Saviour et al.

at mineral surfaces as well as B that has isomorphously

ha -1 . The highest amounts of soil boron originated from

replaced Al or Fe within the octahedral sheet of the

residual form, generally ranged from 70 to 99% of total

minerals. The results also corroborate with earlier findings

soil B (Raza et al., 2002). This form of boron accounted

of Hoe et al., (1994).

major contribution to total boron among all other boron

fractions (Karthikeyan and Shukla, 2011).

Organically bound boron (Tables 2 and 3)

Conclusion

The boron level at @ 2.0 kg ha -1 had increased the

organically bound boron content at 0, 7, 15, 21 and 30

From the incubation experiment, it was inferred that with

days after incubation (0.46, 0.49, 0.75, 0.87, 0.85 and

applied boron, the non - specifically adsorbed B fraction

0.43, 0.46, 0.72, 0.84, 0.82 mg kg -1 respectively in both

was higher next to residual form when compared to other

the locations. The organically bound boron fraction in

forms of boron. Applied B converted to this soluble form

soils increased with levels of boron application. From

and attained peak values (1.03 and 1.0 mg kg -1 mg kg -1 ) at

the beginning to end of the incubation period, both soils

21 days after incubation in the treatment with application

recorded the highest organically bound boron fraction

of 2 kg B ha -1 and thereafter a decrease was noted.

content with 0.87 and 0.84 mg kg -1 on 21st day of

The plant available form of B includes non-specifically

incubation due to application of B @ 2.0 kg ha -1 . The

adsorbed B fraction which was considerably higher on

level of boron at @ 2.0 kg ha -1 increased the organically

21st day after incubation which coincides with the high

boron which ranged from 0.03-0.81 and 0.02-0.84 mg

demand for B by maize crop during vegetative phase.

kg -1 with higher content of 0.87 and 0.84 mg kg -1 on 21st

day and contributed to 0.02 and 0.01 per cent of total

Acknowledgments

boron respectively in both the locations due to application

The author acknowledges the chairman and the advisory

of B @ 2.0 kg ha -1 . This form of boron increased with

committee members who provide their valuable guidance

increasing levels of boron which solely depend on the

to conduct this incubation experiment.

organic carbon content of the soil (Karthikeyan and

Shukla, 2011).

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