The present study comprehensively reports the simultaneous measurement of wet deposition of total inorganic nitrogen (TIN; which is the sum of the NH₄⁺-N and NO₃⁻-N) at three different sites in Nr emission hotspot of Indo-Gangetic plain (IGP) over a year-long temporal scale from October 2017 to September 2018. At rural Meetli (MTL) site, urban Baraut (BRT) site and industrial Loni (LNI) site, the annual wet deposition of NH₄⁺-N was estimated as 21.87, 19.48 and 7.43 kg N ha⁻¹ yr⁻¹, respectively; the annual wet deposition NO₃⁻-N was estimated as 12.96, 12.17 and 4.44 kg N ha⁻¹ yr⁻¹, respectively; and the annual wet deposition of TIN was estimated as 34.83, 31.64 and 11.87 kg N ha⁻¹ yr⁻¹, respectively. NH₄⁺-N was dominantly contributing species in annual, monsoon and non-monsoon-time wet deposition of TIN at all sites. The spatial gradient (variability) in percent contribution of NH₄⁺ to total annual volume-weighted mean (VWM) concentration of all analyte ions was observed as MTL (43.23%) > BRT (37.90%) > LNI (30%). On the other hand, the spatial gradient in percent contribution of NO₃⁻ to total annual VWM concentration of all analyte ions was observed as MTL (7.45%) > BRT (6.89%) > LNI (5.32%). The extremely narrow range of NH₄⁺-N/NO₃⁻-N ratios (ranging from 1.60 at BRT site to 1.69 at LNI site) showed the approximately equal relative abundance of oxidized and reduced nitrogen (N) deposition across all sites. Inferences from enrichment factor analysis, principal component analysis and Pearson’s correlation coefficient analysis suggested that across all sites, virtually all NH₄⁺-N and NO₃⁻-N depositions were originated anthropogenically. The annual wet deposition of TIN measured in this study showed ≥ 6865%, ≥ 6228% and ≥ 2274% increment than the natural N deposition rate at MTL, BRT and LNI site, respectively. These empirically measured annual wet depositions of TIN also emanated theoretical transgression of critical N load threshold across all sites therefore signifying probable undermining of long-term elastic stability and resilience of ecosystems against stressor in the study domain.

本研究全面报告了在印度恒河平原 Nr 排放热点的三个不同地点同时测量总无机氮 (TIN；它是 NH ₄ ⁺ -N 和 NO ₃ ^- -N 的总和) 的湿沉降 ( IGP）从 2017 年 10 月到 2018 年 9 月的一年时间尺度上。在农村 Meetli (MTL) 站点、城市 Baraut (BRT) 站点和工业 Loni (LNI) 站点，估计了 NH ₄ ⁺ -N的年湿沉降分别为 21.87、19.48 和 7.43 kg N ha ^-1  yr ^-1；年湿沉降 NO ₃ ^- -N 估计为 12.96、12.17 和 4.44 kg N ha ^-1  yr ^-1， 分别; TIN 的年湿沉降量估计分别为 34.83、31.64 和 11.87 kg N ha ^-1  yr ^-1。NH ₄ ⁺ -N是所有地点TIN年度、季风和非季风湿沉降的主要贡献物种。_{NH 4} ⁺对所有分析物离子的年总体积加权平均 (VWM) 浓度的空间梯度（变异性）观察为 MTL (43.23%) > BRT (37.90%) > LNI (30%)。另一方面，观察到 NO ₃ ^-对所有分析物离子的总年 VWM 浓度的百分比贡献的空间梯度为 MTL (7.45%) > BRT (6.89%) > LNI (5.32%)。_{NH 4}的极窄范围⁺ -N/NO ₃ ^- -N 比率（范围从 BRT 站点的 1.60 到 LNI 站点的 1.69）显示所有站点的氧化和还原氮 (N) 沉积的相对丰度大致相等。富集因子分析、主成分分析和 Pearson 相关系数分析的推论表明，在所有地点，几乎所有的 NH ₄ ⁺ -N 和 NO ₃ ^--N 沉积物是人为产生的。本研究测得的 TIN 年湿沉降量分别比 MTL、BRT 和 LNI 站点的自然 N 沉降速率增加 ≥ 6865%、≥ 6228% 和≥ 2274%。这些凭经验测量的 TIN 年度湿沉降也引发了所有地点的临界 N 负荷阈值的理论超越，因此表明可能破坏研究领域中生态系统对压力源的长期弹性稳定性和恢复力。