The Usefulness of Bean Nodulation Data Relative to Other Symbiotic Parameters in Judging Success ofRhizobiumInoculation

In assessing the effect of Rhizobium inoculation on legumes, nodulation data, absolute numbers or nodule dry matter per plant are often used as initial indicators of inoculation success. A detailed study was undertaken to examine the usefulness of nodulation data in relation to other parameters including shoot dry weight, nitrogen content, nodule volume and percent nodule occupancy by inoculum strains using the ELISA technique. Two strains of rhizobia and three different methods of inoculation were used. The inoculation methods included: seed pelleting; seed pelleting followed by side-dressing and direct soil inoculation. Results of this study indicate that regardless of the inoculation method or Rhizobium strain, absolute nodulation data were not useful parameters in assessing the success of inoculating beans with Rhizobium.