Organic agriculture ostensibly offers a concept of sustainable practices based on environmental responsibility. It is widely believed that organic principles based on natural means and methods are environmentally sound and thus superior to systems based on artificial inputs. This overview summarises the main results on organic agriculture and highlights relevant facts in order to provide scientific information about the potential and limitations of organic agriculture. The topics of food security and safety, environmental quality, system sustainability and energy consumption are addressed. Some of the main conclusions are that organic agriculture has consistently lower yields than conventional production and is thereby a less efficient method of land use; that environmental problems caused by processes such as nutrient leaching are not reduced by conversion to organic crop production; and that soil fertility status and microbial biodiversity are not improved a priori by organic cropping. The energy investment for production of artificial N fertilisers results in a five- to ten-fold energy return in the form of biomass and this highly positive energy balance needs to be fully acknowledged. The future challenge of developing sustainable forms of agriculture to provide sufficient food for a growing world population with minimal environmental disturbance deserves our wholehearted and unbiased attention
