扎龙湿地水旱交错区土壤呼吸研究

Soil respiration in riparian zone of Zhalong wetland,northeastern China

湿地作为陆地生态系统的重要组成部分,被认为是重要的碳汇。近几十年来,湿地围垦造成土壤有机碳损失严重。全球湿地土壤的CO2温室气体排放已经相当于全球总排放的1/10。研究湿地土地利用类型的改变对土壤呼吸的影响,将有利于了解湿地碳循环,计算碳收支,制定相应对策缓解碳排放。利用LI-8100A动态密闭气室测量法,于2011年5月中旬至8月中旬,对黑龙江省扎龙湿地边缘水旱交错区自然荒地、休耕地和耕地3种土地利用类型土壤呼吸速率进行监测。结果表明,三者的平均呼吸速率分别为(4.44±1.84)μmol.m-2.s-1(自然荒地)、(5.16±3.43)μmol.m-2.s-1(休耕地)和(3.70±2.34)μmol.m-2.s-1(耕地)。土壤呼吸白天和夜晚的分配比例约为6∶4。大气温度、湿度和土壤温度是土壤呼吸的主要影响因素。气温敏感度Q10表现为自然荒地(1.86)>休耕地(1.65)>耕地(1.56)。

Wetland, as one of the most important components of terrestrial ecosystems, was recognized as the important carbon storage. In decades, the cultivation of wetland made the soil carbon storage lose seriously. CO2 emission of wetland had amounted to 1/10 of the total world emission. To study the impact of the change of land use on soil respiration will help to understand wetland carbon cycle, to calculate carbon budget, and then, to put forward the countermeasures to mitigate the carbon emission. By using LI-8100A dynamic closed chamber survey, we analyzed soil respiration of three different land uses, which are uncultivated land, fallow land and crop land, in riparian zone of Zhalong wetland during mid-May to mid-August in 2011. The results indicated that the soil respiration rate is 4.44±1.84μmol · m^-2 · s^-1 （uncultivated land）, 5.16±3.43μmol · m^- 2 . s^-1 （fallow land）, and 3. 70±2. 34 μmol · m^-2 · s^-1 （crop land）, respectively. The ratio of day time respiration to night time respiration is 6 ： 4. The main factors impacting on soil respiration are air temperature, moisture, and soil temperature. Q10, the temperature sensitivity of respiration, decreases in the order of uncultivated land （1.86）〉fallow land （1.65）〉crop land （1.56）.