Fig. 3: Nitrogen budgets within key subsystems and their contribution to N losses reduction with urbanization.
From: Managing urban development could halve nitrogen pollution in China
Total N budgets for four subsystems and the environment in 2017 (a) and 2050 (b). These four subsystems, i.e. cropland, livestock, human and nature, are defined by the CHANS model. Human subsystem set includes urban human, rural human, wastewater treatment, garbage treatment and industry subsystems. Nature subsystem set includes grassland and forest subsystem. The colored arrows represent N flows to varying subsystems as follows: yellow, cropland subsystem; green, livestock subsystem; blue, human subsystem; brown, nature subsystem. The black arrows indicate the N flows that eventually enter the atmosphere and water bodies through gaseous emissions and runoff losses. c–f National nitrogen losses in 2017 and 2050, and the sources of the difference. The icons used in (a) and (b) are from https://uxwing.com/.
