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在中高纬度和高海拔地区,冻融作用影响土壤的理化性质和微生物性状,进而影响土壤呼吸过程。研究冻融作用下土壤呼吸的变化,对准确估算全球碳循环具有重要意义。以科尔沁沙地沙质草地、樟子松疏林草地和农田为研究对象,通过冻融实验比较不同土地利用方式和冻融循环对土壤呼吸的影响。结果表明:土地利用方式对土壤呼吸有显著影响,在未发生冻融作用时沙质草地土壤呼吸速率显著大于樟子松疏林草地和农田(P<0.05),3种土地利用方式的土壤呼吸平均速率分别为0.339、0.258和0.234μmolCO2.m-2.s-1;不同冻融循环对沙质草地和樟子松疏林草地土壤呼吸影响显著(P<0.05)。其中,一次冻融循环条件下沙质草地、樟子松疏林草地和农田土壤呼吸平均速率分别为0.276、0.243和0.233μmolCO2.m-2.s-1,多次冻融循环条件下分别为0.314、0.274和0.259μmolCO2.m-2.s-1;沙质草地、樟子松疏林草地和农田的Q10值分别为116.0、26.2和16.4,表明冬季低温条件下土地利用方式强烈影响土壤呼吸对温度的敏感性。
In the middle and high latitudes and at high altitudes, the freeze-thaw effect affects soil physicochemical properties and microbial characteristics, which in turn affects the soil respiration process. Studying the change of soil respiration under the effect of freezing and thawing is of great significance for accurately estimating the global carbon cycle. The sandy grassland in the Horqin sandy land and the sparse-grass grassland and farmland of Pinus sylvestris var. Mongolica were selected as the research objects. The effects of different land use patterns and freeze-thaw cycles on soil respiration were compared by means of freeze-thaw experiments. The results showed that: the land use pattern had a significant effect on soil respiration, soil respiration rate in sandy grassland was significantly greater than that in Pinus sylvestris var.mongolica forest and farmland (P <0.05), and the soil respiration of three land use patterns The average rates were 0.339,0.258 and 0.234μmolCO2.m-2.s-1, respectively. The effects of different freeze-thaw cycles on soil respiration of sandy grassland and Pinus sylvestris var.mongolica forest were significant (P <0.05). Among them, the average soil respiration rates of sandy grassland, Scotch Pine forest soil and farmland were 0.276,0.243 and 0.233μmolCO2.m-2.s-1 respectively in a freeze-thaw cycle, and were 0.314 , 0.274 and 0.259μmolCO2.m-2.s-1, respectively. The Q10 values of sandy grassland, Pinus sylvestris var.mongolica forest and farmland were 116.0, 26.2 and 16.4, respectively, indicating that the land use pattern strongly influenced soil respiration Temperature sensitivity.