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    采伐对蛟河阔叶红松混交林土壤呼吸的影响

    Effects of cutting on soil respiration in a mixed broadleaf-Korean pine forest in western foothill of Changbai Mountain, northeast China

    • 摘要: 为分析不同采伐强度下土壤呼吸速率的差异及土壤温湿度对土壤呼吸速率的影响,于2013—2015年5—10月,在吉林省蛟河红松阔叶混交林地表无雪期间,使用LI-8100土壤CO2全自动通量测量仪器测量定不同采伐强度土壤呼吸速率及土深5 cm处温、湿度,采伐强度分别为:对照0%、轻度采伐15%、中度采伐25%、重度采伐50%。结果表明:采伐使土壤温度增加、土壤湿度降低。不同采伐强度处理样地的土壤呼吸速率值均显著大于对照样地,在研究的第1年与第2年,轻度采伐与重度采伐样地的土壤呼吸速率之间无显著差异(P>, 0.05),而中度采伐样地的土壤呼吸速率要显著高于轻度采伐处理和重度采伐处理的土壤呼吸速率(P<, 0.05)。在研究的第3年各采伐强度处理的土壤呼吸速率之间差异均不显著(P>, 0.05)。不同采伐强度样地的土壤呼吸与土壤温度之间均呈显著指数相关(P<, 0.001),但与土壤湿度之间相关关系不显著(P>, 0.05)。土壤温度和土壤湿度的双变量复合模型能够更好地解释土壤呼吸速率变化,决定系数R值为45%~74%。各采伐强度处理的土壤呼吸的温度敏感系数Q10值表现为中度采伐>, 重度采伐>, 轻度采伐=对照。在实践生产中,为减小采伐后林地土壤CO2的呼吸量,应采用低强度的采伐作业。

       

      Abstract: The objective of this study was to explore the difference in soil respiration rate under different intensities of cutting as well as the effects of soil temperature and moisture content on soil respiration rate. We measured soil respiration using infrared gas exchange analyzer of Li-Cor 8100 in the daytime during the growing seasons (May-October) of 2013-2015 in a mixed broadleaf-Korean pine (Pinus koraiensis) forest with heavy (50%), medium (25%) and light (15%) intensity cutting and uncut control (0%) plots in Jiaohe, Jilin Province in northeast China. We found that with cutting intensity increasing, soil temperature increased, and soil moisture reduced. Cutting significantly affected soil respiration and soil temperature, while there were no significant differences in soil moisture under different cutting intensities. During the growing seasons, a positive correlation was found between soil respiration and soil temperature at all sites. The best fitting model with temperature explained 73% of the variation in soil respiration in the heavy cutting treatment, 65% in the light cutting treatment,58% in the control sites, and 43% in medium cutting treatment during the measuring periods.In order to predict both soil moisture and soil temperature dependency, four two-variable linear/non-linear models were developed and evaluated.By use of those models it is possible to predict the soil respiration as a function of both temperature and moisture, with R values ranging from 45%-74%. The Q10 values were increased in the treatments of medium (2.46), heavy (2.44) and light (2.39) intensity cutting relative to the control (2.39). Our findings suggest that in order to reduce the forest soil surface CO2 emission after cutting, a reasonable cutting intensity about 15% should be adopted.

       

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