The early soybean production system (ESPS) is the highest yielding soybean production system in the mid-southern U.S. but requires subsoiling to maximize yield and profitability. The inclusion of cereal rye as a cover crop in conservation tillage systems may be a means to increase ground coverage and reduce tillage in the ESPS. The objective of this research was to determine the effects of monoculture cover crops on soybean yield, net returns above specified costs, and water use efficiency in conservation tillage systems.