The presence of nitrogen fixing bacteria can be insured by inoculating the seed planted in soils that have never had soybeans planted on them. Inoculation of soybean seed may be applied to the seed just before planting time. For soil that has never had soybeans, it may be best to use as much as three times the recommended rate of inoculum the first time soybeans are grown. Retreatment of inoculum is not necessary unless more than four years elapse between soybean crops as the bacteria continue to live in the soil. Viable inoculant should be kept in a cool area prior to applying to the seed the day of planting.
Soybeans require relatively large amounts of phosphorus.
The seed and vegetative parts of a crop yielding 4,707 kilos per hectare. Soybeans remove large amounts of potassium from the soils. In general, final soybean populations of 300,000 to 350,000 per hectare are desired. Row spacing should be as close as practical so that the soybeans can shade the ground soon after planting, thus providing assistance for weed control. As row spacing narrows, fewer plants per meter of row are needed to achieve a given population more common than too little.