摘要
对三江平原小叶章（Calamagrostis angustifo施）沼泽化草甸进行为期2a的模拟氮沉降实验，氮沉降水平分别为对照loeC（m2·a）氮]、低氮[4g／（m^2·a）氮]和高氮F8g／（m^2·a）氮]。采用动态气室法（LI．6400—09叶室连接到LI．6400便携式CO2／H2O分析系统）测定土壤呼吸速率。结果表明，小叶章沼泽化草甸土壤呼吸速率季节动态曲线呈抛物线模式，在7月达到最高值；土壤呼吸速率和土壤温度之间呈显著的指数相关关系（R^2为0．47-0．69）；仅高氮处理土壤呼吸速率与土壤含水量表现出负指数相关关系60〈0．05，R^2=0．27）；氮沉降对土壤呼吸的影响依据氮沉降水平而异，低氮处理下，土壤呼吸速率为（5．57±0．91）um01／（m^2·s），比对照处理土壤呼吸速率（5．18±0．86）μmol／（m^2·s）高8％60〈0．05），高氮处理的土壤呼吸速率（4．93±0．53）pmol／（m^2·s）则比对照处理稍低。不同氮沉降处理下，土壤呼吸温度系数Q10值分别为2．93、2．43和2．03，Q10值随着氮沉降水平呈现逐渐降低的趋势。氮沉降可能抑制了土壤呼吸的温度敏感性。
To study the effects of simulated nitrogen deposition on soil respiration in a Calamagrostis angustifo- lia marshy meadow of Sanjiang Plain, beginning in 2009, an experiment in situ was conducted. The level of ni- trogen deposition were control[0 g/（m2. a） nitrogen], low nitrogen[-4 g/（m2 · a） nitrogen] and high nitrogen[8 g/（m2 ·a） nitrogen]. The soil respiration was measured by infrared gas analyzer （LI-6400, Li-Cor, USA） over the growing seasons in 2010. The results indicated that soil respiration followed parabolic-like pattern with higher values in July. Moreover, soil respiration rate had significant positive exponential relationships with soil temperature at 5 cm depth （P〈0.001, R2 were 0.47-0.69）, and significant negative exponential relation- ships with soil water content only in HN treatment （R2 = 0.27）. The mean rate of soil respiration under LN treatment was （5.57 ± 0.91） μmol/（m2. s） and significantly increased 8% comparing with control level （5.18 ± 0.86） μmol/（m2 ·s）. The mean rate of soil respiration under HN treatment was （4.93 ±0.53） μmol/（m2·s） and slightly decreased comparing with control level. The temperature coefficient of soil respiration（Q10） values at three different nitrogen treatment levels were 2.93, 2.43 and 2.03, respectively. Compared with control level, nitrogen deposition decreased the Q10 values. The results indicated that LN treatment enhanced soil respiration rate and HN treatment inhibited soil respiration rate. Furthermore, nitrogen deposition may reduce tempera- ture sensitivity of soil respiration.
出处
《湿地科学》
CSCD
北大核心
2014年第1期66-72,共7页
Wetland Science
基金
国家自然科学基金项目(30970452)
黑龙江省省财政基本科研业务费项目(2012EFA-02)资助
关键词
氮沉降
小叶章沼泽化草甸
土壤呼吸
土壤温度
nitrogen deposition
Calamagrostis angustifolia marshy meadow
soil respiration
soil temperature
