ABSTRACT
Use of rotations is a cornerstone of any sustainable agricultural system. Rotations that contain a close-growing crop, such as a forage, also can be important in developing a soil and water conservation plan. Over a large portion of the United States, conservation tillage systems are the most promising management practices to achieve the required erosion reductions. Rotations of dicotyledenous and monocotyledenous crops allow use of low-cost herbicides to achieve good weed control. Rotations that provide the best economic returns are generally those from which the legume develops seed that can be harvested as a cash crop. After the farm has adjusted to the new rotation over time, machinery costs may not differ substantially on a per-hectare basis. Machinery cooperatives have been established or proposed in several areas of the world. Timeliness costs have been determined for various operations.
