|Title||Nitrogen flows in global pork supply chains and potential improvement from feeding swill to pigs|
|Author(s)||Uwizeye, Aimable; Gerber, Pierre J.; Opio, Carolyn I.; Tempio, Giuseppe; Mottet, Anne; Makkar, Harinder P.S.; Falcucci, Alessandra; Steinfeld, Henning; Boer, Imke J.M. de|
|Source||Resources, Conservation and Recycling 146 (2019). - ISSN 0921-3449 - p. 168 - 179.|
Animal Production Systems
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Animal production - Food wastes - Life cycle - Livestock - Nitrogen use efficiency|
The global pork sector contributes to food security and supports livelihoods for millions of households but also causes nitrogen (N) pollution. Here we assess N flows, losses, and N use indicators for global pork supply chains, from “cradle-to-primary-processing-gate” and for three production systems: the backyard, intermediate and industrial systems. Subsequently, we evaluate the effects of feeding swill to industrial pigs on N flows and land use. To produce 3.5 Tg N of pork globally, 14.7 Tg N are lost into the environment, of which 68% is lost to watercourses in the form of nitrates and organic N and the reminder emitted to the atmosphere as N-gas (e.g., NH 3 , NOx and N2O). We found that the efficiency of N use, hotspot and magnitude of N losses per unit of area depend chiefly on the region (agro-ecological and economic context), origin of feed, and manure management systems. Swill feeding increases N use efficiency and reduces N losses at the feed production stage. It achieves a saving of 31 Mt of soybeans and 20 Mt of grains on dry matter basis, equivalent to 16 M ha of land used. Its adoption would require innovative policies to preserve food safety and public health. Future research may explore the feasibility and requirements to adopt swill feeding at a country level and may investigate potential impacts on other sustainability objectives.