Crop rotations for the 21st century

Advantages and disadvantages of crop rotation have undoubtedly been debated for thousands of years, as documented by historians (White, 1970b) who have stated that rotation systems were widely recommended by Roman agronomists, but often not adopted by local farmers. One reason for farmer hesitancy to use crop rotation may be that agricultural scientists are still unable to explain the mysterious “rotation effect.” Macroeconomic and microeconomic considerations have and presumably will always influence land use decisions, such as adoption of crop rotation. For the U.S. corn belt, this was well documented by Wiancko (1927), but economic considerations must include a more complete accounting for both on-site and offsite impacts of our soil and crop management practices. Benefits of crop rotation for land and water resource protection and productivity have been identified, but processes and mechanisms responsible for those benefits need to be better understood. This is a critical area for basic and applied research. Public policies that influence land use decisions, such as crop rotation, need to be as flexible as possible to encourage adoption of practices that are economically viable, environmentally sustainable, and socially acceptable. Following this agenda will ensure that crop rotations have a major role in 21st century agriculture.