四种温带森林土壤氧化亚氮通量及其影响因子

以中国东北东部4种典型森林生态系统(人工红松林、落叶松林、天然次生蒙古栎林和硬阔叶林)为研究对象，采用静态暗箱-气相色谱法，比较其土壤N₂O通量的季节动态及其影响因子.结果表明：在生长季, 4种森林生态系统土壤总体上表现为大气N₂O的排放源, 其N₂O通量大小顺序为：硬阔叶林(21.0±4.9 μg·m^-2·h^-1)> 红松林(17.6±4.6 μg·m^-2·h^-1)>落叶松林(9.8±5.9 μg·m^-2·h^-1)>蒙古栎林(1.6±12.6 μg·m^-2·h^-1).各生态系统的N₂O通量没有明显的季节动态,只在夏初出现排放峰值(蒙古栎林为吸收峰).4种生态系统N₂O通量均与10 cm深土壤含水量呈极显著正相关，与NO₃^--N呈显著负相关；N₂O通量对土壤温度和NH₄⁺-N的响应出现分异：针叶林N₂O 通量与NH₄⁺-N呈显著正相关，而与5 cm深土壤温度呈不相关；阔叶林与针叶林正相反.在较为干旱的2007年，土壤水分是影响4种林型土壤N₂O通量的关键因子.植被类型与环境因子及氮素有效性对N₂O通量的相互作用将是未来研究的重点.

Soil nitrous oxide emission in four temperate forests in northeastern China.

Seasonal dynamics of N2O flux and its controlling factors for four representative temperate forests in northeastern China were examined with a static closed chamber-gas chromatograph technique. These forests were Korean pine (Pinus koraiensis) plantation, Dahurian larch (Larix gmelinii) plantation, Mongolian oak (Quercus mongolica) forest and hardwood broadleaved forest (dominated by Fraxinus mandshurica, Juglans mandshurica, and Phellodendron amurense). The results showed that all ecosystems were overall atmospheric N2O source during the growing season. The N2O flux (μg·m-2·h-1) decreased in order of the hardwood broadleaved forest (210±49)>the pine plantation (176±46)>the larch plantation (98±59)>the oak forest (16±126). Overall, there was no consistent seasonal pattern in N2O flux for the four ecosystems. The N2O flux was significantly positively correlated to soil gravimetric water content (0〖KG-*2〗-〖KG-*7〗10 cm depth) consistently for all ecosystems, but significantly negatively correlated to NO3--N content for each ecosystem. However, the responses of N2O flux to soil temperature and NH4+-N differed among the ecosystems. The N2O fluxes for the coniferous plantations were positively correlated to NH4+-N, but not correlated to the soil temperature at 5 cm depth; while those for the broadleaved forests displayed an opposite trend. The soil water content was the dominator of soil N2O emission for the forests in 2007 perhaps resulting from relative drought in the year. Interactions of vegetation type, environmental factor, and nitrogen availability to soil N2O emission should be further studied in the future.