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根据远红外气体分析原理,采用Li-6400-09土壤呼吸室和Li-6400光合速率测定仪对川西北高寒草甸土壤呼吸速率日变化进行测定,并同步记录大气温度、0、5、10、15和20 cm地温,探讨温度对土壤呼吸速率的影响.结果表明,在选取的浅丘山地灌丛(US)、浅丘山地草甸(UM)、丘前阶地草甸(TM)3块样地中,土壤呼吸速率日变化均呈单峰型,日均呼吸速率是UM((5.34±0.339)μmol.m-2.s-1)>US((5.14±0.225)μmol.m-2.s-1)>TM((4.49±0.282)μmol.m-2.s-1),差异极显著(P<0.01).大气温度、0和5 cm地温与3块样地土壤呼吸速率相关性最强,以5 cm地温最突出;10 cm地温与呼吸速率相关性较好;15和20 cm地温与呼吸速率相关性很小.基于Q10值,土壤呼吸速率对5 cm地温的变化最敏感,各样地对温度的响应是UM>US>TM.
According to the principle of far-infrared gas analysis, the diurnal variation of soil respiration rate in the alpine meadow in northwestern Sichuan was measured by using Li-6400-09 soil respiration chamber and Li-6400 photosynthesis rate measuring instrument. The atmospheric temperature, 0, 5, 10, 15 and 20 cm ground temperature, the effects of temperature on soil respiration rate were studied.The results showed that in the three sample plots of the shallow hillside shrub (US), the hillock meadows (UM) and the hilltop meadow , Diurnal variation of soil respiration rate showed a single peak, and the average daily respiration rate was UM (5.34 ± 0.339 μmol.m-2.s-1)> US (5.14 ± 0.225) μmol.m-2.s- 1)> TM (4.49 ± 0.282) μmol.m-2.s-1), and the difference was significant (P <0.01) .The correlation between the air temperature, 0 and 5 cm soil temperature and the soil respiration rate in the three plots was the strongest , With 5 cm ground temperature the most prominent; 10 cm ground temperature and respiratory rate correlation is good; 15 and 20 cm ground temperature and respiratory rate is very small. Based on the Q10 value, soil respiration rate of 5 cm of ground temperature changes the most sensitive, The response to temperature is UM> US> TM.