Effects of inoculations of Glomus mosseae and/or Bradyrhizobium japonicum on formation and distribution of nodules and phosphorus uptake of soybean

A pot experiment was carried out to investigate the effects of inoculation of Glomus mosseae (GM) and/or Bradyrhizobium japonicum (BJ) on the formation and distribution of nodules and phosphorus uptake of soybean at the 28th and the 56th d after inoculation. The results showed that at the 56th d after inoculation, compared with the treatment BJ inoculation, the plant biomass, P and N concentrations, the number of lateral roots with nodules, nodules on lateral roots, were increased in the treatment of GM and BJ inoculation. With BJ inoculation, the total nodule number in the taproots and lateral roots were 48.4% and 51.6%, respectively; while with both GM and BJ inoculation, the number in the taproots and lateral roots were 32.5% and 67.5%, respectively. The nitrogenase of the treatment with both GM and BJ inoculation was higher than each of the single inoculation treatment. The AMF inoculation rate of the treatment with both GM and BJ inoculation was increased, especially that in the lateral roots with nodules was higher than that without nodules. On the 28th d after inoculation, the phosphorus absorption efficiency of AM inoculation treatment was higher than that with double inoculation treatment; while on the 56th d after inoculation, the phosphorus absorption efficiency in the treatment of double inoculation was higher than each of the single inoculation treatment. In conclusion, AMF inoculation changed the distribution of nodule in the roots, which was positively related with the AMF inoculation.