Keywords: organic farming, crop nutrition, crop yields, food production, sustainable agriculture, Badgley et al (2007).
A recent paper Badgley et al. (2007) claimed that organic farming, if used worldwide, would provide sufficient food for a growing world population. The paper stimulated much critical response. Our paper makes a critical assessment of this claim for wheat, a major cereal crop and source of food throughout the world. We consider the problems of using experimental yields in estimating the productivity of any crop or faming system and then look at farm yields, comparing organic and conventional systems. We examine in detail the comparisons made by Badgley et al. and find many of them unsupportable: the ratio of organic : conventional wheat yields of 0.85 proposed by Badgley et al. we believe to be closer to 0.65. Nitrogen (N) fixation by legumes, the main source of N supply in organic systems, is shown to be much too small and variable to support large and consistent wheat yields of acceptable quality, and ideas that cereals could one day fix their own N found wanting. Our conclusion therefore contradicts that of Badgley et al. but agrees with that of a recent report by the University of Reading’s Centre for Agricultural Strategy that organic agriculture cannot feed the world using current technologies and with the meat-rich diet that people have or aspire to. We do, though, agree with Badgley et al.’s view that there is a need to improve soil quality by adding organic material, reducing over-optimal use of fertilisers and agricultural chemicals, and optimising rotations to reduce losses to pests and diseases. There is also, perhaps, a wider societal need for people to reconsider diet in the context of their health and the ability of the world to supply the wants of its anticipated 9 billion population.
Keith W T Goulding, Department of Soil Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
Anthony J Trewavas, Institute of Molecular Plant Science, University of Edinburgh, Edinburgh EH9 3 JH, Scotland.
Ken E Giller, Professor of Plant Production Systems, Wageningen University, Haarweg 333, 6709 RZ Wageningen, The Netherlands.
28 pages, 2 figures, 3 tables, 87 references.