'A field experiment was conducted at Nubaria Agricultural Research Station
Farm on a calcareous soil of 26% CaC03 to study the positive effect of inoculation
with phosphate dissolving bacteria (POB) and phosphorus application on wheat.
There were two factors under study (1) phosphorous fertilization (5 rates, 0-26 kg
P/fed.) and (2) bacterial inoculation using phosphate dissolving bacteria (POB), under
a trade name of Phosphorine, (two treatments: with, B" and without, Bo-). Wheat
(Triticum aestivum L., var. Sakha 8) was sown in the two winter seasons 1998/99 and
1999/2000. Grain yield of wheat (Sakha 8) increased by 30.4 % (almost one third,
0.67 Mg/fed equals 670 kg/fed) with using A2B, treatment (13 kg P/fed + inoculation).
Inoculation with POB increased grain yield of wheat by 10 % when combined with 13
kg P/fed (A2B, treatment) . This treatment might be recommended as a good P
fertilization treatment for the tested wheat variety grown under the same condition of
soil. Dry weight of individual plant was increased by 8.3 and 11.7 % in the case of
absence P addition and in the presence of inoculation (AcB, treatment) in the first and
second seasons, respectively. Weight of plant increased more with P up to AJ rate (13
kgP/fed) with inoculation. Inoculation with POB had a little effect on P concentration in
plant after 30 days of sowing, but a significant positive effect was noticed after 60
days of sowing. The action of inoculation and activity of phosphorus dissolving
bacteria needed time to affect soil reaction, as the beneficial effect of inoculation with
PDe on decreasing soil pH increased with time. Available P decreased with time
indicating P fixation by soil components and/or utilization of available P by the growing
wheat plants. The highest activities of POB were observed after 60 days of sowing,
since the populations of POB were higher than those after 30 days of sowing and after
harvest.