Efficacy testing of in vitro diazotrophic activity of Acinetobacter on the field growth of soybean

Nitrogenase enzyme activity as a measure of nitrogen fixation by Acinetobacter genospecies3 A15 was found to be 49.56 µmoles ethylene/96h at 28 0 C. Efficacy testing of diazotrophic A15 inoculum for growth promotion at field I showed early germination, podding and flowering, increased post harvest parameters, freedom from weeds and diseases but complete absence of nitrogen fixing root nodules. The control plants were infected with mildew, stem rot and blights causing 36% mortality. The average yield of inoculated soybean was 12% over control. At field II, inoculated plants were poorly nodulated without indication of promotion of growth parameters or yield unlike control.