how they influence NUE and subsequent N losses to the environment is therefore
essential. The spatial variation of the total anthropogenic N released to the environment following the N footprint [5] is shown in Fig. 2.
Fig. 1 Virtual nitrogen factor for maize crop in the United States (Leach et al. [3]; www.n-print.
org)
Fig. 2 Spatial variation of the anthropogenic N losses in different countries [5]
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essential. The spatial variation of the total anthropogenic N released to the environment following the N footprint [5] is shown in Fig. 2.
Fig. 1 Virtual nitrogen factor for maize crop in the United States (Leach et al. [3]; www.n-print.
org)
Fig. 2 Spatial variation of the anthropogenic N losses in different countries [5]
Nitrogen Footprints and the Role …
135