Current energy supplies are finite and are being used at an ever increasing rate. We can no longer evaluate alternatives on a cost basis alone. Crop production systems are no exception. We must now evaluate such systems on energy-use and environmental impact bases as well as on a cost basis.This study was to develop and compare energy budgets for wheat, grain sorghum, and wheat-grain sorghum rotation tillage systems. Energy inputs considered included machinery and parts manufacturing, crop production fuel, and tire and herbicide manufacturing.Our results show that energy requirements for crop production tillage systems vary considerably. Fuel consumed by tractors in performing the tillage operations was the largest input (39.6-82.5% of the total). Energy for herbicide, however, was almost as large as the fuel input for the grain sorghum no-till system. No-till systems use slightly more energy than till-plant tillage systems for grain sorghum (60.8 versus 54.5% of conventional). Wheat conservation tillage systems use less energy than do conventional tillage systems that include moldboard plowing (82.9% of conventional). One broadcast application of atrazine reduced the tillage energy for a wheat-grain-sorghum rotation system 16.7%.