Phosphorus inputs relate to synthetic fertilizer for arable lands,
animal feed and human food imports, as well as green waste (Fig. 4).
Phosphorus outputs include agricultural production (arable land,
grasslands, and forestry), local population wastes managed at a region
scale, urine and feces, organic products for fertilization (manure and
compost), and finally leaching and erosion. The four highest phosphorus flows in the agri-food system (75% of total flows) are human
food imports, urine and feces exports, synthetic fertilizers for arable
land imports and arable land production exports. Regarding phosphorus flows, these figures confirm the clear uncoupling between
agriculture and local food consumption on the Saclay plateau.