Agriculture Reference
In-Depth Information
2011), extend their water supply areas over a very long distance, annex-
ing the water resources of other watersheds. In a few instances, such as
in Munich (http://www.partagedeseaux.info/article226.html), a deliberate
policy was implemented to reconcile water and food production in the sur-
rounding hinterland, with organic agriculture being promoted through the
establishment of a strong public urban market demand.
The case of the huge Paris agglomeration offers an interesting example
to study the potentiality of changes in the relationships between a large
city and its food-supplying area, in particular in terms of its contribution
to the nitrogen cascade. Previous studies (Billen et al., 2009, 2011) have
traced back the geographical areas supplying food (measured as protein N
content) to the Paris agglomeration during the last two centuries, a period
when the city grew from 700 000 inhabitants in 1786 to 11 500 000 at the
present time: its per capita N consumption rose from 5.4 to 7.7 kgNcap
−1
yr
−1
, and the share of animal products in the diet increased from 39 to 65%
of total protein consumption. Part of the consumption increase is due to
higher intake, while another part is the result of higher waste generation
all along the food chain (currently estimated to about 30% of the total in
Europe, Gustavsson et al., 2011). Surprisingly, these major changes in the
city's food demand were not accompanied by a considerable extension
of the mean food supply distance, but rather by deep reorganisation, spe-
cialisation and opening of agriculture in the hinterland. On the other hand,
the Seine watershed still represents the only source of drinking water
for Paris, with two-thirds coming from surface water and one-third from
groundwater resources, both threatened by increasing nitrate contamina-
tion (Billen et al., 2007; Ledoux et al., 2007). Previous studies have also
shown that only radical changes in agricultural practices would be able to
durably reduce nitrate pollution of ground and surface water in the Seine
watershed (Thieu et al., 2010a, b; Lancelot et al., 2011).
This paper pursues the analysis of the environmental imprint of Paris's
food consumption on the biogeochemical functioning of its rural hinter-
land and attempts to bring out the relations between urban demand for
foodstuffs, nitrogen cycling in agricultural systems, and nitrate contami-
nation of water resources. We then explore the potentialities of radically
changing both the agricultural practices and the urban diet patterns for
reducing the environmental imprint of urban food consumption.
