Hu Zheng-hua, Li Han-mao, Yang Yan-ping, Chen Shu-tao, Li Cen-zi, Shen Shuang-he
College of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Huan Jing Ke Xue. 2010 Aug;31(8):1726-32.
To investigate the effects of elevated nitrogen deposition on forest soil respiration, a simulated nitrogen deposition field experiment was conducted in northern subtropical deciduous broad-leave forest from April 2008 to April 2009. Nitrogen treatments included the control (no N addition, CK), low-N [50 kg x (hm2 x a)(-1), T(L)], medium-N [100 kg x (hm2 x a)(-1), T(M)], and high-N [150 kg x (hm2 x a)(-1), T(H)]. The respiration rates were measured by a static chamber-gas chromatograph method. Results showed that nitrogen deposition did not change the seasonal and daily variation patterns of soil respiration. Compared to the control, T(L), T(M) and T(H) treatments reduced soil annual average respiration rates by 8.51%, 9.74% and 11.24%, respectively. Meanwhile, T(L), T(M) and T(H) treatments decreased daily average soil respiration rates by 4.42%, 11.09% and 12.17%, respectively. Significant relationship was found between soil respiration rate and soil temperature. The Q10 (temperature sensitivity coefficients) for soil respiration of CK, T(L), T(M), and T(H) treatments were 2.53, 3.22, 2.64 and 2.92, respectively. Our findings suggested that nitrogen deposition reduced soil respiration, and increased soil respiration temperature sensitivity in northern subtropical deciduous broad-leave forest.
为研究氮沉降增加对森林土壤呼吸的影响，于2008年4月至2009年4月在北亚热带落叶阔叶林开展了模拟氮沉降田间试验。氮处理包括对照（不施氮，CK）、低氮[50 kg×(hm²×a)⁻¹，T(L)]、中氮[100 kg×(hm²×a)⁻¹，T(M)]和高氮[150 kg×(hm²×a)⁻¹，T(H)]。采用静态箱-气相色谱法测定呼吸速率。结果表明，氮沉降未改变土壤呼吸的季节和日变化模式。与对照相比，T(L)、T(M)和T(H)处理分别使土壤年平均呼吸速率降低了8.51%、9.74%和11.24%。同时，T(L)、T(M)和T(H)处理分别使土壤日平均呼吸速率降低了4.42%、11.09%和12.17%。发现土壤呼吸速率与土壤温度之间存在显著关系。CK、T(L)、T(M)和T(H)处理的土壤呼吸Q10（温度敏感性系数）分别为2.53、3.22、2.64和2.92。我们的研究结果表明，氮沉降降低了北亚热带落叶阔叶林的土壤呼吸，并增加了土壤呼吸的温度敏感性。
