RESPONSE OF FABA BEAN (VICIA FABA L.) TO COMBINED INOCULATION WITH RHIZOBIA, VA-MYCORRHIZAE AND PHOSPHATE SOLUBILIZING BACTERIA UNDER SANDY SOIL CONDITIONS

A pot experiment was conducted at controlled greenhouse of Bio-fertilizers production Unit; Soils, Water and Environment Research Institute, ARC, Giza through the winter growing season of 2006/2007 to evaluate the effects of symbiotic ni-trogen fixing bacteria (Rhizobium leguminosarum bv. viceae), phosphate solubilizing bacteria (Bacil-lus megaterium var. phosphaticum) and VAM fun-gus (Glomus sp.) on nodulation, N2-fixation, growth, N and P uptake of faba bean plants grown in phosphorus-deficient sandy soils. The obtained data resulted in significant increases in VA- Mycor-rhizal colonization ratios when soil inoculated with rhizobia and VA-Mycorrhizae as compared with the other treatments. In addition, rock-P fertilized plants exhibited significant increases in VAM colo-nization ratios when compared with those supple-mented with super-P. Concerning of dual inocula-tion with Rhizobium and Bacillus, the results indi-cated higher increases in VA- mycorrhizae coloni-zation ratios as compared with the uninoculated or inoculated treatments with rhizobia alone, being most pronounced in the rock-P amended soil. The obtained results showed clearly that combined inoculation of faba bean with rhizobia and VA-Mycorrhizae in a soil amended with rock-P or su-per-P, gave the highest significant increases in nodulation, nitrogen fixation, plant biomass, N and P uptake when compared with the plants inoculat-ed with Rhizobium alone. On the other hand, com-bined inoculation with Rhizobium and Bacillus megaterium did not record significant influence on the abovementioned parameters as compared to inoculation with Rhizobium alone.