大气氮沉降对三峡库区消落带土壤呼吸的影响

Effects of atmospheric nitrogen deposition on soil respiration in the water level fluctuating zone of the Three Gorges Reservoir area

以三峡库区消落带落干期土壤为研究对象,采用室内模拟培养的方法,探讨了大气氮沉降通量及其组成对土壤呼吸的影响.结果表明,土壤呼吸速率对氮添加的响应为短期效应.1倍当前大气氮沉降添加下,无机氮和有机氮对土壤累积CO_2释放分别表现为无影响和抑制作用.除NH_4^+-N在2倍氮沉降添加下表现为抑制作用外, 2、3倍氮沉降添加均促进了土壤累积CO_2释放.与硝态氮相比, 2、3倍氮沉降添加的铵态氮对土壤累积CO_2释放具有抑制作用.

An indoor incubation experiment was conducted to reveal the effect of atmospheric nitrogen deposition on soil respiration of water level fluctuating zone in the Three Gorges Reservoir area. The results showed that the response of soil respiration rate to nitrogen addition was a short term effect. Under the present atmospheric nitrogen deposition flux, soil cumulative CO2 release was not changed by inorganic nitrogen addition, while, it was inhibited by organic nitrogen addition. Except soil cumulative CO2 release was depressed by ammonium addition of double present atmospheric nitrogen deposition flux, it was promoted by all the simulated atmospheric nitrogen deposition composition under both double and triple present atmospheric nitrogen deposition flux. Compared with ammonium, nitrate was more conducive for promoting cumulative CO2 release under double and triple present atmospheric nitrogen deposition flux.