Abstract: To improve our understanding of the nitrogen cycle in the alpine wetlands, this study chose Zoige alpine wetland (Hongyuan  and Ruoergai counties) as study area and focused on spatial distribution of total nitrogen (TN) within soil layers (0-1.0 m), using the field investigation, laboratory analysis and GIS spatial analysis method. TN was vertically differentiated. The TN concentration and TN density decreased with increasing soil depth, being significantly higher in the topmost 0.3 m soil layer than in the 0.3-1.0 m soil layer. Horizontally, the distribution of TN was heterogeneous. The TN stock totaled 62.6 Tg in the uppermost 1.0 m soil layer of the entire study area, of which 53.4% was held in the upper most 0.3 m soil layer, with an average TN density of 3.8 kg·m^-3. The TN stock in the uppermost 1 m soil layer of permanently flooded wetland totaled 29.2 Tg, accounting for 46.7% of the TN stock in the entire study area, with an average TN density of 4.0 kg·m^-3.

Key words: soil respiration, carbon flux estimation, region division, sampling strategy.