differ to some extent between the abovementioned research, the results are highly
comparable and thus can be taken as an accurate record of the magnitude of current
wet/bulk deposition in China.
Looking beyond the results from previous studies (Lü and Tian 2014; Zhu et al.
2015; Liu et al. 2016b), the magnitude and spatial patterns of wet/bulk N deposition
varied considerably in various regions in China (Fig. 3.4). Altogether, there were
five hotspots of N deposition: north, east, southwestern and south coastal regions and
the middle Yangtze. Both NH 4
+
-N and NO 3
À -N peaked in central southern and
southeastern regions. Total wet/bulk N deposition (NH 4
+
-N plus NO 3
À
-N) displayed
a declining gradient from south to west and to north China, similar to the findings of
Xu et al. (2015) (Fig. 3.3). The fluxes were generally >35 kg N ha
1 year
À1 in
Chongqing, Hunan, Hubei and Henan, while those in other southern provinces
were 20–35 kg N ha
À1 year
À1 . Low deposition was observed in the Tibetan Plateau,
Mongolia and northwestern China.
Fig. 3.4 Spatial pattern of wet/bulk N deposition (kg N ha
À1 year
À1
) in China. (This figure was
adapted from Liu et al. 2016b under Creative Commons Attribution License)
54
X. Liu et al.