关键词: 陕北, 大气氮沉降, 湿沉降, 干沉降, AM真菌, 物种多样性, 海拔梯度, 西藏高原

Abstract: To investigate the farmland soil nitrogen input from atmospheric dry and wet deposition, a 1-year observation was conducted in the Yulin and Luochuan areas of North Shaanxi Province from June 2007 to May 2008. The total inorganic nitrogen (TIN) deposition in Yulin and Luochuan was 22.17 and 16.95 kg·hm^-2·a^-1, among which, wet deposition accounted for 95.1% and 90.4%, while dry deposition accounted for 4.9% and 9.6%, respectively, illustrating that the nitrogen deposition in both Yulin and Luochuan was mainly come from wet deposition. In the TIN deposition, the amount of nitrate in Yulin and Luochuan was 12.22 and 9.24 kg·hm^-2·a^-1, accounting for 55.1% and 54.5%, respectively. The amount of wet deposition and the percentage of nitrate in TIN deposition were higher in Yulin than in Luochuan, because of the differences in pollution level, weather condition, and underlying surface characteristics.

Key words: North Shaanxi, wet deposition, dry deposition, atmospheric nitrogen deposition, arbuscular mycorrhizal fungi, species diversity, elevational gradient, Tibetan Plateau