This thesis reports a comprehensive analysis of a field nodulation problem. The failure of seed inoculation of soybean (Glycine max) with Rhizobium was demonstrated in the blade earths. Similar difficulties occurred with mungbean and navy bean.
Failure of nodulation was correlated with failure of inoculum to establish in the rhizosphere.
Edaphic and environmental factors were responsible for the failure of the inoculum while biotic factors were apparently not involved.
Soil alkalinity, low moisture and high soil temperatures were implicated but cumulative evidence indicates soil alkalinity to be the most important.
Seed exudates, soil nitrogen and nutrient deficiency were not significant factors in survival.
Where rhizobia were present in the rhizosphere, soil moisture, aeration and induced nutrient deficiency determined the formation, growth and activity of nodules.
Improved nodulation was achieved by Rhizobium strain selection, the use of higher levels of inoculum and seed pelleting with non-alkaline material whereas soil nutrient amelioration provided no solution.