Water resources conservation and nitrogen pollution reduction under global food trade and agricultural intensification

Wenfeng Liu (Corresponding Author), Hong Yang, Yu Liu, Matti Kummu, Arjen Y. Hoekstra, Junguo Liu, Rainer Schulin

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)
147 Downloads (Pure)

Abstract

Global food trade entails virtual flows of agricultural resources and pollution across countries. Here we performed a global-scale assessment of impacts of international food trade on blue water use, total water use, and nitrogen (N) inputs and on N losses in maize, rice, and wheat production. We simulated baseline conditions for the year 2000 and explored the impacts of an agricultural intensification scenario, in which low-input countries increase N and irrigation inputs to a greater extent than high-input countries. We combined a crop model with the Global Trade Analysis Project model. Results show that food exports generally occurred from regions with lower water and N use intensities, defined here as water and N uses in relation to crop yields, to regions with higher resources use intensities. Globally, food trade thus conserved a large amount of water resources and N applications, and also substantially reduced N losses. The trade-related conservation in blue water use reached 85 km3 y−1, accounting for more than half of total blue water use for producing the three crops. Food exported from the USA contributed the largest proportion of global water and N conservation as well as N loss reduction, but also led to substantial export-associated N losses in the country itself. Under the intensification scenario, the converging water and N use intensities across countries result in a more balanced world; crop trade will generally decrease, and global water resources conservation and N pollution reduction associated with the trade will reduce accordingly. The study provides useful information to understand the implications of agricultural intensification for international crop trade, crop water use and N pollution patterns in the world.
Original languageEnglish
Pages (from-to)1591-1601
Number of pages11
JournalScience of the total environment
Volume633
Early online date4 Apr 2018
DOIs
Publication statusPublished - 15 Aug 2018

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