Use of gram-positive phosphate solubilizing bacterium Bacillus aryabhattai in warm-water fishpond to reduce the application of phosphorus chemical fertilizer

Abstract

Introduction: The aim of this study was to investigate the possibility of replacing Triple
superphosphate chemical fertilizer with biofertilizers as an environmentally friendly approach.
Materials & Methods: The effect of separate and combined triple superphosphate and
biofertilizer application under microcosm (Erlenmeyer contains sediment) was evaluated.
Gram-positive Phosphate solubilizing bacteria Bacillus aryabhattai strain SB.P3 was used in
two levels of inoculation and non-inoculation, and phosphate fertilizer in 4 levels of 0, 30, 70
and 100%. In this experiment, soluble phosphorus, pH and density of solvent bacteria were
measured at different times (on days zero (before inoculation), 2, 5, 10, 15 and 20 days after
inoculation).
Result: The results showed that the bacterial density during the experiment in all groups, in
first had an increasing trend, then decreased, and again slightly increased. Treatment 6 (70%
fertilizer + bacteria) had the highest bacterial density, which in some time periods was
significantly different from other treatments. The amount of water soluble phosphate in all
groups at first had an increasing trend, then decreased and then increased again. At different
time intervals, no significant difference was observed in the mean of dissolved phosphorus in
the treatments with the control. Changes in pH of the treatments indicate a sinusoidal trend in
different intervals.
Conclusion: Although the bacteria grew well under microcosm and showed good stability in
the environment, the results showed that chemical fertilizers and phosphate solubilizing
bacteria didn't have a significant effect on fluctuations in soluble phosphorus.