Influence of Phosphate Dissolving and Nitrogen Fixing Bacteria on Faba Bean Under Different Levels of Phosphorus Fertilization

Abstract

A field experiment was conducted in a silty clay soil at Damas village, Mit Ghamr, Dakahlia using faba bean during 2007-2008 winter season to study the response of faba bean (Vicia faba L.) cv. Giza 3, to inoculation with Rhizobium leguminosarum bv. Viciae either solely or dually with Bacillus megatherium var. phosphaticum under three levels of phosphorus fertilizer (0, 15 and 30 kg P2O5 fed -1 ) on leaves chlorophyll content, nodulation, seed yield and its components and seed protein. Also on N, P and K content of seed and straw, available nitrogen and phosphorus in soil and numbers of phosphate dissolving bacteria in rhizosphere plant after 30, 60 and 90 days from sowing. Results revealed that the dual inoculation with Rhizobia and Bacillus gave significant increases in chlorophyll a and a + b, number of nodules/plant, dry weight of nodules/ plant and nitrogenase activity after 75 days from sowing. Yield and its components, seed protein % and seed protein content increased significantly by inoculation or increasing of phosphorus fertilizer rate or their combination where, the increase in seed yield and seed protein content recorded about 35 and 57%, respectively, over control (uninoculated treatment).Regarding N, P and K content in faba bean seed and straw, data showed significant increases as a result of increasing in P fertilizer or due to bacterial inoculation especially a dual inoculation. The soil available P and N increased significantly by either inoculation or P-fertilizer, in response to the use of 30 kg P2O5 fed -1 .Finally, results confirmed the necessity of dual inoculation with Rhizobia and Bacillus in combination with applying 30 kg P2O5 as P-fertilizer for faba bean growth and productivity and for improvement of soil fertility.