ABSTRACT
Energy input levels are arguably the major feature distinguishing between agriculture in the developed and non-developed world, and the single most important factor underpinning greater food production by a smaller number of people. In low resource systems this energy might represent food for human beings or animals, but development usually entails increasing energy levels supplied as fuel or embodied in equipment, fertilizer or agricultural chemicals. In most cases this is derived from low cost fossil fuels, so energy economy has been low on the priority list for farmers and agricultural research organizations in the developed nations.
