Several studies have shown that changing from conventional to organic farming is an alternative to reduce negative impacts on the environment, for example nitrogen losses, reduced biodiversity and input of fossil energy per unit land and per unit product. In organic agriculture, as well, there is currently a trend towards specialized farming systems. To compensate for the lack of data on energy efficiency measured at farm scale, a comparison between three differently managed organic all-arable crop rotations and a typical rotation of typical regional N-intensive conventional farm was carried out over a two-year period at a highly productive site in northern Germany. Comparing the all-arable crop rotations, the organic systems had a 62 % lower output measured in MJ metabolizable energy. Due to a 74 % lower input of fossil energy, the organic crop rotations showed a 37.7 % higher energy efficiency than the compared conventional rotation. Taking into account the area of land needed to produce the same amount of energy, the conventional system was more efficient. The net energy gain per hectare (derived from subtracting energy input from the gross energy output) of the conventional farm of 95.96 GJ ha-1 was considerably higher than the average of the 3 organic crop rotations (39.69 GJ ha-1)
