A study in eastern Nebraska looked at how different previous crops and fallow land affect the yields of corn, soybeans, and grain sorghum. Corn yields were the most variable and sensitive to previous crop effects. Yields were highest after fallow, with corn, soybeans, and sorghum producing 74%, 25%, and 10% more following fallow compared to monoculture yields. In years with average rainfall, a corn-soybean sequence gave the best yield, while in years with above- or below-normal rainfall, a sorghum-soybean sequence was most productive.