How China's nitrogen footprint of food has changed from 1961 to 2010

Mengchu Guo, Xiaohui Chen, Zhaohai Bai, Rongfeng Jiang*, James N. Galloway, Allison M. Leach, Lia R. Cattaneo, Oene Oenema, Lin Ma, Fusuo Zhang

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

20 Citations (Scopus)

Abstract

People have increased the amount of reactive nitrogen (Nr) in the environment as a result of food production methods and consumption choices. However, the connection between dietary choices and environmental impacts over time has not yet been studied in China. Here we combine a nitrogen footprint tool, the N-Calculator, with a food chain model, NUFER (NUtrient flows in Food chains, Environment and Resources use), to analyze the N footprint of food in China. We use the NUFER model to provide a detailed estimation of the amounts and forms of Nr released to the environment during food production, which is then used to calculate virtual nitrogen factors (VNFs, unit: kg N released/kg N in product) of major food items. The food N footprint consists of the food consumption N footprint and food production N footprint. The average per capita food N footprint increased from 4.7 kg N capita-1 yr-1 in the 1960s to 21 kg N capita-1 yr-1 in the 2000s, and the national food N footprint in China increased from 3.4 metric tons (MT) N yr-1 in the 1960s to 28 MT N yr-1 in the 2000s. The proportion of the food N footprint that is animal-derived increased from 37% to 54% during this period. The food production N footprint accounted for 84% of the national food N footprint in the 2000s, compared to 62% in the 1960s. More Nr has been added to the food production systems to produce enough food for a growing population that is increasing its per-capita food consumption. The increasing VNFs in China indicate that an increasing amount of Nr is being lost per unit of N embedded in food products consumed by humans in the past five decades. National N losses from food production increased from 6 MT N yr-1 in the 1960s to 23 MT N yr-1 in the 2000s. N was lost to the environment in four ways: ammonia (NH3) emissions and dinitrogen (N2) emissions through denitrification (each account for nearly 40%), N losses to water systems (20%), and nitrous oxide (N2O) emissions (1%). The average per capita food N footprint in China is relatively high compared with those of developed countries in the 2000s. To reduce the food N footprint in China, it is important to both reduce the Nr losses during food production and encourage diets associated with a lower N footprint, such as shifting towards a more plant-based diet.
Original languageEnglish
Article number104006
JournalEnvironmental Research Letters
Volume12
Issue number10
DOIs
Publication statusPublished - 4 Oct 2017

Keywords

  • China
  • Nitrogen footprint
  • nitrogen losses
  • virtual nitrogen factor

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