Two pot experiments were carried out during the seasons of 1999 and 2000
at Agricultural Research Center in ·Giza using a calcareous soil media to investigate
the effect of phosphate dissolving bacteria (POE?) inoculation, sawdust compost and
different nitrogen sources on growth and yield.of okra plants. Moreover, the changes
in some . biological and chemical properties of the used soil after 175 days of planting
were also recorded. 8acillus-megatherium var p < /em>hosp < /em>haticum was used as inoculum at
the time of planting. While, two rates from sawdust compost were used, i.e. 2.5% and
5% in addition _ to the control treatment. The nitrogen fertilizer was added at four
sources nam-ely, (8) nitric acid solution (0.1,ti), (C) nitric acid- calcium nitrate (1: 1)
mixture, (D) calcium nitrate solution and' (E) urea solution on nitrogen basis compared
with no mineral nitrogen application (A). The obtained results indicate that, inoculation
of okra plants with POB and addition of sawdust compost significantly increased plant
.growth, fruits yield and nutrients uptake. The highest increments of this parameter
were. achieved. under usedhiqher compost rate (5%) than 2.5%. The obtained results
show also that, nitrogen· fertilization: was very· important to okra plants in such soil
. regardless the' form of added nitrogen. On the other hand, the completely and partially
acidic' nitrogen form induced a positive effect on the availability of nutrients such as P
and K which is reflected on uptake by plant fruits. Viable microbial counts, phosphate
dissolving bacteria and dehydrogenase activity in the soil as well as the availability of
mineral N, P and K were enhanced by organic manuring and inoculation with POB.
Moreover, the addition of organic manure increased the organic matter percentage in
the soil and lead to a slight decrease in its pH value. Therefore, adding sawdust
compost to a calcareous soil in presence of acidic nitrogen fertilizer form as well as
POB inoculation could be recommended to obtain the best results for okra fruits yield
and favourable nutrients uptake.