Atmospheric nitrogen deposition in the Loess area of China

• Atmospheric deposition flux over 7 yr in Yangling of Shaanxi, China was reported.
• Atmospheric dry deposition flux estimated via a pot experiment was 23.81 N ha−1 yr−1, accounting for 45.8% the total N deposition.
• Annual N deposition uptake by plants was about 40 kg N ha−1 yr−1, accounting for 52.8% of the environmental N input.
• The N deposition rate should be controlled by using knowledge-based optimal fertilization strategies.

We present the quantification information on atmospheric nitrogen (N) deposition in the Loess area in Yangling District of Shaanxi Province, China using combined methods of a long-term field measurement (2006–2012), a potted experiment (2009–2011) and a long-term site-specific experiment (1991–2008). Our results showed that the annual deposition fluxes of dissolved inorganic N (NH4+−NNH4+−N and NO3−−NNO3−−N) via both precipitation (wet-deposition) and dustfall (dry-deposition) ranged from 12.73 to 37.87 kg N ha−1 yr−1 and averaged 21.76 kg N ha−1 yr−1, with large contributions from wet deposition. The annual mean ratios of deposition amounts of ammonium N (NH4+−NNH4+−N) to nitrate N (NO3−−NNO3−−N) were less than 1 in all the study years with an exception of the year 2007. Based on crop N uptake (approximately 52 kg N ha−1 yr−1) in the pot experiment, it was estimated that the dry N deposition fluxes (including gas and particles) was about 23.81 kg N ha−1 yr−1, accounting for 45.8% of the total N deposition. According the long-term site-specific experiment, the contribution of N input to farmland from the atmosphere was estimated to account for 52.8% of the environmental N input. Our results suggested that atmospheric N deposition was an important N input that must be taken into consideration when calculating nutrient budgets in agricultural ecosystems.