Reply to comments on “Imbalanced phosphorus and nitrogen deposition in China’s forests” by the Editor

Acceleration of anthropogenic emissions in China has substantially increased nitrogen (N) deposition during last three decades and may result in an imbalance of atmospheric N and phosphorus (P) inputs in terrestrial ecosystems. However, the status of P deposition in China is poorly understood. This study synthesized data on total P and total N concentrations in bulk precipitation and throughfall from published literature to assess the characteristics of P deposition, N deposition and N:P deposition ratio in China’s forests. Our results show relatively high mean rates of bulk P deposition (0.38 kg P ha -1 yr -1 ) 15 and total P deposition (0.69 kg P ha -1 yr -1 ), but they were accompanied by even much more elevated N inputs via bulk deposition (16.5 kg N ha -1 yr -1 ) and total deposition (21.6 kg N ha -1 yr -1 ), resulting in high N:P ratios in bulk deposition (44.4) and total deposition (32.8), respectively. Based on the difference between total deposition and bulk deposition, canopycaptured dry P and N deposition was estimated to be 0.31 kg P ha -1 yr -1 and 5.1 kg N ha -1 yr -1 , respectively. We found significantly higher P deposition and lower N:P ratios at sites nearby than those far from semiarid regions. The estimated 20 bulk and total deposition of P and N both showed a significant power-law increase with closer distance to the nearest large cities either in the areas nearby or far from semiarid regions. Our results suggest an anthropogenic alternation of regional P and N cycling, which might shift large areas of China’s forests towards human-induced P limitation especially in southern China.

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