الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Two pot experiments have been done in two successive agricultural seasons (1998-1999, 1999-2000) to study the effect of inoculation with rhizobia and phosphate dissolving bacteria in the presence of four levels of mineral nitrogenous fertilization (Zero, 30, 60, and 90 units nitrogen / fedden) on the growth and yield of broad bean. The experiments have been done in pots under the conditions of green house in Desert Research Center by using sandy soil obtained from the 10111 Ramadan of and all the pots have received organic matter
(1%) ammonium nitrate 33% was used as a mineral nitrogen fertilizer.
Supper phosphate (P2O5 15.5%) 200Kg/Fedden and potassium sulfate 48% (100 k g/fedden) were used in the first experiment, i.e. uninoculated and rhizobial inoculated treatments but in the second pot experiment, there were three treatments as follows: without inoculation, rhizobial inoculated and mixed inoculated treatment (rhizobia and Bacillus tnegaterium). The used bacterial strains were prepared in microbiology lab of Desert Research Center and the pots have been arranged in complete random manner in the green house.
The soil samples were collected at 35, 70 and 105 days to determine the total microbial counts, Azotobacter densities, azospirella and phosphate dissolving bacteria and total nitrogen. Also plant samples were collected at 35, 70 and 105 days to determine the following parameters:
First experiment:
1-Total nitrogen in soil:
The increasing of mineral nitrogenous fertilization rates with inoculation by Rhizobinni resulting in; a significant gradual increase in soil nitrogen at 70, 105 days from plant age, in comparison with the same mineral nitrogenous fertilization rates in case of absence of inoculation with Rhizobium.
2-In generally the total microbial count, total count of azotobacters and total count of azospirella increased at 70 days and then significantly decreased at 105 days. Also the increasing of the rates of mineral nitrogenous fertilization at 30, 60 unit N/fed. With inoculation by rhizobia caused a significant increment in the total number of microbial count, Azotobacter and azospirella counts in comparison with uninoculated treatments at 70 days and then a general decrease was occurred
at 90 unit N/feddan.
3 — A significant increase in the total nitrogen content in shoots, roots and root nodules has been occurred at 70days from plant age while general decreasing in total nitrogen occurred at 105 days. Inoculation by rhizobia. with increasing of mineral nitrogenous fertilization rates caused a general increase in the total nitrogen content for shoots , roots and root nodules.
4-Inoculation by rhizobia with the increasing of mineral nitrogenous fertilization rates caused a significant increase in the activity of nitrogenase enzyme at 70 days, after that, sharp decrease has bean occurred at 105 days.
5-Inoculation with rhizobia caused a significant increase in the total nitrogen content of seeds in comparison with uninoculated treatments. The increment was higher than those which resulted from mineral fertilization.By proceeding of age of plant, an increment in the dry weight of shoots, roots, root nodules and number of nodules was occurred rill 70 days and then a general decrease occurred for this treatments at 105 days. Inoculation with rhizobia resulting in a great increment in the previous treatments than the uninoculated treatments especially at 30, 60 unit N/feddan, which at all times was better than 90 unit N/feddan.
7-Increasing of plant age caused an increase of plant heights in general. Increasing of mineral nitrogenous fertilization rates accompanied by inoculation with rhizobia had a significant effect on increasing plant heights in comparison with uninoculated treatments.
8 — the number of branches was increased with the gradual increasing of mineral nitrogenous fertilization in the presence of rhizobia than those of uninoculated. There was not any increment in the number of branches with proceeding of age plant from 70, 105 days.
9-Inoculation with rhizobia by adding 30 unit N/feddan caused an increment in leaf area and chlorophyll than noninoculated treatments or in case of increasing mineral nitrogenous fertilization to 90 unit N/feddan.
10- Inoculation with rhizobia in the presence of 60 and 30 unit N/feddan gave the highest yield of seeds while the yield decreased at 90 unit N/feddan in comparison with uninoculated
treatments.Second experiment:
1- Mixed inoculation (R+PDB) or by rhizobia only gave a great value of increment in the total nitrogen content of soil at 35 and 70 days in comparison with uninoculated treatments. After that a gradual decrease of the total nitrogen content occurred for all treatments.
2 - The total microbial count and both Azotobacter and azospirella counts increased to the highest rate by using mix inoculation of rhizobia and PDB at 70 days in the presence of 60 and 30 unit N/feddan then a decrease occurred at 105 days with 90 N /feddan inoculated treatments, and was lesser in this counts but it outmatched uninoculated treatments.
3-Mixed inoculation (R +PDB) gave increasing in PDB counts and the increment which recorded at 60 unit N/feddan was higher than 30 and 90 unit N/feddan at 70 days. The number of this counts decreased at 105 days, also inoculation with rhizobia caused an increment in PDB counts than uninoculated treatments.
4-Mixed inoculation (R +PDB) n he resence f 0 nit N/feddan at 70 days caused the highest rate of total nitrogen for shoots, roots and root nodules. A decrease occurred in the total nitrogen content at 105 days, also inoculation with rhizobia only caused a significant increment in nitrogen content than the uninoculated treatments at different nitrogen levels.
5-Mixed inoculation (R +PDB) gave the highest rate of total nitrogen in seeds followed by inoculation with rhizobia only than uninoculated treatments.
6-The highest rate of activity of nitrogenase enzyme was Orecorded at 7 days in the presence of 30 and 60 unit N/feddan incase of mixed inoculation (R + PDB) followed by inoculation by rhizobia only in comparison with uninoculated treatments.
7-the highest dry weight of both shoots and roots was recorded at 105 days in the presence of 60 unit N/feddan in case of mixed inoculation (R + PDB) or in case of inoculation with rhizobia only in comparison with uninoculated treatments. An increment in dry weights of shoots and roots caused by increasing mineral
nitrogenous age plant till 105 days.
8-The highest rate of number of nodules counts and their dry weight were recorded at 70 days in the presence of 60 unit N/feddan in case of mixed inoculation (R+ PDB) followed by case of rhizobia only and finally with uninoculated treatments.
9-Plant heights and number of branches increased to the highest rate at 70 days, then a stability state occurred to it. The highest result was obtained in the presence of 60 unit N/feddan in case of mixed inoculation (R +PDB) followed by the case of inoculation with rhizobia only and finally uninoculated treatments results at the same nitrogen levels and the same age.
10-Mixed inoculation (R+PDB) outmatched the using of Rhizobium inoculation only in the presence of 60 unit N/ feddan at 70 days on the effect of both leaf area and chlorophyll percentage, while a decreasing occurred for this treatments at
105 days.
11-The highest yield of seeds was obtained by using mixed inoculation (R+PDB) in the presence of 60 and 30 unit N/feddan followed by the results of using inoculation with Rhizobium only with a great value higher than uninoculated treatments.