The fertilization rate and placement methods of phosphorus and potassium fertilizers can positively affect soybean [Glycine max L. (Merr.)] seed composition and yield in some environments, but not in others. Soybean seed production costs and chemically-treated seed disposal costs have increased, coinciding with farmers' adoption of planting chemically-treated soybean seeds. Seeds are treated with fungicides and sometimes with insecticides to provide protection from pathogens and insects before seed emergence. These changes in production costs have renewed seed industry's interest in identifying agronomic practices that enhance soybean quality, composition, and storability. Soybean seeds do not store well and seed quality declines faster than seeds from other agronomic crops because of their high oil content. Seed quality is defined for this study as seed viability, seed vigor, seed composition, and the fatty acid profile of the oil in seeds and their relationship to seed storability. Before the adoption of chemically-treated soybean seeds, unused, untreated seed was returned to seed dealers and sold in the commodity market. But today, many seed lots are chemically-treated and returned seed must be disposed in an environmentally safe manner. Many producers' storage sheds are non-climate controlled so wide variations in temperature and relative humidity reduce seed quality due to the inadequate environment for seed storage. Chapter 2 investigates the effects that phosphorus and potassium fertilization have on initial seed quality and vigor, as well as changes that occur in the composition of oils and proteins within the seed. Chapter 3 documents changes in soybean seed storability in response to phosphorus and potassium fertilization in multiple storage environments.