秦岭火地塘林区油松生长季土壤呼吸研究

Soil respiration of Pinus tabulaeformis forest during the growing season at Huoditang Forest Region in the Qinling Mountains

【目的】阐明秦岭火地塘林区油松林生态系统土壤呼吸对其影响因子变化的响应机制。【方法】2010年6-11月,利用LI-6400便携式光合作用测量系统,测定秦岭火地塘油松林在生长季的土壤呼吸速率,并利用LAI-2000植物冠层分析仪测定油松林的叶面积指数,同时还测定了5cm深处的土壤温度以及土壤含水量。【结果】油松林土壤呼吸速率存在明显的季节变化,土壤呼吸动态呈单峰型变化:8月下旬达到最大值3.69μmol/(m2.s),最小值出现在11月下旬,为0.52μmol/(m2.s),整个生长季的平均值为1.82μmol/(m2.s)。土壤呼吸速率与5cm深处的土壤温度变化基本保持一致,二者呈三次函数关系,相关性极显著;土壤呼吸速率与油松叶面积指数呈S型函数关系,相关性显著;土壤呼吸速率与土壤含水量呈S型函数关系,二者相关性不显著。油松林生长季土壤呼吸的温度敏感性指数Q10值为3.63。【结论】影响秦岭火地塘林区油松林土壤呼吸速率的最主要因子是5cm深处的土壤温度,其次是叶面积指数,土壤含水量对土壤呼吸速率的影响不显著。

【Objective】 The study was to clarify the mechanism of soil respiration responding to changing of influence factors in forest ecosystem of Qinling Mountains.【Method】 Soil respiration rate was measured by LI-6400 portable photosynthesis measuring system during the growing season at Huoditang forest region in the Qinling Mountains.Leaf area index was measured by LAI-2000 plant canopy analyzer from June 2010 to November 2010.At the same time,the soil temperature and soil moisture content at 5 cm depth were measured.【Result】 Pinus tabulaeformis forest had significantly different patterns in seasonal soil respiration processes,the tendencies of soil respiration appeared single peak variation.The maximum rate of soil respiration was 3.69 μmol/（m2·s）,appearing in the last ten days of August,the minimum rate of soil respiration was 0.52 μmol/（m2·s） in the last ten days of November,and the average value of soil respiration rate during the growing season was 1.82 μmol/（m2·s）.Soil respiration varied similar to soil temperature at 5 cm depth.Soil respiration showed a cubic functional relationship with soil temperature at 5 cm depth,the relevance between them was extremely notable;soil respiration had a S type functional relationship with leaf area index,the relevance between them was notable;soil respiration had a S type functional relationship with soil moisture content,the relevance between them was not notable.The index of temperature sensibility Q10 values was 3.63 in the growing seasons.【Conclusion】 Main factor affecting the soil respiration was soil temperature at 5 cm depth,secondly was leaf area index.The relevance between soil respiration and soil moisture content was not notable.