Effect of Rhizobium inoculation and different fertility levels on symbiotic efficiency and soil properties on black gram (Vigna mungo L.) in Typic Haplustepts

A field experiment was conducted to evaluate the effects of rhizobium inoculation and different fertility levels on symbiotic efficiency and soil properties of blackgram at Instructional Farm, Rajasthan College of Agriculture, Udaipur during kharif, 2017. nbsp;The experiment comprised four rhizobium strains (Indigenous strains I, Indigenous strains II, Commercial I and Commercial II), one uninoculated control and four fertility levels (0, 50, 75, 100% RDF). The complete randomized blocks design in factorial arrangement was used with three replications with variety PU-31. The soil of the experimental site was clay loam in texture slightly alkaline in reaction, medium in available nitrogen and phosphorus and high in potassium and sufficient in micro nutrients. Results indicate that seed inoculation with Indigenous strains I significantly increased number of total nodules plant-1, effective nodules plant-1, fresh weight of nodules plant-1, dry weight of nodules plant-1, leghaemoglobin content at nodulation stage, The organic carbon, available nitrogen, phos phorus, potassium, copper, zinc, iron and manganese in soil increased significantly, whereas, the effect on pH and EC were found to be non-significant, bacterial population, fungal population, actinomycetes popu lation, alkaline phosphatase activity and dehydrogenase enzyme activity soil increased significantlyat har vest over both commercial strains as well as uninoculated control. However, it was found statistically at par with Indigenous strain II. Similarly, application of 100% RDF significantly increased number of total nod ules plant-1, effective nodules plant-1, fresh weight of nodules plant-1, dry weight of nodules plant-1, leghaemoglobin content at nodulation stage andThe organic carbon, available nitrogen, phosphorus, potas sium, copper, zinc, iron and manganese in soil increased significantly, whereas, the effect on pH and EC were found to be non-significant with the application of different fertility levels after harvest of the crop. In biological properties bacterial population, fungal population, actinomycetes population, alkaline phosphatase activity, dehydrogenase enzyme activitysoil increased significantlyat harvest over all fertility levels.