Abstract:
Nitrogen is a crucial element in the production of both leguminous and non-leguminous crops and has pivotal impact on
the growth of legumes. The yield of soybean mainly d1
depends on the accumulation of nitrogen and chlorophyll content
in leaves. A pot experiment was conducted to determine the effects of phosphorus (P) and plant growth-promoting
rhizobacteria (PGPR) treatments, applied in combination with Pseudomonas fluorescence and Azotobacter
chroococcum on the chlorophyll and nitrogen content in soybean (Glycine max. (L) Merr). P and PGPR were applied in
the soil before sowing. Soybean plants (cv Zodiac) were grown on soil-sand mixture with P deficiency at two water
regimes - 70% water holding capacity of soil (WHC) as sufficient supply and 35% WHC as low water supply. The
results revealed an overall increase in chlorophyll a and total chlorophyll content in the PGPR treated plants, compared
to control (unfertilized) samples under normal soil moisture conditions. With regard to P supply, chlorophyll content
was uniform in all treatments and there were no significant changes of chlorophyll concentration in normal soil water
regime. However, phosphorus supply decreased chlorophyll concentration under water stress conditions. Phosphorus
fertilization and PGPR application increased significantly the nitrogen concentration in leaves of cv. Zodiac under
sufficient water supply. Under low water supply the P application increased the concentration of nitrogen in roots in
comparison to control plants. Hence, the results suggest that the utilization of rhizobacteria and P supplemental nutrition
have the potential to enhance the chlorophyll and nitrogen content of soybean in normal water regime of soil.
