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以中国亚热带木麻黄沿海防护林为研究对象,在2006年5月-2007年4月,利用LI-8100土壤呼吸自动观测系统对不同林龄(幼林、中林、成林)木麻黄人工林生态系统的土壤异养呼吸特征进行了监测。结果表明,不同林龄木麻黄林地土壤异养呼吸季节动态均呈单峰曲线,最大值出现在6～7月份,最小值则出现在12～1月份。土壤温度和水分对土壤异养呼吸的季节变化存在显著影响,并有明显的交互作用,进行单因素方差分析发现,土壤异养呼吸季节变化与5cm深的土温存在着较好的指数相关关系(p<0.05),与土壤表层含水量存在较好的线性相关关系(p<0.05)。双因素模型模拟结果显示,5cm土温和土壤表层含水量能够共同解释土壤异养呼吸变异的68.9%～91.9%(p<0.05)。不同林龄下土壤异养呼吸速率差异显著(p<0.05),其平均土壤异养呼吸速率呈现为中林>成林>幼林。随着林龄的增大,土壤异养呼吸对土壤温度的敏感性增强。土壤异养呼吸对土壤总呼吸的贡献在幼林、中林、成林中分别达到71.89%、71.02%和73.53%。幼林、中林、成林样地土壤异养呼吸CO2年释放量分别为29.072、38.964和30.530t·hm-2·a-1。
Taking the subtropical Casuarina equisetifolia protection forest in China as the research object, from May 2006 to April 2007, the LI-8100 soil respiration automatic observation system was used to study the effects of different ages (young forest, middle forest and adult forest) Soil heterotrophic respiration characteristics were monitored. The results showed that the heterotrophic respiration of Casuarina equisetifolia forest in different ages had a unimodal curve, the maximum appeared in June to July and the minimum appeared in December to January. Soil temperature and water had a significant effect on the seasonal variation of heterotrophic respiration of soil, and had obvious interaction. By one-way analysis of variance, it was found that there was a good exponential relationship between soil heterotrophic respiration and soil temperature of 5 cm depth (p <0.05), and there was a good linear relationship between soil water content and soil moisture (p <0.05). The results of two-factor model showed that soil moisture at 5cm soil depth and soil surface water content together explained 68.9% -91.9% (p <0.05) of soil heterotrophic respiration variation. The soil heterotrophic respiration rate was significantly different under different stand ages (p <0.05), and the mean soil heterotrophic respiration rate was mid-stand> stand-stand> young stand. With the increase of forest age, soil heterotrophic respiration increased the sensitivity to soil temperature. The contribution of soil heterotrophic respiration to total soil respiration was 71.89%, 71.02% and 73.53% in young forest, middle forest and mature forest respectively. The annual soil CO2 emission from heterotrophic respiration in young forest, middle forest and adult forest plots was 29.072, 38.964 and 30.530 t · hm-2 · a-1, respectively.