科尔沁沙地夏秋(6—9月)季不同类型沙丘土壤呼吸对气温变化的响应

Responses of Soil Respiration to Air Temperature from June to September in Different Sand Dunes,Horqin Sandy Land

通过测定分析了科尔沁沙地6—9月不同生境(固定、半固定和流动沙丘)土壤呼吸速率的日动态、月际动态及其对气温变化的响应。结果表明:测定期平均土壤呼吸速率在各生境间存在显著差异,其大小为固定沙丘(2.35μmolCO2.m-2.s-1)>半固定沙丘(1.67μmolCO2.m-2.s-1)>流动沙丘(1.06μmolCO2.m-2.s-1);指数模型能够较好地揭示不同生境土壤呼吸对气温变化的响应,但土壤呼吸的月际动态与气温变化不完全同步;各生境土壤在高温环境下的Q10值(土壤呼吸对温度敏感程度)普遍低于低温环境下的Q10值;固定、半固定和流动沙丘基于气温月际变化的Q10值分别为2.34、1.99和1.31,表明不同的植被状况和土壤性质会影响到土壤呼吸对温度变化的敏感程度。

The daily and monthly variations of soil respiration and its responses to air temperature were determined in different habitats（fixed,semi-fixed and moving sand dune） in Horqin sandy land,from June to September of 2005.The mean soil respiration rates were in the following order： fixed sand dune（2.35 μmolCO2 μm-2／5s-1）〉semi-fixed sand dune（1.67 μmolCO2／5m-2／5s-1）〉moving sand dune（1.06molCO2 μm-2／5s-1）,which had significant difference among the three habitats during study period.The relationships between soil respiration rate and temperature in three habitats could be best described by exponential equations.The monthly variations of soil respiration were similar to those of temperature,but were not completely consistent with each other.The Q10 value（sensitivity of soil respiration to temperature） at higher temperature was lower than that at low temperature.Corresponding to monthly temperature regime,the Q10 values of fixed,semi-fixed and moving sand dune were 2.34,1.99,and 1.31,respectively,which implied that different vegetation condition and soil character could affect the sensitivity of soil respiration to temperature.