Bretagne, in the West of France, concentrates 40% of the country’s
intensive livestock farming, producing 56% of the country’s
pigs, 31% of its poultry and 21% of its dairy products (Savelli and
Cebron, 2006). Intensive livestock production has also positioned
Bretagne as one of the most polluted regions in France, especially
with respect to nitrate in ground and surface water, as organic and
mineral Nitrogen (N) applied largely surpass crop needs. It has been
calculated that as much as 103,000 tons of N (30% of the total N
applied) are applied in excess of crop needs, 65% of which come
from animal manure (Cebron and Ferron, 2003).