太原市2个典型林分冬季土壤呼吸及其对温度和水分的响应

土壤呼吸随环境因素变化较大,为了探讨不同林分对土壤呼吸的影响,以典型林分国槐(Sophora japonica)林和油松(Pinus tabulaeformis)林为研究对象,于2018年11月在太原市区利用LI-8100土壤碳通量自动测量系统对2种林分土壤呼吸速率、土壤温度、土壤水分及大气温度(温度计测定)的日变化动态进行连续监测,并统计分析冬季土壤呼吸速率对温度和水分变化的响应。结果表明:(1)国槐林和油松林冬季土壤呼吸日变化明显,均呈不对称“钟形”单峰曲线。整体来看,国槐林土壤呼吸速率显著高于油松林(P<0.05)。(2)国槐林和油松林土壤呼吸速率与大气温度存在极显著的线性和指数关系,与土壤温度存在显著的线性关系。土壤温度敏感性指数Q 10值表明,油松林土壤呼吸速率对土壤温度变化更为敏感。(3)国槐林和油松林土壤呼吸速率均随土壤水分(5 cm)增加而减小,且2个林分的土壤呼吸速率与土壤水分(5 cm)之间均呈极显著的线性负相关关系。

Soil Respiration and Its Response to Temperature and Moisture in Two Typical Stands of Taiyuan City in Winter

In order to investigate the effects of different stands on soil respiration and analyze the response of soil respiration rate to temperature and moisture change in winter,Sophora japonica Forest and Pinus tabulaeformis Forest with typical stands were studied,by using the LI-8100 soil carbon automatic measurement system to continuously monitor the diurnal changes of soil respiration rate,soil temperature,soil moisture and atmospheric temperature(thermometric measurement)of two stands in Taiyuan in November 2018.The diurnal changes of soil respiration in S.japonica forest and P.tabulaeformis forest were obvious in winter,showing an asymmetric“bell shaped”single-peak curve.Overall,the soil respiration rate of S.japonica forest was significantly higher than that of P.tabulaeformis forest(P<0.05).There was a highly significant linear and exponential relationship between soil respiration rate and air temperature,and there was a significant linear between soil respiration rate and soil temperature in S.japonica forest and P.tabulaeformis forest.The analysis of soil temperature sensitivity index Q 10 shows that the soil respiration rate of P.tabulaeformis forest was more sensitive to the change of soil temperature.Soil respiration rate of S.japonica forest and P.tabulaeformis forest decreased with the increase of soil moisture(5 cm),and there was a significant negative linear correlation between soil respiration rate of two stands and soil moisture(5 cm).