MATERIALS AND METHODS

A field trial on brinjal was conducted at HRC Farm, Joydebpur, Gazipur during the rabi seasons of 2004-2005 and 2005-2006. The soil of the experimental site was silty clay loam in texture.

Table 1:	Chemical properties of the initial soil of the experimental field at Joydebpur

The physical and chemical properties of the analysed soil sample are shown in Table 1. The treatments were laid out in a randomized block design (factorial) having replications thrice. There were sixteen treatments combinations comprising each of four levels of boron (0, 0.075, 1.50 and 2.25 kg ha^-1) and four levels of molybdenum (0, 0.075, 1.50 and 2.25 kg ha^-1). The unit plot size and plant spacing were 25x75 cm. The variety Kazla (BARI Begun-4) was taken as a test crop. Thirty days seedlings were transplanted on 27 November for both the years of 2004-2005 and 2005-2006, respectively. A combined blanket dose of N₁₅₀ P₄₅ K₁₀₀ S₂₀ kg ha^-1 and 5t CD/ha were applied before final land preparation. Nitrogen was splited into three equal installments. The 1/3rd N was applied around the plants after 15 days of planting, 2nd installment at first flower appearing stage and remaining one at fruiting stage. All necessary intercultural operations like weeding irrigation, spraying pesticides etc. were performed as and when required by the experiment. Young fruits were harvested time to time at edible stage. Five plants were randomly selected from each and every treatment for recording necessary yield data. The collected data were compiled and analysed statistically adjusted with Duncans Multiplie Range Test (DMRT) and Least Significant Difference at 5% level of significant.

RESULTS AND DISCUSSION

Effect of boron: Table 2 reflected that boron significantly influences the yield and yield attributes of brinjal. Yield and yield components of brinjal progressed in upward direction up to 1.50 kg B/ha and thereafter declined.

However, the highest plant height (95.30 and 94.30 cm), fruit size (15.49x5.80 cm and 15.54x5.36 cm) and individual fruit weight (63.52 and 91.0 g) were obtained from applied boron at the rate of 1.50 kg ha^-1. The height brinjal yield (48.26 and 76.52 t ha^-1) was also recorded with said boron level (1.50 kg ha^-1) in two consecutive years of study. It might be the reason of well management practices and soil deficient in boron. Smit and Combrink (2004), Paithankar et al. (2004) and Ben-Gal and Shani (2004) found similar findings in their investigation and confirmed the present finding.

Effect of molybdenum: The yield of brinjal was significantly augmented due to Mo application. The significant increase of growth and other yield attributes were observed with the successive addition of Mo up to 1.50 kg ha^-1 and beyond that the yield declined steadily (Table 3). However, applied 4 levels of Mo (0, 0.75, 1.5 and 2.25 kg ha^-1) the highest plant height (95.12 and 93.24 cm), fruits/plant (50.63 and 12.69 cm) and fruit weight (63.75 and 91.53 g) significantly progressed in upward trend but beyond that level the trend sharply fallen off. All the yield and yield contributing characters responded positively by adding molybdenum levels due to native soils are in Mo deficient. In the similar way yield of brinal was highly influenced by applying Molybdenum to some extent. However the highest brinjal yield (48.1 and 82.24 t ha^-1) was recorded with applied Mo at the rate of 1.50 kg ha^-1 as compared to other Mo rates and significantly differed over Mo control (Mo) and 88% yield increase recorded in same Molybdenum level (1.50 kg ha^-1).

Correlation-regression analysis: It reveals in the regression equations (Fig. 1 and 2) reflected that at the increase B and Mo levels the yield increased positively to some extent and further increment of the doses the yield declined sharply.

Fig. 1a:	Response of boron on the yield of Brinjal, 06

Fig. 1b:	Response of boron on the yield of Brinjal, 05

Table 2:	Main effects of boron on the yield and yield attributes of brinjal during 2005-2006
Figures having common letter(s) in a column are not significantly different by DMRT at 5% level., CV = Coefficient of Variation

Table 3:	Main effects of Molybdenum on the yield and yield attributes of brinjal during 2005-06
Figures having common letter(s) in a column are not significantly different by DMRT at 5% level, CV = Coefficient of Variation

Fig. 2a:	Response of molybdenum on the yield of Brinjal, 06

The values of R² (0.9244, 0.994 and 0.9924, 0.8884) indicates the variables yield and levels of B and Mo are positively correlated.

Interaction effect of B and Mo: It is evident from studied tables reveal that both B and Mo had an significant effect on the yield and yield attributes of brinjal. But incase of single effect, Molybdenum was found to be more responsive to brinjal than that of Boron (Table 4a and b).

Fig. 2b:	Response of molybdenum on the yield of Brinjal, 05

However, with the integration of B-Mo at increase rates significantly increased the studied parameters at certain levels but beyond the farther increment the upward trend sharply declined. It was happened in the study in both the years of 2004-2005 and 2005-2006. The yield and yield attributes of brinjal like plant height, number of leaves, fruit size, fruit weight and number of fruits per plant progressively increased by the increase of boron-molybdenum integration up to certain limit and thereafter this declined sharply. The highest plant height (98.40 and 93.20 cm), fruit length and diameter (16.66x6.20 and 17.06x6.59 cm), number of fruits (54.64 and 77./75/plant), single fruit weight (91.0 g) were obtained from B-Mo combination at the rate of B 1.50, M1.50 kg ha^-1 and significantly differed over other treatment combinations and B-Mo control treatment (Bo Mo).

Table 4a:	Interaction effects of boron and molybdenum on the yield and yield attributes of brinjal during 2005-2006
Figures having common letter(s) in a column are not significantly different by DMRT at 5% level., CV = Coefficient of Variation

Table 4b:	Interaction effects of B and Mo on the yield and yield components of brinjal during 2004-2005
Figures having common letter(s) in a column are not significantly different by DMRT at 5% level, CV = Coefficient of Variation

This was partially agreement with the findings of Agwah and Mahmoud (1994), Gunes et al. (1999) and Yadav et al. (2001a, b).

CONCLUSIONS

It is summarized from the two years study felt that Boron at the rate of 1.96 kg ha^-1 (optimum dose), 1.44 kg ha^-1 (econimic dose) and that of Molybdenum at the rate of 1.71 kg ha^-1 (optimum) 1.48 kg ha^-1 (economic) along with combined blanket dose of N₁₅₀ P₄₅ K₁₀₀ S₂₀ kg and CD 5 t ha^-1 were found to be optimum for maximizing yield of brinjal. So, it may be suggested that B at the rate of 1.5 kg ha^-1 and Mo at the rate of 1.50 kg ha^-1 along with a blanket dose of N₁₅₀ P₄₅ K₁₀₀ S₂₀ kg and CD 5 t ha^-1 can be suitable fertilizer package for brinjal production in Gray Terrace Soil of Joydebpur.