山区不同海拔植烟土壤温室气体排放特征及其温湿度敏感性

徐祥玉; 张敏敏; 周剑雄; 夏鹏亮; 任晓红

doi:10.12357/cjea.20250091

摘要: 温室气体（GHG）排放是全球气候变化的重要驱动因素，而土壤碳氮循环在农业生态系统中发挥着关键作用。尽管已有大量研究，但不同海拔梯度下烟田土壤中 CO₂、CH₄和 N₂O排放特征及其对土壤温度和湿度响应的机制仍不明确。本研究选取湖北恩施地区海拔 800–1200 m 范围内10个烟田采样点，采用静态箱–气相色谱法现场监测温室气体通量，并通过插值法计算累积排放量。结果表明：① CO₂通量随海拔升高显著下降，且CO₂累积排放量与海拔呈显著负相关（R² = 0.47, p < 0.05）；② CH₄作为汇，其通量呈非线性（二次）变化，且累积 CH₄排放量与海拔显著相关（R² = 0.45, p < 0.05）；③ 尽管N₂O瞬时通量在各海拔间无显著差异，但其累积排放量随海拔显著降低（R² = 0.65, p < 0.01）；④ CO₂的温度敏感性（Q₁₀）在中海拔区域最低，而其湿度敏感性与海拔呈显著负相关；相反，CH₄ 的温度敏感性在中海拔区域达到峰值，其湿度敏感性与海拔呈显著正相关；N₂O的温度敏感性与海拔显著负相关，而湿度敏感性则显著正相关。总体来看，海拔通过调控土壤温度和湿度间接影响温室气体排放，对区域碳循环具有重要调控作用。本研究为山区烟田温室气体排放的精细估算和减排管理提供了坚实的科学依据。

Abstract: 165102057400 >Abstract: Greenhouse gas (GHG) emissions are a significant driver of global climate change, and the soil carbon and nitrogen cycles play a key role in agricultural ecosystems. Despite numerous studies, the emission characteristics of CO₂, CH₄, and N₂O in tobacco field soils across different elevation gradients, as well as their responses to soil temperature and moisture, remain unclear. This study selected 10 tobacco field sampling points within an elevation range of 800–1200 m in Enshi, Hubei Province, and used static chamber-gas chromatography for on-site monitoring of GHG fluxes. Cumulative emissions were calculated using interpolation methods. The results showed that: (1) CO₂ flux significantly decreased with increasing elevation, and the cumulative CO₂ emissions were negatively correlated with elevation (R² = 0.47, p < 0.05); (2) CH₄, as a sink, exhibited a nonlinear (quadratic) flux pattern, and cumulative CH₄ emissions were significantly correlated with elevation (R² = 0.45, p < 0.05); (3) Although there was no significant difference in the instantaneous N₂O fluxes across elevations, its