The role of Molybdenum in relation to Rhizobium sp. in increasing biological Nitrogen fixation and soybean growth

Soybean is a legume that can form a mutualism symbiosis with Rhizobium bacteria to bind N. Increasing the effectiveness of N fixation by Rhizobia requires the role of micronutrient Molybdenum (Mo), because Mo is needed for nitrate reductase enzyme for NO₃^- assimilation. The objective of the research was to evaluate the role of Mo and Rhizobium sp. inoculation in the growth of soybean and increase the root nodules number. A factorial randomized block design was used in the research. The first factor was inoculation of Rhizobium sp. (0; 5 and 10 ml/plant), and the second factor was the application of Mo (0; 200; 400 and 600 g/ha). The research result showed that inoculation of Rhizobium sp. up to 10 ml/plant increased plant height, number of leaves and leaf area. Application of molybdenum up to 400 g/ha was able to increase the number of nodules formed. There was no significant interaction between Rhizobium sp. inoculation and application of Mo in all observed variables.