Abstract
Nitrogen (N) supports food production, but its excess causes water pollution. We lack an understanding of the boundary of N for water quality while considering complex relationships between N inputs and in-stream N concentrations. Our knowledge is limited to regional reduction targets to secure food production. Here, we aim to derive a spatially explicit boundary of N inputs to rivers for surface water quality using a bottom-up approach and to explore ways to meet the derived N boundary while considering the associated impacts on both surface water quality and food production in China. We modified a multiscale nutrient modeling system simulating around 6.5 Tg of N inputs to rivers that are allowed for whole of China in 2012. Maximum allowed N inputs to rivers are higher for intensive food production regions and lower for highly urbanized regions. When fertilizer and manure use is reduced, 45–76% of the streams could meet the N water quality threshold under different scenarios. A comparison of “water quality first” and “food production first” scenarios indicates that trade-offs between water quality and food production exist in 2–8% of the streams, which may put 7–28% of crop production at stake. Our insights could support region-specific policies for improving water quality.
Original language | English |
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Pages (from-to) | 9689-9700 |
Journal | Environmental Science & Technology |
Volume | 58 |
Issue number | 22 |
DOIs | |
Publication status | Published - 4 Jun 2024 |