全球变化知识资源中心

Increasing atmospheric nitrogen deposition can influence food production, environmental quality and climate change from the regional to global scales. As the largest developing country, China is expected to experience a rapid increase in N deposition. However, the lack of information on dry N deposition limits our understanding of the historical trend of the total N deposition, as well as the main drivers of this trend. Here, we use extensive datasets that include both wet and dry N deposition to evaluate the spatiotemporal variation of N deposition and the changes of its components in China during 1980-2015. Three significant transitions in N deposition in China were observed. First, the total N deposition began to stabilize in 2001-2005, mostly due to a decline in wet NH4+ deposition. Subsequently, a shift to approximately equal wet and dry N deposition occurred in 2011-2015, accompanied by increasing dry deposition. Finally, the contribution of reduced N components in the deposition decreased due to increasing NO3- deposition. These transitions were jointly driven by changes in the socioeconomic structure in China and vigorous controls in N pollution. The three observed important transitions challenge the traditional views about the continuous increase in N deposition in China.