Hydrogen metabolism and nitrogen fixation of soybean (Glycine max. L.) inoculated with different strains ofRhizobium spp.

Hydrogenase activities and N2-fixing capacities of soybean nodules (Glycine max. cv. Hodgson), inoculated with strains ofBradyrhizobium japonicum andRhizobium fredii from different geographical regions, were measured after 35 days of culture under controlled conditions. Of the strains tested, 47% induced nodules with bacteroids which recycled H2. The data obtained suggest that H2-recycling ability is not a major factor influencing early N2-fixation which depends essentially on the precocity and intensity of the initial nodulation.