The results of the soybean inoculation studies reported in this bulletin were obtained under field conditions, and the experiments extended over a period of three years. These studies included the testing of different ways of applying inoculated soil to soybean seeds as well as to the soil, and also the testing of a number of commercial cultures, secured from different sources, on the inoculation of soybeans. Data have also been reported which show the relative efficiencies of soil from different sources, pure cultures of soybean bacteria, and different commercial cultures on the inoculation of different varieties of soybeans. The effects of inoculation, lime and lime and superphosphate, on the percentage of nitrogen in soybean plants have also been noted.

In some cases the experiments were repeated for two or three years, and the results obtained each year agreed remarkably well.