Two experiments were conducted during 2010 and 2011 main cropping seasons under different farmer fields at Pawe District of Northwestern Ethiopia in order to evaluate different commercially produced microbial inoculants, referred to as commercial rhizobial strains, on soybean yield. The first experiment was conducted with the aim of evaluating four commercial rhizobial strains (Legume fix, TSBF–531, TSBF–442 and MAR–1495) on soybean yield, while the second experiment conducted with the aim of evaluating and selecting the best rhizobial strain from the two rhizobial strains (Legume fix and MAR–1495). Non-inoculated soybean with and without the recommended rate (RR) of nitrogen (N) fertilizer treatments also included in the experiments. Treatments were arranged in a single replicate per field. Recommended rate of phosphorous (P) fertilizer was applied uniformly to all treatments. The two experiments analysis of variance indicated that there was significant difference (P < 0.05) among treatments in number of nodules, nodule weight, biomass yield and grain yield of soybean. Accordingly, the first experiment result indicated that the highest number of nodules, nodule weight, biomass yield and grain yield were recorded by using rhizobial strains of legume fix and MAR-1495. The second experiment result revealed that rhizobial strain MAR-1495 resulted consistent and highest number of nodules, nodule weight, biomass yield and grain yield of soybean. The increment in grain yield over the un-inoculated control, legume fix and full RR of N fertilized treatments recorded by MAR-1495 was 25.5, 9.7 and 9.9%, respectively. Moreover, inoculation of soybean seeds with rhizobial strain MAR-1495 also resulted to higher protein content in soybean plant tissue. Therefore, this study recommends use of the most suitable commercial rhizobial strain MAR-1495 for the study area to inoculate seeds before sowing for the production of soybean crop.
Support the magazine and subscribe to the content
This is premium stuff. Subscribe to read the entire article.