A study to determine persistence of Rhizobium inoculants on fieldgrown soybean cultivars in Ultisol in Abakaliki Southeast of Nigeria was established in a splitplot design with inoculants as the main plot and the soybean cultivars as the subplot from 20062008. The inoculants included two locally isolated Rhizobium japonicum strains EBS 1414 and EBS 2134 and an exotic strain TAL 377. The soybean cultivars were TGM 579 and TGM 2844 nonpromiscuous cultivars and a promiscuous Samsoy cultivar. Results showed that soil bulk density increased in the first cropping year 1.68 gm cm–3, relative to the preplanting result, but decreased in the postfallow ranging between 1.371.46 gm cm–3. Soil pH of the inoculated treatments in the postfallow changed from strongly acid to moderately acid. Inoculated treatments showed significant increase in nodule numbers and nodule dry weight relative to the uninoculated+N. EBS 2134 inoculant yielded the highest Ncontent of shoot, and seed yield (3.03 t ha–1) with Samsoy cultivar in the postfallow cropping period showed that there was better interaction between the inoculants and cultivars. The results obtained in this study showed that the inoculants persisted in the soil after the fallow period.
