Urbanization affects water and nitrogen use in the food chain in China

ABSTRACT Urbanization and agriculture are highly coupled. However, the impacts of urbanization(e.g. transformation in urban and rural population and change in diet) on water and nitrogen (N) use remain poorly understood. The objectives of this study are to quantify water flows in the food chain of China, to analyze the complex relationship between urbanization and water and N use efficiency, and to project water and N demand in China via various scenarios, using a combination of water footprint approach and the food chain model NUFER. In 2006, China consumed in total about 857 km3 of water and 49 Tg of N, in which 132 km3 of water (15%) and 15 Tg of N (31%) were imported (as feed and food) , and 21 km3 of water (2.4%) and 5 Tg of N (10%) were exported (as feed and food). Besides that, if Chinese diet increases, especially with animal protein intake, to current European (EU-27) level, water and N use will have to increase to approximately 1600 km3 and 70 Tg, respectively. We concluded that urbanization plan in China must consider its impacts on water and N uses in the food chain, as ignoring these effects will lead to biased interpretations and unsustainable development.