Localising the nitrogen imprint of the Paris food supply: the potential of organic farming and changes in human diet

[摘要] The Seine watershed has long been the food-supplying hinterland of Paris,providing most of the animal and vegetal protein consumed in the city.Nowadays, the shift from manure-based to synthetic nitrogen fertilisation,has made possible a strong land specialisation of agriculture in the Seinewatershed: it still provides most of the cereal consumed by the Parisagglomeration, but exports 80% of its huge cereal production. On theother hand the meat and milk supply originates mainly from regions in theNorth and West of France, specialised in animal farming and importing about30% of their feed from South America. As it works today, this system isresponsible for a severe nitrate contamination of surface and groundwaterresources. Herein two scenarios of re-localising Paris's food supply areexplored, based on organic farming and local provision of animal feed. Weshow that for the Seine watershed it is technically possible to design anagricultural system able to provide all the plant- and animal-based foodrequired by the population, to deliver sub-root water meeting the drinkingwater standards and still to export a significant proportion of itsproduction to areas less suitable for cereal cultivation. Decreasing theshare of animal products in the human diet has a strong impact on thenitrogen imprint of urban food supply.

[学科分类] 地球化学与岩石