Concepts naming a historical turning point or a technology that changed how farming works at scale, and the systems that carry science to the working farmer, including the Columbian Exchange, the Green Revolution, the Haber-Bosch process, agricultural extension and sustainable agriculture. Belongs here: any concept defined by a named historical transformation, a foundational technology, or the ongoing transfer and renewal of agricultural knowledge and practice. Does not belong here: a concept about genetic material or a natural land process on its own, grouped under Genetic Resources and Crop Diversity or Soil and Environmental Processes respectively.