Quantification of nitrogen dry and wet deposition in Fujian tobacco planting area

The annual mean total dry deposition was estimated to be 9.6 kg N ha−1 a−1, and those of the individual species, gNH3, gNO2, gHNO3, pNH4+, and pNO3− were estimated to be 4.1, 2.2, 2.0, 0.8, and 0.4 kg N ha−1 a−1, respectively. Based on the similarities in wet deposition, if we assume a similar level of dry deposition at all the sites, the total (dry and wet) N deposition was 27.2 kg N ha−1 a−1 on average, which twice the critical load (10-15 kg N ha−1 a−1) for forest ecosystems, suggesting a risk of “N saturation” in the local natural environment.