 0.42 kg ha
-1
. The minimum values of all the 
growth parameters observed in case of without cobalt application. Increase in dry 
matter production due to cobalt application has been reported by Joshi et al. (1987). 
The combination of Rhizobium inoculation, phosphobacterium inoculation and cobalt 
at lower dose (@ 0.21 kg ha
-1
) proved superior to any other combinations of 
inoculation and cobalt. There was no significant difference between Rhizobium 
inoculation and phosphobacterium inoculation. 

Acta agriculturae Slovenica, 87 - 2, september 2006 
 
438 
460
480
500
520
540
560
580
600
Dry matter accumulation 
(g m-2)
I0C0   
I0C.21
I0C.42  
IRC0
IRC.21
IRC.42  
IPC0
IPC.21
IPC.42  
IP+RC0
IP+RC.21
IP+RC.42  
Treatments
 
(Note: I
0
=No inoculation,
 
I
R
=Inoculation with Rhizobium and I
P
=Inoculation with Phosphobacterium. 
C
0,
 C.
21,
 C
.42 
= Cobalt @ zero, 0.21 and 0.42 kg ha
-1
 respectively.) 
 
Fig. 1: Dry matter accumulation by groundnut at harvest as influenced by different levels of 
inoculations and cobalt (Pooled mean of two years).  
 
 
3.2 Pod yield, haulm yield and oil percent  
 
There was a significant influence of different treatments of inoculations and cobalt on 
pod yield, haulm yield and oil percent of groundnut (Table 2). Pod yield in all the 
treatment combinations were significantly higher than the untreated control. Again 
pod yield, averaged across three levels of cobalt, was recorded to be highest for 
inoculation with both Rhizobium and phosphobacterium, which was 19.7% and higher 
over no inoculation. Beneficial role of Rhizobium in the N nutrition through 
nodulation and a consequently better growth or development attributed for this yield 
advantage 
 
 (Subramaniyan and Kalaiselven, 2000). In general, average (across three 
inoculations) pod yield of groundnut was about 14.5% higher with Co @ 0.21 kg ha
-1 
than without cobalt. However, increasing the level of cobalt to 0.42 kg ha
-1 
did not 
significantly influence the pod yield. Lower dose of cobalt helps in better nodulation 
and consequently a better growth and yield, but at a higher level cobalt reduced the 
bacterial population in the rhizosphere and as a result nodulation was hampered which 
led to a lower growth and yield of the crop (Jana and Sounda, 1994). Application of 
both Rhizobium and phosphobacterium inoculation along with cobalt at 0.21 kg ha
-1
 
showed 35.6% higher pod yield than untreated control. Balamurugan and 
Gunasekaran (1996) reported that the combined inoculation of Rhizobium and 
phosphobacterium gave maximum crop growth, nodulation and yield in groundnut. 
Similar trend was followed in case of haulm yield. As in pod yield different levels of 
inoculations and cobalt significantly influenced oil percent. Average oil percent 
increased by about 12.4% over without cobalt and enhancing the cobalt level beyond 
0.21 kg ha
-1
, 
did not significantly increase the oil percent. Combined application of 
Rhizobium inoculation, phosphobacterium inoculation and Co @ 0.21 kg ha
-1
 gave 
higher values than single application of either inoculation or cobalt. Similar 
observations were reported by Raj and Rao (1996).  
 
 

BASU, M. et al.: Influence of microbial culture in combination with micronutrient …  
 
439
Table 1:  Growth parameters of groundnut as influenced by cobalt and inoculations 
(Pooled mean of 2001-2002) 
 
Treatment 
combinations  
Plant height 
(cm) 
Number of 
branches plant
-1
 
LAI
1
  
1
Number of 
nodules plant
-1
 
I
0
C
0
                45.7 9.5 2.58 146.4 
I
0
C
.21
 50.8 11.4 3.17 155.0 
I
0
C
.42
                             46.9 9.7 2.95 151.7 
I
R
C
0
 52.8 11.4 3.01 181.3 
I
R
C
.21
 60.2 14.0 3.70 193.2 
I
R
C
.42
         55.0 11.5 3.41 189.9 
I
P
C
0
  52.5 10.8 3.01 157.7 
I
P
C
.21
 58.4 13.4 3.72 172.7 
I
P
C
.42
                54.1 11.1 3.51 166.3 
I
P+R
C
0
  55.1 11.8 3.22 190.2 
I
P+R
C
.21
 61.3 14.9 3.85 214.8 
I
P+R
C
.42
                55.2 11.6 3.67 198.5 
LSD (P=0.05) 
At same inoculation 4.23 1.23 0.57 7.83 
At same cobalt level 1.68 NS NS 6.01 
Inoculation X Cobalt 
interaction 7.08 3.02 1.07 9.93 
 (LAI and number of nodules plant
-1
 at 50 DAS; I
0
=No inoculation,
 
I
R
=Inoculation with Rhizobium and 
I
P
=Inoculation with Phosphobacterium. C
0,
 C.
21,
 C
.42 
= Cobalt @ zero, 0.21 and 0.42 kg ha
-1
 
respectively. LSD: Least significant difference) 
 
3.3 Nutrient uptake 
 
Levels of inoculation and cobalt significantly influenced the total uptake of N, P, K 
and Co by groundnut at harvest (Table 3). Rhizobium inoculation recorded 5.48% 
higher N uptake over phosphobacterium inoculation. The beneficia l e f f e c t o f 
Rhizobium was also observed by Saad et al. (1998) and Naidu (2000). Average N 
uptake (across three cobalt value) was maximum in combined application of 
Rhizobium and phosphobacterium inoculation as compared to single application of 
either of the inoculations and it was 22.6% and 29.33% higher over Rhizobium and 
phosphobacterium inoculation respectively. Shasidhara and Sreenivasa (1994) 
obtained the same results. On an average, the average value of N uptake (across three 
inoculation levels) increased when cobalt was applied @ 0.21 kg ha
-1
 and enhancing 
the cobalt level to 0.42 kg ha
-1
, 
had no positive effect. The maximum N uptake value 
was obtained with Rhizobium + phosphobacterium inoculation + Co @ 0.21 kg ha
-1
 
which was followed by Rhizobium inoculation + Co @ 0.21 kg ha
-1
 and the difference 
was 27.4%. The cause of maximum uptake of N in combined application of 
Rhizobium and phosphobacterium inoculation with cobalt @ 0.21 kg ha
-1
 was that, it 
had increased the population of nitrogen fixing bacteria (Rhizobium) in the 
rhizosphere which led to more infection as well as nodule formation (Yadav and 
Khanna 1988). Phosphorus uptake also followed the same trend as N. Groundnut 
inoculated with Rhizobium + phosphobacterium culture resulted in 29.4% and 31.6% 
higher average P uptake over application of either Rhizobium inoculation or 
phosphobacterium inoculation respectively. But there was no significant difference 
between P uptake at Rhizobium and phosphobacterium inoculation. Cobalt applied @ 
0.21 kg ha
-1
 significantly increased the average P uptake over without cobalt; the 
extent of increase was about 21.0%. The maximum value was obtained with 

Acta agriculturae Slovenica, 87 - 2, september 2006 
 
440 
Rhizobium + phosphobacterium + cobalt @ 0.21 kg ha
-1
. Similar observations 
regarding the effect of inoculation and cobalt on nutrient uptake were also reported by 
and Raj and Rao (1996). Uptake of K also followed the similar trend as N and P. The 
uptake of cobalt was higher with phosphobacterium inoculation than Rhizobium 
inoculation and the difference was 28.2%. Maximum uptake of cobalt was found in 
use of both the inoculation along with Co @ 0.42 kg ha
-1
 followed by 
phosphobacterium + cobalt at @ 0.42 kg ha
-1
.  
 
Table 2: Pod yield, haulm yield, oil content and protein content of groundnut as 
influenced by cobalt and inoculations (Pooled mean of 2001-2002) 
 
Treatment 
combinations  
Pod yield (kg 
ha
-1
) 
Haulm yield 
(kg ha
-1
) 
Oil content 
 (%) 
Protein content 
 (%) 
I
0
C
0
                1701.6 2603.6 42.9 20.2 
I
0
C
.21
 1810.4 3302.3 47.5 28.9 
I
0
C
.42
                             1742.4 3042.6 45.7 27.3 
I
R
C
0
 1888.8 3809.8 45.9 33.2 
I
R
C
.21
 2158.6 4148.8 48.7 35.1 
I
R
C
.42
         1954.8 3967.8 47.6 34.6 
I
P
C
0
  1868.9 3759.2 45.8 30.9 
I
P
C
.21
 2166.1 4125.2 48.8 32.9 
I
P
C
.42
                1982.0 3973.6 47.0 31.7 
I
P+R
C
0
  1914.6 3875.2 46.2 32 
I
P+R
C
.21
 2307.3 4305.4 49.8 33.8 
I
P+R
C
.42
                2065.3 4056.2 47.3 32.6 
LSD (P=0.05) 
At same inoculation 
109.95 619.77 1.73 5.42 
At same cobalt level 70.64 155.60 1.48 2.66 
Inoculation X Cobalt 
interaction 
205.86 700.98 2.56 5.59 
Note: I
0
=No inoculation,
 
I
R
=Inoculation with Rhizobium and I
P
=Inoculation with Phosphobacterium. 
C
0,
 C.
21,
 C
.42 
= Cobalt @ zero, 0.21 and 0.42 kg ha
-1
 respectively., LSD: Least significant difference. 
 
3.4 Residual soil fertility 
 
The data on changes in nutrient content of soil over two years (Figure 2) revealed that 
there was a marginal change under the influence of different inoculations and cobalt 
levels. After two years the nitrogen content of the soil increased from an initial value 
of 110 ppm to as high as 150 ppm under combined application of Rhizobium and 
phosphobacterium inoculation. The build-up of P was also greater in application of 
both Rhizobium and phosphobacterium with an increment in average phosphorus 
content of  the soil up to 32 ppm. Cobalt application improved the cobalt 
accumulation in soil. Increasing the dose of cobalt subsequently increased the cobalt 
content of the soil with a maximum value of 0.38 ppm. Improvement of the cobalt 
content of the soil was higher in association with phosphobacterium inoculation than 
in combination with Rhizobium inoculation.  
 
 
 

BASU, M. et al.: Influence of microbial culture in combination with micronutrient …  
 
441
Table 3: Nutrient uptake by groundnut as influenced by cobalt and inoculations 
(Pooled mean of 2001-2002) 
 
Nutrient Uptake  
kg ha
-1
 g h a
-1
 
Treatment 
Combinations 
N P K Co 
I
0
C
0
               96.3 10.4 16.3 4.3 
I
0
C
.21
 103.6 12.6 19.1 7.1 
I
0
C
.42
                            99.1 11.3 17.6 5.6 
I
R
C
0
 120.3 16.2 20.5 8.2 
I
R
C
.21
 135.2 19.9 26.5 12.3 
I
R
C
.42
        125.4 17.9 22.9 10.5 
I
P
C
0
 111.1 16.1 21.4 11.3 
I
P
C
.21
 129.2 19.3 24.2 14.9 
I
P
C
.42
               120.5 17.7 23.4 13.4 
I
P+R
C
0
 140.5 21.5 24.4 14.1 
I
P+R
C
.21
 172.2 26 30.5 19.3 
I
P+R
C
.42
               153.9 22.3 25.5 16.2 
LSD (P=0.05) 
At same inoculation 
11.31 4.49 2.13 5.61 
At same cobalt level 8.06 2.51 1.85 2.64 
Inoculation X Cobalt interaction 25.11 4.87 5.99 2.21 
Note: I
0
=No inoculation,
 
I
R
=Inoculation with Rhizobium and I
P
=Inoculation with Phosphobacterium. 
C
0,
 C.
21,
 C
.42 
= Cobalt @ zero, 0.21 and 0.42 kg ha
-1
 respectively. LSD: Least significant difference 
 
 
3 CONCLUSIONS 
 
It could reasonably be said that the combined application of Rhizobium and 
phosphobacterium inoculation increased the yield and nutrient uptake of groundnut as 
compared to no inoculation or application of either of the two inoculation. Lower 
dose of cobalt (0.21 kg ha
-1
) resulted in maximum benefit towards crop yield as 
compared to the higher dose. It could reasonably be said that the combined 
application of Rhizobium culture, phosphobacterium with lower dose of cobalt (0.21 
kg ha
-1
) resulted in maximum benefit towards crop yield as compared to the combined 
application of phosphobacterium inoculation and cobalt or single application of either 
inculation or cobalt. Besides the yield advantage, positive residual soil chemical 
properties in terms of available N, P, K and Co were also noted in the soil under the 
combined application of inoculations and cobalt as compared to sole application of 
only inoculation or cobalt.  

Acta agriculturae Slovenica, 87 - 2, september 2006 
 
442 
95.0
105.0
115.0
125.0
135.0
145.0
155.0
Content, ppm
I0C0   
I0C.21
I0C.42  
IRC0
IRC.21
IRC.42  
IPC0
IPC.21
IPC.42  
IP+RC0
IP+RC.21
IP+RC.42  
Treatments
Nitrogen
 
17.0
19.0
21.0
23.0
25.0
27.0
29.0
31.0
33.0
Content, ppm
I0C0    
I0C.21
I0C.42    
IRC0
IRC.21
IRC.42    
IPC0
IPC.2 1
IPC.42    
IP+RC0
IP+RC.21
IP+RC.42    
Treatments
Phosphorus
 
(Note: I
0
=No inoculation,
 
I
R
=Inoculation with Rhizobium and I
P
=Inoculation with Phosphobacterium. 
C
0,
 C
1,
 C
2 
= Cobalt @ zero, 0.21 and 0.42 kg ha
-1
 respectively.) 
 
Fig. 2: Effect of different levels of cobalt and inoculations on N and P content of soil 
after two years.  
 
 

BASU, M. et al.: Influence of microbial culture in combination with micronutrient …  
 
443
 
 
80.0
85.0
90.0
95.0
100.0
Content, ppm
I0C0    
I0C.21
I0C.42    
IRC0
IRC.21
IRC.42    
IPC0
IPC.2 1
IPC.42    
IP+RC0
IP+RC.21
IP+RC.42    
Treatments
P o ta ssi u m
 
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
Content, ppm
I0C0    
I0C.21
I0C.42    
IRC0
IRC.21
IRC.42    
IPC0
IPC.21
IPC.42    
IP+RC0
IP+RC.21
IP+RC.42    
Treatments
Cobalt
 
(Note: I
0
=No inoculation,
 
I
R
=Inoculation with Rhizobium and I
P
=Inoculation with Phosphobacterium. 
C
0,
 C
1,
 C
2 
= Cobalt @ zero, 0.21 and 0.42 kg ha
-1
 respectively.) 
 
Fig. 3: Effect of different levels of cobalt and inoculations on K and Co content of soil 
after two years. 
 
 
4 LITERATURE 
 
Anonymous, 2004. Agricultural Statistics at a Glance. Ministry of Agriculture. Govt. of India. 
Balamurugan, S., Gunasekaran, S. 1996. Effect of combined inoculation of Rhizobium sp. and 
phosphobacteria at different levels of phosphorus in groundnut. Madras Agricultural 
Journal, 83 (9): 503-505.  
Balasubramanian, P., S. Palaniappan. 1994. Effect of combined application of bacterial 
inoculation along with farmyard manure on irrigated groundnut (Arachis hypogaea 
L.). Ind. J. Agron. 39(1): 131-133.  
Chapman, H.D. and P.F. Pratt. 1961. Method for analysis of soil, plant and waters. Univ. of 
California, USA. 
Chetti M. B., E. Antony, U. V. Mummigatti, M. B. Dodamani. 1995. Role of nitrogen and 
Rhizobium on nitrogen utilization efficiency and productivity potential in groundnut 
genotypes. Farming Systems. 11(1-2): 209-216. 
Das, D. K. 2000. Micronutrients: Their Behaviour in Soil and Plants. Kalyani Publishers, UP, 
India. 

Acta agriculturae Slovenica, 87 - 2, september 2006 
 
444 
Jackson, M. L. 1973. Soil Chemical Analysis. Prentice Hall of India Pvt. Ltd., New Delhi. 
Jana, P. K., G. Sounda. 1994. Effect of cobalt and Rhizobium on yield, oil content and 
nutrient concentration in irrigated summer groundnut (Arachis hypogaea L). Ind. J. 
Agric. Sci. 64(9): 630-632.  
Joshi, P. K., D. M. Bhatt, J. H. Kulkarni. 1987. Groundnut root nodulation as effected by 
micronutrients application and Rhizobium inoculation. Int. J. Tropic. Agric. 5(3-4): 
199-202. 
Lindsay, W.L. and W.A. Norvell.1978. development of a DTPA soil test for zinc. iron, 
manganese and copper. Soil Sci. Soc. Am. J. 42: 421-428. 
Naidu, P. H. 2000. Response of bunch varieties of groundnut to Rhizobium inoculation. Leg. 
Res. 23(2): 130-132. 
Raj, A. K., D. S. R. M. Rao. 1996. Effect of Rhizobium inoculation, nitrogen and phosphorus 
application on yield and yield attributes of groundnut. Leg. Res. 19(3-4): 151-154.  
Saad, O. A. O., M. A. O. Mohandes. 1998. Effect of inoculation with immobilized or free 
genetically engineered Bradyrhizobium arachis on nodulation and growth 
characteristics of groundnut.  Arab Univ. J. Agric. Sci. 6(2): 329-341. 
Shasidhara, G.B. and M. N. Sreenivasa. 1994. Response of groundnut to the inoculation of 
VA-mycorrhizal fungi and/or Rhizobium in vertisols. J. Maharastra Agric. Univ. 
9(3): 464-465.  
Subramaniyan, K., P. Kalaiselven. 2000. Evaluation of different Rhizobium Strains for 
groundnut (Arachis hypogaea L). Res. on Crops. 1 (2): 156-158.  
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